From: Peter Johnson Date: Sun, 7 Apr 2002 19:13:03 +0000 (-0000) Subject: Initial revision X-Git-Tag: v0.2.0~273 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d93c3d4735833d8ba26a0401d1efd28956ef2ffc;p=yasm Initial revision svn path=/trunk/yasm/; revision=552 --- diff --git a/tools/lemon/README b/tools/lemon/README new file mode 100644 index 00000000..64959028 --- /dev/null +++ b/tools/lemon/README @@ -0,0 +1,15 @@ +$Id: README,v 1.1 2002/04/07 19:13:05 peter Exp $ + +The Lemon Parser Generator's home page is: + +http://www.hwaci.com/sw/lemon/index.html + +The file in this directory, lemon.html, was obtained from: + +http://www.hwaci.com/sw/lemon/lemon.html + +lemon.c has been modified to include the t= and d= command-line +arguments. The changes were submitted to the Lemon maintainer, +but have not appeared in the official Lemon distribution. + + diff --git a/tools/lemon/lemon.c b/tools/lemon/lemon.c new file mode 100644 index 00000000..e4310c7a --- /dev/null +++ b/tools/lemon/lemon.c @@ -0,0 +1,4116 @@ +/* +** Copyright (c) 1991, 1994, 1997, 1998 D. Richard Hipp +** +** This file contains all sources (including headers) to the LEMON +** LALR(1) parser generator. The sources have been combined into a +** single file to make it easy to include LEMON as part of another +** program. +** +** This program is free software; you can redistribute it and/or +** modify it under the terms of the GNU General Public +** License as published by the Free Software Foundation; either +** version 2 of the License, or (at your option) any later version. +** +** This program is distributed in the hope that it will be useful, +** but WITHOUT ANY WARRANTY; without even the implied warranty of +** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +** General Public License for more details. +** +** You should have received a copy of the GNU General Public +** License along with this library; if not, write to the +** Free Software Foundation, Inc., 59 Temple Place - Suite 330, +** Boston, MA 02111-1307, USA. +** +** Author contact information: +** drh@acm.org +** http://www.hwaci.com/drh/ +** +** $Id: lemon.c,v 1.1 2002/04/07 19:13:04 peter Exp $ +*/ +#include +#include +#include +#include + +extern void qsort(); +extern double strtod(); +extern long strtol(); +extern void free(); +extern int access(); +extern int atoi(); + +#ifndef __WIN32__ +# if defined(_WIN32) || defined(WIN32) +# define __WIN32__ +# endif +#endif + +/* #define PRIVATE static */ +#define PRIVATE + +#ifdef TEST +#define MAXRHS 5 /* Set low to exercise exception code */ +#else +#define MAXRHS 1000 +#endif + +char *msort(); +extern void *malloc(); + +/******** From the file "action.h" *************************************/ +struct action *Action_new(); +struct action *Action_sort(); +void Action_add(); + +/********* From the file "assert.h" ************************************/ +void myassert(); +#ifndef NDEBUG +# define assert(X) if(!(X))myassert(__FILE__,__LINE__) +#else +# define assert(X) +#endif + +/********** From the file "build.h" ************************************/ +void FindRulePrecedences(); +void FindFirstSets(); +void FindStates(); +void FindLinks(); +void FindFollowSets(); +void FindActions(); + +/********* From the file "configlist.h" *********************************/ +void Configlist_init(/* void */); +struct config *Configlist_add(/* struct rule *, int */); +struct config *Configlist_addbasis(/* struct rule *, int */); +void Configlist_closure(/* void */); +void Configlist_sort(/* void */); +void Configlist_sortbasis(/* void */); +struct config *Configlist_return(/* void */); +struct config *Configlist_basis(/* void */); +void Configlist_eat(/* struct config * */); +void Configlist_reset(/* void */); + +/********* From the file "error.h" ***************************************/ +void ErrorMsg( /* char *, int, char *, ... */ ); + +/****** From the file "option.h" ******************************************/ +struct s_options { + enum { OPT_FLAG=1, OPT_INT, OPT_DBL, OPT_STR, + OPT_FFLAG, OPT_FINT, OPT_FDBL, OPT_FSTR} type; + char *label; + char *arg; + char *message; +}; +int optinit(/* char**,struct s_options*,FILE* */); +int optnargs(/* void */); +char *optarg(/* int */); +void opterr(/* int */); +void optprint(/* void */); + +/******** From the file "parse.h" *****************************************/ +void Parse(/* struct lemon *lemp */); + +/********* From the file "plink.h" ***************************************/ +struct plink *Plink_new(/* void */); +void Plink_add(/* struct plink **, struct config * */); +void Plink_copy(/* struct plink **, struct plink * */); +void Plink_delete(/* struct plink * */); + +/********** From the file "report.h" *************************************/ +void Reprint(/* struct lemon * */); +void ReportOutput(/* struct lemon * */); +void ReportTable(/* struct lemon * */); +void ReportHeader(/* struct lemon * */); +void CompressTables(/* struct lemon * */); + +/********** From the file "set.h" ****************************************/ +void SetSize(/* int N */); /* All sets will be of size N */ +char *SetNew(/* void */); /* A new set for element 0..N */ +void SetFree(/* char* */); /* Deallocate a set */ + +int SetAdd(/* char*,int */); /* Add element to a set */ +int SetUnion(/* char *A,char *B */); /* A <- A U B, thru element N */ + +#define SetFind(X,Y) (X[Y]) /* True if Y is in set X */ + +/********** From the file "struct.h" *************************************/ +/* +** Principal data structures for the LEMON parser generator. +*/ + +typedef enum {FALSE=0, TRUE} Boolean; + +/* Symbols (terminals and nonterminals) of the grammar are stored +** in the following: */ +struct symbol { + char *name; /* Name of the symbol */ + int index; /* Index number for this symbol */ + enum { + TERMINAL, + NONTERMINAL + } type; /* Symbols are all either TERMINALS or NTs */ + struct rule *rule; /* Linked list of rules of this (if an NT) */ + int prec; /* Precedence if defined (-1 otherwise) */ + enum e_assoc { + LEFT, + RIGHT, + NONE, + UNK + } assoc; /* Associativity if predecence is defined */ + char *firstset; /* First-set for all rules of this symbol */ + Boolean lambda; /* True if NT and can generate an empty string */ + char *destructor; /* Code which executes whenever this symbol is + ** popped from the stack during error processing */ + int destructorln; /* Line number of destructor code */ + char *datatype; /* The data type of information held by this + ** object. Only used if type==NONTERMINAL */ + int dtnum; /* The data type number. In the parser, the value + ** stack is a union. The .yy%d element of this + ** union is the correct data type for this object */ +}; + +/* Each production rule in the grammar is stored in the following +** structure. */ +struct rule { + struct symbol *lhs; /* Left-hand side of the rule */ + char *lhsalias; /* Alias for the LHS (NULL if none) */ + int ruleline; /* Line number for the rule */ + int nrhs; /* Number of RHS symbols */ + struct symbol **rhs; /* The RHS symbols */ + char **rhsalias; /* An alias for each RHS symbol (NULL if none) */ + int line; /* Line number at which code begins */ + char *code; /* The code executed when this rule is reduced */ + struct symbol *precsym; /* Precedence symbol for this rule */ + int index; /* An index number for this rule */ + Boolean canReduce; /* True if this rule is ever reduced */ + struct rule *nextlhs; /* Next rule with the same LHS */ + struct rule *next; /* Next rule in the global list */ +}; + +/* A configuration is a production rule of the grammar together with +** a mark (dot) showing how much of that rule has been processed so far. +** Configurations also contain a follow-set which is a list of terminal +** symbols which are allowed to immediately follow the end of the rule. +** Every configuration is recorded as an instance of the following: */ +struct config { + struct rule *rp; /* The rule upon which the configuration is based */ + int dot; /* The parse point */ + char *fws; /* Follow-set for this configuration only */ + struct plink *fplp; /* Follow-set forward propagation links */ + struct plink *bplp; /* Follow-set backwards propagation links */ + struct state *stp; /* Pointer to state which contains this */ + enum { + COMPLETE, /* The status is used during followset and */ + INCOMPLETE /* shift computations */ + } status; + struct config *next; /* Next configuration in the state */ + struct config *bp; /* The next basis configuration */ +}; + +/* Every shift or reduce operation is stored as one of the following */ +struct action { + struct symbol *sp; /* The look-ahead symbol */ + enum e_action { + SHIFT, + ACCEPT, + REDUCE, + ERROR, + CONFLICT, /* Was a reduce, but part of a conflict */ + SH_RESOLVED, /* Was a shift. Precedence resolved conflict */ + RD_RESOLVED, /* Was reduce. Precedence resolved conflict */ + NOT_USED /* Deleted by compression */ + } type; + union { + struct state *stp; /* The new state, if a shift */ + struct rule *rp; /* The rule, if a reduce */ + } x; + struct action *next; /* Next action for this state */ + struct action *collide; /* Next action with the same hash */ +}; + +/* Each state of the generated parser's finite state machine +** is encoded as an instance of the following structure. */ +struct state { + struct config *bp; /* The basis configurations for this state */ + struct config *cfp; /* All configurations in this set */ + int index; /* Sequencial number for this state */ + struct action *ap; /* Array of actions for this state */ + int naction; /* Number of actions for this state */ + int tabstart; /* First index of the action table */ + int tabdfltact; /* Default action */ +}; + +/* A followset propagation link indicates that the contents of one +** configuration followset should be propagated to another whenever +** the first changes. */ +struct plink { + struct config *cfp; /* The configuration to which linked */ + struct plink *next; /* The next propagate link */ +}; + +/* The state vector for the entire parser generator is recorded as +** follows. (LEMON uses no global variables and makes little use of +** static variables. Fields in the following structure can be thought +** of as begin global variables in the program.) */ +struct lemon { + struct state **sorted; /* Table of states sorted by state number */ + struct rule *rule; /* List of all rules */ + int nstate; /* Number of states */ + int nrule; /* Number of rules */ + int nsymbol; /* Number of terminal and nonterminal symbols */ + int nterminal; /* Number of terminal symbols */ + struct symbol **symbols; /* Sorted array of pointers to symbols */ + int errorcnt; /* Number of errors */ + struct symbol *errsym; /* The error symbol */ + char *name; /* Name of the generated parser */ + char *arg; /* Declaration of the 3th argument to parser */ + char *tokentype; /* Type of terminal symbols in the parser stack */ + char *start; /* Name of the start symbol for the grammar */ + char *stacksize; /* Size of the parser stack */ + char *include; /* Code to put at the start of the C file */ + int includeln; /* Line number for start of include code */ + char *error; /* Code to execute when an error is seen */ + int errorln; /* Line number for start of error code */ + char *overflow; /* Code to execute on a stack overflow */ + int overflowln; /* Line number for start of overflow code */ + char *failure; /* Code to execute on parser failure */ + int failureln; /* Line number for start of failure code */ + char *accept; /* Code to execute when the parser excepts */ + int acceptln; /* Line number for the start of accept code */ + char *extracode; /* Code appended to the generated file */ + int extracodeln; /* Line number for the start of the extra code */ + char *tokendest; /* Code to execute to destroy token data */ + int tokendestln; /* Line number for token destroyer code */ + char *filename; /* Name of the input file */ + char *basename; /* Basename of inputer file (no directory or path */ + char *outname; /* Name of the current output file */ + char *outdirname; /* Name of the output directory, specified by user */ + char *templatename; /* Name of template file to use, specified by user */ + char *tokenprefix; /* A prefix added to token names in the .h file */ + int nconflict; /* Number of parsing conflicts */ + int tablesize; /* Size of the parse tables */ + int basisflag; /* Print only basis configurations */ + char *argv0; /* Name of the program */ +}; + +#define MemoryCheck(X) if((X)==0){ \ + extern void memory_error(); \ + memory_error(); \ +} + +/**************** From the file "table.h" *********************************/ +/* +** All code in this file has been automatically generated +** from a specification in the file +** "table.q" +** by the associative array code building program "aagen". +** Do not edit this file! Instead, edit the specification +** file, then rerun aagen. +*/ +/* +** Code for processing tables in the LEMON parser generator. +*/ + +/* Routines for handling a strings */ + +char *Strsafe(); + +void Strsafe_init(/* void */); +int Strsafe_insert(/* char * */); +char *Strsafe_find(/* char * */); + +/* Routines for handling symbols of the grammar */ + +struct symbol *Symbol_new(); +int Symbolcmpp(/* struct symbol **, struct symbol ** */); +void Symbol_init(/* void */); +int Symbol_insert(/* struct symbol *, char * */); +struct symbol *Symbol_find(/* char * */); +struct symbol *Symbol_Nth(/* int */); +int Symbol_count(/* */); +struct symbol **Symbol_arrayof(/* */); + +/* Routines to manage the state table */ + +int Configcmp(/* struct config *, struct config * */); +struct state *State_new(); +void State_init(/* void */); +int State_insert(/* struct state *, struct config * */); +struct state *State_find(/* struct config * */); +struct state **State_arrayof(/* */); + +/* Routines used for efficiency in Configlist_add */ + +void Configtable_init(/* void */); +int Configtable_insert(/* struct config * */); +struct config *Configtable_find(/* struct config * */); +void Configtable_clear(/* int(*)(struct config *) */); +/****************** From the file "action.c" *******************************/ +/* +** Routines processing parser actions in the LEMON parser generator. +*/ + +/* Allocate a new parser action */ +struct action *Action_new(){ + static struct action *freelist = 0; + struct action *new; + + if( freelist==0 ){ + int i; + int amt = 100; + freelist = (struct action *)malloc( sizeof(struct action)*amt ); + if( freelist==0 ){ + fprintf(stderr,"Unable to allocate memory for a new parser action."); + exit(1); + } + for(i=0; inext; + return new; +} + +/* Compare two actions */ +static int actioncmp(ap1,ap2) +struct action *ap1; +struct action *ap2; +{ + int rc; + rc = ap1->sp->index - ap2->sp->index; + if( rc==0 ) rc = (int)ap1->type - (int)ap2->type; + if( rc==0 ){ + assert( ap1->type==REDUCE && ap2->type==REDUCE ); + rc = ap1->x.rp->index - ap2->x.rp->index; + } + return rc; +} + +/* Sort parser actions */ +struct action *Action_sort(ap) +struct action *ap; +{ + ap = (struct action *)msort(ap,&ap->next,actioncmp); + return ap; +} + +void Action_add(app,type,sp,arg) +struct action **app; +enum e_action type; +struct symbol *sp; +char *arg; +{ + struct action *new; + new = Action_new(); + new->next = *app; + *app = new; + new->type = type; + new->sp = sp; + if( type==SHIFT ){ + new->x.stp = (struct state *)arg; + }else{ + new->x.rp = (struct rule *)arg; + } +} +/********************** From the file "assert.c" ****************************/ +/* +** A more efficient way of handling assertions. +*/ +void myassert(file,line) +char *file; +int line; +{ + fprintf(stderr,"Assertion failed on line %d of file \"%s\"\n",line,file); + exit(1); +} +/********************** From the file "build.c" *****************************/ +/* +** Routines to construction the finite state machine for the LEMON +** parser generator. +*/ + +/* Find a precedence symbol of every rule in the grammar. +** +** Those rules which have a precedence symbol coded in the input +** grammar using the "[symbol]" construct will already have the +** rp->precsym field filled. Other rules take as their precedence +** symbol the first RHS symbol with a defined precedence. If there +** are not RHS symbols with a defined precedence, the precedence +** symbol field is left blank. +*/ +void FindRulePrecedences(xp) +struct lemon *xp; +{ + struct rule *rp; + for(rp=xp->rule; rp; rp=rp->next){ + if( rp->precsym==0 ){ + int i; + for(i=0; inrhs; i++){ + if( rp->rhs[i]->prec>=0 ){ + rp->precsym = rp->rhs[i]; + break; + } + } + } + } + return; +} + +/* Find all nonterminals which will generate the empty string. +** Then go back and compute the first sets of every nonterminal. +** The first set is the set of all terminal symbols which can begin +** a string generated by that nonterminal. +*/ +void FindFirstSets(lemp) +struct lemon *lemp; +{ + int i; + struct rule *rp; + int progress; + + for(i=0; insymbol; i++){ + lemp->symbols[i]->lambda = FALSE; + } + for(i=lemp->nterminal; insymbol; i++){ + lemp->symbols[i]->firstset = SetNew(); + } + + /* First compute all lambdas */ + do{ + progress = 0; + for(rp=lemp->rule; rp; rp=rp->next){ + if( rp->lhs->lambda ) continue; + for(i=0; inrhs; i++){ + if( rp->rhs[i]->lambda==FALSE ) break; + } + if( i==rp->nrhs ){ + rp->lhs->lambda = TRUE; + progress = 1; + } + } + }while( progress ); + + /* Now compute all first sets */ + do{ + struct symbol *s1, *s2; + progress = 0; + for(rp=lemp->rule; rp; rp=rp->next){ + s1 = rp->lhs; + for(i=0; inrhs; i++){ + s2 = rp->rhs[i]; + if( s2->type==TERMINAL ){ + progress += SetAdd(s1->firstset,s2->index); + break; + }else if( s1==s2 ){ + if( s1->lambda==FALSE ) break; + }else{ + progress += SetUnion(s1->firstset,s2->firstset); + if( s2->lambda==FALSE ) break; + } + } + } + }while( progress ); + return; +} + +/* Compute all LR(0) states for the grammar. Links +** are added to between some states so that the LR(1) follow sets +** can be computed later. +*/ +PRIVATE struct state *getstate(/* struct lemon * */); /* forward reference */ +void FindStates(lemp) +struct lemon *lemp; +{ + struct symbol *sp; + struct rule *rp; + + Configlist_init(); + + /* Find the start symbol */ + if( lemp->start ){ + sp = Symbol_find(lemp->start); + if( sp==0 ){ + ErrorMsg(lemp->filename,0, +"The specified start symbol \"%s\" is not \ +in a nonterminal of the grammar. \"%s\" will be used as the start \ +symbol instead.",lemp->start,lemp->rule->lhs->name); + lemp->errorcnt++; + sp = lemp->rule->lhs; + } + }else{ + sp = lemp->rule->lhs; + } + + /* Make sure the start symbol doesn't occur on the right-hand side of + ** any rule. Report an error if it does. (YACC would generate a new + ** start symbol in this case.) */ + for(rp=lemp->rule; rp; rp=rp->next){ + int i; + for(i=0; inrhs; i++){ + if( rp->rhs[i]==sp ){ + ErrorMsg(lemp->filename,0, +"The start symbol \"%s\" occurs on the \ +right-hand side of a rule. This will result in a parser which \ +does not work properly.",sp->name); + lemp->errorcnt++; + } + } + } + + /* The basis configuration set for the first state + ** is all rules which have the start symbol as their + ** left-hand side */ + for(rp=sp->rule; rp; rp=rp->nextlhs){ + struct config *newcfp; + newcfp = Configlist_addbasis(rp,0); + SetAdd(newcfp->fws,0); + } + + /* Compute the first state. All other states will be + ** computed automatically during the computation of the first one. + ** The returned pointer to the first state is not used. */ + (void)getstate(lemp); + return; +} + +/* Return a pointer to a state which is described by the configuration +** list which has been built from calls to Configlist_add. +*/ +PRIVATE void buildshifts(/* struct lemon *, struct state * */); /* Forwd ref */ +PRIVATE struct state *getstate(lemp) +struct lemon *lemp; +{ + struct config *cfp, *bp; + struct state *stp; + + /* Extract the sorted basis of the new state. The basis was constructed + ** by prior calls to "Configlist_addbasis()". */ + Configlist_sortbasis(); + bp = Configlist_basis(); + + /* Get a state with the same basis */ + stp = State_find(bp); + if( stp ){ + /* A state with the same basis already exists! Copy all the follow-set + ** propagation links from the state under construction into the + ** preexisting state, then return a pointer to the preexisting state */ + struct config *x, *y; + for(x=bp, y=stp->bp; x && y; x=x->bp, y=y->bp){ + Plink_copy(&y->bplp,x->bplp); + Plink_delete(x->fplp); + x->fplp = x->bplp = 0; + } + cfp = Configlist_return(); + Configlist_eat(cfp); + }else{ + /* This really is a new state. Construct all the details */ + Configlist_closure(lemp); /* Compute the configuration closure */ + Configlist_sort(); /* Sort the configuration closure */ + cfp = Configlist_return(); /* Get a pointer to the config list */ + stp = State_new(); /* A new state structure */ + MemoryCheck(stp); + stp->bp = bp; /* Remember the configuration basis */ + stp->cfp = cfp; /* Remember the configuration closure */ + stp->index = lemp->nstate++; /* Every state gets a sequence number */ + stp->ap = 0; /* No actions, yet. */ + State_insert(stp,stp->bp); /* Add to the state table */ + buildshifts(lemp,stp); /* Recursively compute successor states */ + } + return stp; +} + +/* Construct all successor states to the given state. A "successor" +** state is any state which can be reached by a shift action. +*/ +PRIVATE void buildshifts(lemp,stp) +struct lemon *lemp; +struct state *stp; /* The state from which successors are computed */ +{ + struct config *cfp; /* For looping thru the config closure of "stp" */ + struct config *bcfp; /* For the inner loop on config closure of "stp" */ + struct config *new; /* */ + struct symbol *sp; /* Symbol following the dot in configuration "cfp" */ + struct symbol *bsp; /* Symbol following the dot in configuration "bcfp" */ + struct state *newstp; /* A pointer to a successor state */ + + /* Each configuration becomes complete after it contibutes to a successor + ** state. Initially, all configurations are incomplete */ + for(cfp=stp->cfp; cfp; cfp=cfp->next) cfp->status = INCOMPLETE; + + /* Loop through all configurations of the state "stp" */ + for(cfp=stp->cfp; cfp; cfp=cfp->next){ + if( cfp->status==COMPLETE ) continue; /* Already used by inner loop */ + if( cfp->dot>=cfp->rp->nrhs ) continue; /* Can't shift this config */ + Configlist_reset(); /* Reset the new config set */ + sp = cfp->rp->rhs[cfp->dot]; /* Symbol after the dot */ + + /* For every configuration in the state "stp" which has the symbol "sp" + ** following its dot, add the same configuration to the basis set under + ** construction but with the dot shifted one symbol to the right. */ + for(bcfp=cfp; bcfp; bcfp=bcfp->next){ + if( bcfp->status==COMPLETE ) continue; /* Already used */ + if( bcfp->dot>=bcfp->rp->nrhs ) continue; /* Can't shift this one */ + bsp = bcfp->rp->rhs[bcfp->dot]; /* Get symbol after dot */ + if( bsp!=sp ) continue; /* Must be same as for "cfp" */ + bcfp->status = COMPLETE; /* Mark this config as used */ + new = Configlist_addbasis(bcfp->rp,bcfp->dot+1); + Plink_add(&new->bplp,bcfp); + } + + /* Get a pointer to the state described by the basis configuration set + ** constructed in the preceding loop */ + newstp = getstate(lemp); + + /* The state "newstp" is reached from the state "stp" by a shift action + ** on the symbol "sp" */ + Action_add(&stp->ap,SHIFT,sp,newstp); + } +} + +/* +** Construct the propagation links +*/ +void FindLinks(lemp) +struct lemon *lemp; +{ + int i; + struct config *cfp, *other; + struct state *stp; + struct plink *plp; + + /* Housekeeping detail: + ** Add to every propagate link a pointer back to the state to + ** which the link is attached. */ + for(i=0; instate; i++){ + stp = lemp->sorted[i]; + for(cfp=stp->cfp; cfp; cfp=cfp->next){ + cfp->stp = stp; + } + } + + /* Convert all backlinks into forward links. Only the forward + ** links are used in the follow-set computation. */ + for(i=0; instate; i++){ + stp = lemp->sorted[i]; + for(cfp=stp->cfp; cfp; cfp=cfp->next){ + for(plp=cfp->bplp; plp; plp=plp->next){ + other = plp->cfp; + Plink_add(&other->fplp,cfp); + } + } + } +} + +/* Compute all followsets. +** +** A followset is the set of all symbols which can come immediately +** after a configuration. +*/ +void FindFollowSets(lemp) +struct lemon *lemp; +{ + int i; + struct config *cfp; + struct plink *plp; + int progress; + int change; + + for(i=0; instate; i++){ + for(cfp=lemp->sorted[i]->cfp; cfp; cfp=cfp->next){ + cfp->status = INCOMPLETE; + } + } + + do{ + progress = 0; + for(i=0; instate; i++){ + for(cfp=lemp->sorted[i]->cfp; cfp; cfp=cfp->next){ + if( cfp->status==COMPLETE ) continue; + for(plp=cfp->fplp; plp; plp=plp->next){ + change = SetUnion(plp->cfp->fws,cfp->fws); + if( change ){ + plp->cfp->status = INCOMPLETE; + progress = 1; + } + } + cfp->status = COMPLETE; + } + } + }while( progress ); +} + +static int resolve_conflict(); + +/* Compute the reduce actions, and resolve conflicts. +*/ +void FindActions(lemp) +struct lemon *lemp; +{ + int i,j; + struct config *cfp; + struct state *stp; + struct symbol *sp; + struct rule *rp; + + /* Add all of the reduce actions + ** A reduce action is added for each element of the followset of + ** a configuration which has its dot at the extreme right. + */ + for(i=0; instate; i++){ /* Loop over all states */ + stp = lemp->sorted[i]; + for(cfp=stp->cfp; cfp; cfp=cfp->next){ /* Loop over all configurations */ + if( cfp->rp->nrhs==cfp->dot ){ /* Is dot at extreme right? */ + for(j=0; jnterminal; j++){ + if( SetFind(cfp->fws,j) ){ + /* Add a reduce action to the state "stp" which will reduce by the + ** rule "cfp->rp" if the lookahead symbol is "lemp->symbols[j]" */ + Action_add(&stp->ap,REDUCE,lemp->symbols[j],cfp->rp); + } + } + } + } + } + + /* Add the accepting token */ + if( lemp->start ){ + sp = Symbol_find(lemp->start); + if( sp==0 ) sp = lemp->rule->lhs; + }else{ + sp = lemp->rule->lhs; + } + /* Add to the first state (which is always the starting state of the + ** finite state machine) an action to ACCEPT if the lookahead is the + ** start nonterminal. */ + Action_add(&lemp->sorted[0]->ap,ACCEPT,sp,0); + + /* Resolve conflicts */ + for(i=0; instate; i++){ + struct action *ap, *nap; + struct state *stp; + stp = lemp->sorted[i]; + assert( stp->ap ); + stp->ap = Action_sort(stp->ap); + for(ap=stp->ap; ap && ap->next; ap=nap){ + for(nap=ap->next; nap && nap->sp==ap->sp; nap=nap->next){ + /* The two actions "ap" and "nap" have the same lookahead. + ** Figure out which one should be used */ + lemp->nconflict += resolve_conflict(ap,nap,lemp->errsym); + } + } + } + + /* Report an error for each rule that can never be reduced. */ + for(rp=lemp->rule; rp; rp=rp->next) rp->canReduce = FALSE; + for(i=0; instate; i++){ + struct action *ap; + for(ap=lemp->sorted[i]->ap; ap; ap=ap->next){ + if( ap->type==REDUCE ) ap->x.rp->canReduce = TRUE; + } + } + for(rp=lemp->rule; rp; rp=rp->next){ + if( rp->canReduce ) continue; + ErrorMsg(lemp->filename,rp->ruleline,"This rule can not be reduced.\n"); + lemp->errorcnt++; + } +} + +/* Resolve a conflict between the two given actions. If the +** conflict can't be resolve, return non-zero. +** +** NO LONGER TRUE: +** To resolve a conflict, first look to see if either action +** is on an error rule. In that case, take the action which +** is not associated with the error rule. If neither or both +** actions are associated with an error rule, then try to +** use precedence to resolve the conflict. +** +** If either action is a SHIFT, then it must be apx. This +** function won't work if apx->type==REDUCE and apy->type==SHIFT. +*/ +static int resolve_conflict(apx,apy,errsym) +struct action *apx; +struct action *apy; +struct symbol *errsym; /* The error symbol (if defined. NULL otherwise) */ +{ + struct symbol *spx, *spy; + int errcnt = 0; + assert( apx->sp==apy->sp ); /* Otherwise there would be no conflict */ + if( apx->type==SHIFT && apy->type==REDUCE ){ + spx = apx->sp; + spy = apy->x.rp->precsym; + if( spy==0 || spx->prec<0 || spy->prec<0 ){ + /* Not enough precedence information. */ + apy->type = CONFLICT; + errcnt++; + }else if( spx->prec>spy->prec ){ /* Lower precedence wins */ + apy->type = RD_RESOLVED; + }else if( spx->precprec ){ + apx->type = SH_RESOLVED; + }else if( spx->prec==spy->prec && spx->assoc==RIGHT ){ /* Use operator */ + apy->type = RD_RESOLVED; /* associativity */ + }else if( spx->prec==spy->prec && spx->assoc==LEFT ){ /* to break tie */ + apx->type = SH_RESOLVED; + }else{ + assert( spx->prec==spy->prec && spx->assoc==NONE ); + apy->type = CONFLICT; + errcnt++; + } + }else if( apx->type==REDUCE && apy->type==REDUCE ){ + spx = apx->x.rp->precsym; + spy = apy->x.rp->precsym; + if( spx==0 || spy==0 || spx->prec<0 || + spy->prec<0 || spx->prec==spy->prec ){ + apy->type = CONFLICT; + errcnt++; + }else if( spx->prec>spy->prec ){ + apy->type = RD_RESOLVED; + }else if( spx->precprec ){ + apx->type = RD_RESOLVED; + } + }else{ + /* Can't happen. Shifts have to come before Reduces on the + ** list because the reduces were added last. Hence, if apx->type==REDUCE + ** then it is impossible for apy->type==SHIFT */ + } + return errcnt; +} +/********************* From the file "configlist.c" *************************/ +/* +** Routines to processing a configuration list and building a state +** in the LEMON parser generator. +*/ + +static struct config *freelist = 0; /* List of free configurations */ +static struct config *current = 0; /* Top of list of configurations */ +static struct config **currentend = 0; /* Last on list of configs */ +static struct config *basis = 0; /* Top of list of basis configs */ +static struct config **basisend = 0; /* End of list of basis configs */ + +/* Return a pointer to a new configuration */ +PRIVATE struct config *newconfig(){ + struct config *new; + if( freelist==0 ){ + int i; + int amt = 3; + freelist = (struct config *)malloc( sizeof(struct config)*amt ); + if( freelist==0 ){ + fprintf(stderr,"Unable to allocate memory for a new configuration."); + exit(1); + } + for(i=0; inext; + return new; +} + +/* The configuration "old" is no longer used */ +PRIVATE void deleteconfig(old) +struct config *old; +{ + old->next = freelist; + freelist = old; +} + +/* Initialized the configuration list builder */ +void Configlist_init(){ + current = 0; + currentend = ¤t; + basis = 0; + basisend = &basis; + Configtable_init(); + return; +} + +/* Initialized the configuration list builder */ +void Configlist_reset(){ + current = 0; + currentend = ¤t; + basis = 0; + basisend = &basis; + Configtable_clear(0); + return; +} + +/* Add another configuration to the configuration list */ +struct config *Configlist_add(rp,dot) +struct rule *rp; /* The rule */ +int dot; /* Index into the RHS of the rule where the dot goes */ +{ + struct config *cfp, model; + + assert( currentend!=0 ); + model.rp = rp; + model.dot = dot; + cfp = Configtable_find(&model); + if( cfp==0 ){ + cfp = newconfig(); + cfp->rp = rp; + cfp->dot = dot; + cfp->fws = SetNew(); + cfp->stp = 0; + cfp->fplp = cfp->bplp = 0; + cfp->next = 0; + cfp->bp = 0; + *currentend = cfp; + currentend = &cfp->next; + Configtable_insert(cfp); + } + return cfp; +} + +/* Add a basis configuration to the configuration list */ +struct config *Configlist_addbasis(rp,dot) +struct rule *rp; +int dot; +{ + struct config *cfp, model; + + assert( basisend!=0 ); + assert( currentend!=0 ); + model.rp = rp; + model.dot = dot; + cfp = Configtable_find(&model); + if( cfp==0 ){ + cfp = newconfig(); + cfp->rp = rp; + cfp->dot = dot; + cfp->fws = SetNew(); + cfp->stp = 0; + cfp->fplp = cfp->bplp = 0; + cfp->next = 0; + cfp->bp = 0; + *currentend = cfp; + currentend = &cfp->next; + *basisend = cfp; + basisend = &cfp->bp; + Configtable_insert(cfp); + } + return cfp; +} + +/* Compute the closure of the configuration list */ +void Configlist_closure(lemp) +struct lemon *lemp; +{ + struct config *cfp, *newcfp; + struct rule *rp, *newrp; + struct symbol *sp, *xsp; + int i, dot; + + assert( currentend!=0 ); + for(cfp=current; cfp; cfp=cfp->next){ + rp = cfp->rp; + dot = cfp->dot; + if( dot>=rp->nrhs ) continue; + sp = rp->rhs[dot]; + if( sp->type==NONTERMINAL ){ + if( sp->rule==0 && sp!=lemp->errsym ){ + ErrorMsg(lemp->filename,rp->line,"Nonterminal \"%s\" has no rules.", + sp->name); + lemp->errorcnt++; + } + for(newrp=sp->rule; newrp; newrp=newrp->nextlhs){ + newcfp = Configlist_add(newrp,0); + for(i=dot+1; inrhs; i++){ + xsp = rp->rhs[i]; + if( xsp->type==TERMINAL ){ + SetAdd(newcfp->fws,xsp->index); + break; + }else{ + SetUnion(newcfp->fws,xsp->firstset); + if( xsp->lambda==FALSE ) break; + } + } + if( i==rp->nrhs ) Plink_add(&cfp->fplp,newcfp); + } + } + } + return; +} + +/* Sort the configuration list */ +void Configlist_sort(){ + current = (struct config *)msort(current,&(current->next),Configcmp); + currentend = 0; + return; +} + +/* Sort the basis configuration list */ +void Configlist_sortbasis(){ + basis = (struct config *)msort(current,&(current->bp),Configcmp); + basisend = 0; + return; +} + +/* Return a pointer to the head of the configuration list and +** reset the list */ +struct config *Configlist_return(){ + struct config *old; + old = current; + current = 0; + currentend = 0; + return old; +} + +/* Return a pointer to the head of the configuration list and +** reset the list */ +struct config *Configlist_basis(){ + struct config *old; + old = basis; + basis = 0; + basisend = 0; + return old; +} + +/* Free all elements of the given configuration list */ +void Configlist_eat(cfp) +struct config *cfp; +{ + struct config *nextcfp; + for(; cfp; cfp=nextcfp){ + nextcfp = cfp->next; + assert( cfp->fplp==0 ); + assert( cfp->bplp==0 ); + if( cfp->fws ) SetFree(cfp->fws); + deleteconfig(cfp); + } + return; +} +/***************** From the file "error.c" *********************************/ +/* +** Code for printing error message. +*/ + +/* Find a good place to break "msg" so that its length is at least "min" +** but no more than "max". Make the point as close to max as possible. +*/ +static int findbreak(msg,min,max) +char *msg; +int min; +int max; +{ + int i,spot; + char c; + for(i=spot=min; i<=max; i++){ + c = msg[i]; + if( c=='\t' ) msg[i] = ' '; + if( c=='\n' ){ msg[i] = ' '; spot = i; break; } + if( c==0 ){ spot = i; break; } + if( c=='-' && i0 ){ + sprintf(prefix,"%.*s:%d: ",PREFIXLIMIT-10,filename,lineno); + }else{ + sprintf(prefix,"%.*s: ",PREFIXLIMIT-10,filename); + } + prefixsize = strlen(prefix); + availablewidth = LINEWIDTH - prefixsize; + + /* Generate the error message */ + vsprintf(errmsg,format,ap); + va_end(ap); + errmsgsize = strlen(errmsg); + /* Remove trailing '\n's from the error message. */ + while( errmsgsize>0 && errmsg[errmsgsize-1]=='\n' ){ + errmsg[--errmsgsize] = 0; + } + + /* Print the error message */ + base = 0; + while( errmsg[base]!=0 ){ + end = restart = findbreak(&errmsg[base],0,availablewidth); + restart += base; + while( errmsg[restart]==' ' ) restart++; + fprintf(stdout,"%s%.*s\n",prefix,end,&errmsg[base]); + base = restart; + } +} +/**************** From the file "main.c" ************************************/ +/* +** Main program file for the LEMON parser generator. +*/ + +/* Report an out-of-memory condition and abort. This function +** is used mostly by the "MemoryCheck" macro in struct.h +*/ +void memory_error(){ + fprintf(stderr,"Out of memory. Aborting...\n"); + exit(1); +} + +/* Locates the basename in a string possibly containing paths, + * including forward-slash and backward-slash delimiters on Windows, + * and allocates a new string containing just the basename. + * Returns the pointer to that string. + */ +PRIVATE char* +make_basename(char* fullname) +{ + char *cp; + char *new_string; + + /* Find the last forward slash */ + cp = strrchr(fullname, '/'); + +#ifdef WIN32 + /* On Windows, if no forward slash was found, look ofr + * backslash also */ + if (!cp) + cp = strrchr(fullname, '\\'); +#endif + + if (!cp) { + new_string = malloc( strlen(fullname) ); + strcpy(new_string, fullname); + } + else { + /* skip the slash */ + cp++; + new_string = malloc( strlen(cp) ); + strcpy(new_string, cp); + } + + return new_string; +} + + + + +/* The main program. Parse the command line and do it... */ +int main(argc,argv) +int argc; +char **argv; +{ + static int version = 0; + static int rpflag = 0; + static int basisflag = 0; + static int compress = 0; + static int quiet = 0; + static int statistics = 0; + static int mhflag = 0; + static char *outdirname = NULL; + static char *templatename = NULL; + static struct s_options options[] = { + {OPT_FLAG, "b", (char*)&basisflag, "Print only the basis in report."}, + {OPT_FLAG, "c", (char*)&compress, "Don't compress the action table."}, + {OPT_STR, "d", (char*)&outdirname, "Output directory name."}, + {OPT_FLAG, "g", (char*)&rpflag, "Print grammar without actions."}, + {OPT_FLAG, "m", (char*)&mhflag, "Output a makeheaders compatible file"}, + {OPT_FLAG, "q", (char*)&quiet, "(Quiet) Don't print the report file."}, + {OPT_FLAG, "s", (char*)&statistics, "Print parser stats to standard output."}, + {OPT_STR, "t", (char*)&templatename, "Template file to use."}, + {OPT_FLAG, "x", (char*)&version, "Print the version number."}, + {OPT_FLAG,0,0,0} + }; + int i; + struct lemon lem; + + optinit(argv,options,stderr); + if( version ){ + printf("Lemon version 1.0\n" + "Copyright 1991-1997 by D. Richard Hipp\n" + "Freely distributable under the GNU Public License.\n" + ); + exit(0); + } + if( optnargs()!=1 ){ + fprintf(stderr,"Exactly one filename argument is required.\n"); + exit(1); + } + lem.errorcnt = 0; + + /* Initialize the machine */ + Strsafe_init(); + Symbol_init(); + State_init(); + lem.argv0 = argv[0]; + lem.filename = optarg(0); + lem.basisflag = basisflag; + lem.nconflict = 0; + lem.name = lem.include = lem.arg = lem.tokentype = lem.start = 0; + lem.stacksize = 0; + lem.error = lem.overflow = lem.failure = lem.accept = lem.tokendest = + lem.tokenprefix = lem.outname = lem.extracode = 0; + lem.tablesize = 0; + Symbol_new("$"); + lem.errsym = Symbol_new("error"); + lem.outdirname = outdirname; + lem.templatename = templatename; + lem.basename = make_basename(lem.filename); + + /* Parse the input file */ + Parse(&lem); + if( lem.errorcnt ) exit(lem.errorcnt); + if( lem.rule==0 ){ + fprintf(stderr,"Empty grammar.\n"); + exit(1); + } + + /* Count and index the symbols of the grammar */ + lem.nsymbol = Symbol_count(); + Symbol_new("{default}"); + lem.symbols = Symbol_arrayof(); + qsort(lem.symbols,lem.nsymbol+1,sizeof(struct symbol*), + (int(*)())Symbolcmpp); + for(i=0; i<=lem.nsymbol; i++) lem.symbols[i]->index = i; + for(i=1; isupper(lem.symbols[i]->name[0]); i++); + lem.nterminal = i; + + /* Generate a reprint of the grammar, if requested on the command line */ + if( rpflag ){ + Reprint(&lem); + }else{ + /* Initialize the size for all follow and first sets */ + SetSize(lem.nterminal); + + /* Find the precedence for every production rule (that has one) */ + FindRulePrecedences(&lem); + + /* Compute the lambda-nonterminals and the first-sets for every + ** nonterminal */ + FindFirstSets(&lem); + + /* Compute all LR(0) states. Also record follow-set propagation + ** links so that the follow-set can be computed later */ + lem.nstate = 0; + FindStates(&lem); + lem.sorted = State_arrayof(); + + /* Tie up loose ends on the propagation links */ + FindLinks(&lem); + + /* Compute the follow set of every reducible configuration */ + FindFollowSets(&lem); + + /* Compute the action tables */ + FindActions(&lem); + + /* Compress the action tables */ + if( compress==0 ) CompressTables(&lem); + + /* Generate a report of the parser generated. (the "y.output" file) */ + if( !quiet ) ReportOutput(&lem); + + /* Generate the source code for the parser */ + ReportTable(&lem, mhflag); + + /* Produce a header file for use by the scanner. (This step is + ** omitted if the "-m" option is used because makeheaders will + ** generate the file for us.) */ + if( !mhflag ) ReportHeader(&lem); + } + if( statistics ){ + printf("Parser statistics: %d terminals, %d nonterminals, %d rules\n", + lem.nterminal, lem.nsymbol - lem.nterminal, lem.nrule); + printf(" %d states, %d parser table entries, %d conflicts\n", + lem.nstate, lem.tablesize, lem.nconflict); + } + if( lem.nconflict ){ + fprintf(stderr,"%d parsing conflicts.\n",lem.nconflict); + } + exit(lem.errorcnt + lem.nconflict); +} +/******************** From the file "msort.c" *******************************/ +/* +** A generic merge-sort program. +** +** USAGE: +** Let "ptr" be a pointer to some structure which is at the head of +** a null-terminated list. Then to sort the list call: +** +** ptr = msort(ptr,&(ptr->next),cmpfnc); +** +** In the above, "cmpfnc" is a pointer to a function which compares +** two instances of the structure and returns an integer, as in +** strcmp. The second argument is a pointer to the pointer to the +** second element of the linked list. This address is used to compute +** the offset to the "next" field within the structure. The offset to +** the "next" field must be constant for all structures in the list. +** +** The function returns a new pointer which is the head of the list +** after sorting. +** +** ALGORITHM: +** Merge-sort. +*/ + +/* +** Return a pointer to the next structure in the linked list. +*/ +#define NEXT(A) (*(char**)(((int)A)+offset)) + +/* +** Inputs: +** a: A sorted, null-terminated linked list. (May be null). +** b: A sorted, null-terminated linked list. (May be null). +** cmp: A pointer to the comparison function. +** offset: Offset in the structure to the "next" field. +** +** Return Value: +** A pointer to the head of a sorted list containing the elements +** of both a and b. +** +** Side effects: +** The "next" pointers for elements in the lists a and b are +** changed. +*/ +static char *merge(a,b,cmp,offset) +char *a; +char *b; +int (*cmp)(); +int offset; +{ + char *ptr, *head; + + if( a==0 ){ + head = b; + }else if( b==0 ){ + head = a; + }else{ + if( (*cmp)(a,b)<0 ){ + ptr = a; + a = NEXT(a); + }else{ + ptr = b; + b = NEXT(b); + } + head = ptr; + while( a && b ){ + if( (*cmp)(a,b)<0 ){ + NEXT(ptr) = a; + ptr = a; + a = NEXT(a); + }else{ + NEXT(ptr) = b; + ptr = b; + b = NEXT(b); + } + } + if( a ) NEXT(ptr) = a; + else NEXT(ptr) = b; + } + return head; +} + +/* +** Inputs: +** list: Pointer to a singly-linked list of structures. +** next: Pointer to pointer to the second element of the list. +** cmp: A comparison function. +** +** Return Value: +** A pointer to the head of a sorted list containing the elements +** orginally in list. +** +** Side effects: +** The "next" pointers for elements in list are changed. +*/ +#define LISTSIZE 30 +char *msort(list,next,cmp) +char *list; +char **next; +int (*cmp)(); +{ + int offset; + char *ep; + char *set[LISTSIZE]; + int i; + offset = (int)next - (int)list; + for(i=0; istate = WAITING_FOR_DECL_KEYWORD; + }else if( islower(x[0]) ){ + psp->lhs = Symbol_new(x); + psp->nrhs = 0; + psp->lhsalias = 0; + psp->state = WAITING_FOR_ARROW; + }else if( x[0]=='{' ){ + if( psp->prevrule==0 ){ + ErrorMsg(psp->filename,psp->tokenlineno, +"There is not prior rule opon which to attach the code \ +fragment which begins on this line."); + psp->errorcnt++; + }else if( psp->prevrule->code!=0 ){ + ErrorMsg(psp->filename,psp->tokenlineno, +"Code fragment beginning on this line is not the first \ +to follow the previous rule."); + psp->errorcnt++; + }else{ + psp->prevrule->line = psp->tokenlineno; + psp->prevrule->code = &x[1]; + } + }else if( x[0]=='[' ){ + psp->state = PRECEDENCE_MARK_1; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Token \"%s\" should be either \"%%\" or a nonterminal name.", + x); + psp->errorcnt++; + } + break; + case PRECEDENCE_MARK_1: + if( !isupper(x[0]) ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "The precedence symbol must be a terminal."); + psp->errorcnt++; + }else if( psp->prevrule==0 ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "There is no prior rule to assign precedence \"[%s]\".",x); + psp->errorcnt++; + }else if( psp->prevrule->precsym!=0 ){ + ErrorMsg(psp->filename,psp->tokenlineno, +"Precedence mark on this line is not the first \ +to follow the previous rule."); + psp->errorcnt++; + }else{ + psp->prevrule->precsym = Symbol_new(x); + } + psp->state = PRECEDENCE_MARK_2; + break; + case PRECEDENCE_MARK_2: + if( x[0]!=']' ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "Missing \"]\" on precedence mark."); + psp->errorcnt++; + } + psp->state = WAITING_FOR_DECL_OR_RULE; + break; + case WAITING_FOR_ARROW: + if( x[0]==':' && x[1]==':' && x[2]=='=' ){ + psp->state = IN_RHS; + }else if( x[0]=='(' ){ + psp->state = LHS_ALIAS_1; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Expected to see a \":\" following the LHS symbol \"%s\".", + psp->lhs->name); + psp->errorcnt++; + psp->state = RESYNC_AFTER_RULE_ERROR; + } + break; + case LHS_ALIAS_1: + if( isalpha(x[0]) ){ + psp->lhsalias = x; + psp->state = LHS_ALIAS_2; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "\"%s\" is not a valid alias for the LHS \"%s\"\n", + x,psp->lhs->name); + psp->errorcnt++; + psp->state = RESYNC_AFTER_RULE_ERROR; + } + break; + case LHS_ALIAS_2: + if( x[0]==')' ){ + psp->state = LHS_ALIAS_3; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Missing \")\" following LHS alias name \"%s\".",psp->lhsalias); + psp->errorcnt++; + psp->state = RESYNC_AFTER_RULE_ERROR; + } + break; + case LHS_ALIAS_3: + if( x[0]==':' && x[1]==':' && x[2]=='=' ){ + psp->state = IN_RHS; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Missing \"->\" following: \"%s(%s)\".", + psp->lhs->name,psp->lhsalias); + psp->errorcnt++; + psp->state = RESYNC_AFTER_RULE_ERROR; + } + break; + case IN_RHS: + if( x[0]=='.' ){ + struct rule *rp; + rp = (struct rule *)malloc( sizeof(struct rule) + + sizeof(struct symbol*)*psp->nrhs + sizeof(char*)*psp->nrhs ); + if( rp==0 ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "Can't allocate enough memory for this rule."); + psp->errorcnt++; + psp->prevrule = 0; + }else{ + int i; + rp->ruleline = psp->tokenlineno; + rp->rhs = (struct symbol**)&rp[1]; + rp->rhsalias = (char**)&(rp->rhs[psp->nrhs]); + for(i=0; inrhs; i++){ + rp->rhs[i] = psp->rhs[i]; + rp->rhsalias[i] = psp->alias[i]; + } + rp->lhs = psp->lhs; + rp->lhsalias = psp->lhsalias; + rp->nrhs = psp->nrhs; + rp->code = 0; + rp->precsym = 0; + rp->index = psp->gp->nrule++; + rp->nextlhs = rp->lhs->rule; + rp->lhs->rule = rp; + rp->next = 0; + if( psp->firstrule==0 ){ + psp->firstrule = psp->lastrule = rp; + }else{ + psp->lastrule->next = rp; + psp->lastrule = rp; + } + psp->prevrule = rp; + } + psp->state = WAITING_FOR_DECL_OR_RULE; + }else if( isalpha(x[0]) ){ + if( psp->nrhs>=MAXRHS ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "Too many symbol on RHS or rule beginning at \"%s\".", + x); + psp->errorcnt++; + psp->state = RESYNC_AFTER_RULE_ERROR; + }else{ + psp->rhs[psp->nrhs] = Symbol_new(x); + psp->alias[psp->nrhs] = 0; + psp->nrhs++; + } + }else if( x[0]=='(' && psp->nrhs>0 ){ + psp->state = RHS_ALIAS_1; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Illegal character on RHS of rule: \"%s\".",x); + psp->errorcnt++; + psp->state = RESYNC_AFTER_RULE_ERROR; + } + break; + case RHS_ALIAS_1: + if( isalpha(x[0]) ){ + psp->alias[psp->nrhs-1] = x; + psp->state = RHS_ALIAS_2; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "\"%s\" is not a valid alias for the RHS symbol \"%s\"\n", + x,psp->rhs[psp->nrhs-1]->name); + psp->errorcnt++; + psp->state = RESYNC_AFTER_RULE_ERROR; + } + break; + case RHS_ALIAS_2: + if( x[0]==')' ){ + psp->state = IN_RHS; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Missing \")\" following LHS alias name \"%s\".",psp->lhsalias); + psp->errorcnt++; + psp->state = RESYNC_AFTER_RULE_ERROR; + } + break; + case WAITING_FOR_DECL_KEYWORD: + if( isalpha(x[0]) ){ + psp->declkeyword = x; + psp->declargslot = 0; + psp->decllnslot = 0; + psp->state = WAITING_FOR_DECL_ARG; + if( strcmp(x,"name")==0 ){ + psp->declargslot = &(psp->gp->name); + }else if( strcmp(x,"include")==0 ){ + psp->declargslot = &(psp->gp->include); + psp->decllnslot = &psp->gp->includeln; + }else if( strcmp(x,"code")==0 ){ + psp->declargslot = &(psp->gp->extracode); + psp->decllnslot = &psp->gp->extracodeln; + }else if( strcmp(x,"token_destructor")==0 ){ + psp->declargslot = &psp->gp->tokendest; + psp->decllnslot = &psp->gp->tokendestln; + }else if( strcmp(x,"token_prefix")==0 ){ + psp->declargslot = &psp->gp->tokenprefix; + }else if( strcmp(x,"syntax_error")==0 ){ + psp->declargslot = &(psp->gp->error); + psp->decllnslot = &psp->gp->errorln; + }else if( strcmp(x,"parse_accept")==0 ){ + psp->declargslot = &(psp->gp->accept); + psp->decllnslot = &psp->gp->acceptln; + }else if( strcmp(x,"parse_failure")==0 ){ + psp->declargslot = &(psp->gp->failure); + psp->decllnslot = &psp->gp->failureln; + }else if( strcmp(x,"stack_overflow")==0 ){ + psp->declargslot = &(psp->gp->overflow); + psp->decllnslot = &psp->gp->overflowln; + }else if( strcmp(x,"extra_argument")==0 ){ + psp->declargslot = &(psp->gp->arg); + }else if( strcmp(x,"token_type")==0 ){ + psp->declargslot = &(psp->gp->tokentype); + }else if( strcmp(x,"stack_size")==0 ){ + psp->declargslot = &(psp->gp->stacksize); + }else if( strcmp(x,"start_symbol")==0 ){ + psp->declargslot = &(psp->gp->start); + }else if( strcmp(x,"left")==0 ){ + psp->preccounter++; + psp->declassoc = LEFT; + psp->state = WAITING_FOR_PRECEDENCE_SYMBOL; + }else if( strcmp(x,"right")==0 ){ + psp->preccounter++; + psp->declassoc = RIGHT; + psp->state = WAITING_FOR_PRECEDENCE_SYMBOL; + }else if( strcmp(x,"nonassoc")==0 ){ + psp->preccounter++; + psp->declassoc = NONE; + psp->state = WAITING_FOR_PRECEDENCE_SYMBOL; + }else if( strcmp(x,"destructor")==0 ){ + psp->state = WAITING_FOR_DESTRUCTOR_SYMBOL; + }else if( strcmp(x,"type")==0 ){ + psp->state = WAITING_FOR_DATATYPE_SYMBOL; + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Unknown declaration keyword: \"%%%s\".",x); + psp->errorcnt++; + psp->state = RESYNC_AFTER_DECL_ERROR; + } + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Illegal declaration keyword: \"%s\".",x); + psp->errorcnt++; + psp->state = RESYNC_AFTER_DECL_ERROR; + } + break; + case WAITING_FOR_DESTRUCTOR_SYMBOL: + if( !isalpha(x[0]) ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "Symbol name missing after %destructor keyword"); + psp->errorcnt++; + psp->state = RESYNC_AFTER_DECL_ERROR; + }else{ + struct symbol *sp = Symbol_new(x); + psp->declargslot = &sp->destructor; + psp->decllnslot = &sp->destructorln; + psp->state = WAITING_FOR_DECL_ARG; + } + break; + case WAITING_FOR_DATATYPE_SYMBOL: + if( !isalpha(x[0]) ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "Symbol name missing after %destructor keyword"); + psp->errorcnt++; + psp->state = RESYNC_AFTER_DECL_ERROR; + }else{ + struct symbol *sp = Symbol_new(x); + psp->declargslot = &sp->datatype; + psp->decllnslot = 0; + psp->state = WAITING_FOR_DECL_ARG; + } + break; + case WAITING_FOR_PRECEDENCE_SYMBOL: + if( x[0]=='.' ){ + psp->state = WAITING_FOR_DECL_OR_RULE; + }else if( isupper(x[0]) ){ + struct symbol *sp; + sp = Symbol_new(x); + if( sp->prec>=0 ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "Symbol \"%s\" has already be given a precedence.",x); + psp->errorcnt++; + }else{ + sp->prec = psp->preccounter; + sp->assoc = psp->declassoc; + } + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Can't assign a precedence to \"%s\".",x); + psp->errorcnt++; + } + break; + case WAITING_FOR_DECL_ARG: + if( (x[0]=='{' || x[0]=='\"' || isalnum(x[0])) ){ + if( *(psp->declargslot)!=0 ){ + ErrorMsg(psp->filename,psp->tokenlineno, + "The argument \"%s\" to declaration \"%%%s\" is not the first.", + x[0]=='\"' ? &x[1] : x,psp->declkeyword); + psp->errorcnt++; + psp->state = RESYNC_AFTER_DECL_ERROR; + }else{ + *(psp->declargslot) = (x[0]=='\"' || x[0]=='{') ? &x[1] : x; + if( psp->decllnslot ) *psp->decllnslot = psp->tokenlineno; + psp->state = WAITING_FOR_DECL_OR_RULE; + } + }else{ + ErrorMsg(psp->filename,psp->tokenlineno, + "Illegal argument to %%%s: %s",psp->declkeyword,x); + psp->errorcnt++; + psp->state = RESYNC_AFTER_DECL_ERROR; + } + break; + case RESYNC_AFTER_RULE_ERROR: +/* if( x[0]=='.' ) psp->state = WAITING_FOR_DECL_OR_RULE; +** break; */ + case RESYNC_AFTER_DECL_ERROR: + if( x[0]=='.' ) psp->state = WAITING_FOR_DECL_OR_RULE; + if( x[0]=='%' ) psp->state = WAITING_FOR_DECL_KEYWORD; + break; + } +} + +/* In spite of its name, this function is really a scanner. It read +** in the entire input file (all at once) then tokenizes it. Each +** token is passed to the function "parseonetoken" which builds all +** the appropriate data structures in the global state vector "gp". +*/ +void Parse(gp) +struct lemon *gp; +{ + struct pstate ps; + FILE *fp; + char *filebuf; + int filesize; + int lineno; + int c; + char *cp, *nextcp; + int startline = 0; + + ps.gp = gp; + ps.filename = gp->filename; + ps.errorcnt = 0; + ps.state = INITIALIZE; + + /* Begin by reading the input file */ + fp = fopen(ps.filename,"rb"); + if( fp==0 ){ + ErrorMsg(ps.filename,0,"Can't open this file for reading."); + gp->errorcnt++; + return; + } + fseek(fp,0,2); + filesize = ftell(fp); + rewind(fp); + filebuf = (char *)malloc( filesize+1 ); + if( filebuf==0 ){ + ErrorMsg(ps.filename,0,"Can't allocate %d of memory to hold this file.", + filesize+1); + gp->errorcnt++; + return; + } + if( fread(filebuf,1,filesize,fp)!=filesize ){ + ErrorMsg(ps.filename,0,"Can't read in all %d bytes of this file.", + filesize); + free(filebuf); + gp->errorcnt++; + return; + } + fclose(fp); + filebuf[filesize] = 0; + + /* Now scan the text of the input file */ + lineno = 1; + for(cp=filebuf; (c= *cp)!=0; ){ + if( c=='\n' ) lineno++; /* Keep track of the line number */ + if( isspace(c) ){ cp++; continue; } /* Skip all white space */ + if( c=='/' && cp[1]=='/' ){ /* Skip C++ style comments */ + cp+=2; + while( (c= *cp)!=0 && c!='\n' ) cp++; + continue; + } + if( c=='/' && cp[1]=='*' ){ /* Skip C style comments */ + cp+=2; + while( (c= *cp)!=0 && (c!='/' || cp[-1]!='*') ){ + if( c=='\n' ) lineno++; + cp++; + } + if( c ) cp++; + continue; + } + ps.tokenstart = cp; /* Mark the beginning of the token */ + ps.tokenlineno = lineno; /* Linenumber on which token begins */ + if( c=='\"' ){ /* String literals */ + cp++; + while( (c= *cp)!=0 && c!='\"' ){ + if( c=='\n' ) lineno++; + cp++; + } + if( c==0 ){ + ErrorMsg(ps.filename,startline, +"String starting on this line is not terminated before the end of the file."); + ps.errorcnt++; + nextcp = cp; + }else{ + nextcp = cp+1; + } + }else if( c=='{' ){ /* A block of C code */ + int level; + cp++; + for(level=1; (c= *cp)!=0 && (level>1 || c!='}'); cp++){ + if( c=='\n' ) lineno++; + else if( c=='{' ) level++; + else if( c=='}' ) level--; + else if( c=='/' && cp[1]=='*' ){ /* Skip comments */ + int prevc; + cp = &cp[2]; + prevc = 0; + while( (c= *cp)!=0 && (c!='/' || prevc!='*') ){ + if( c=='\n' ) lineno++; + prevc = c; + cp++; + } + }else if( c=='/' && cp[1]=='/' ){ /* Skip C++ style comments too */ + cp = &cp[2]; + while( (c= *cp)!=0 && c!='\n' ) cp++; + if( c ) lineno++; + }else if( c=='\'' || c=='\"' ){ /* String a character literals */ + int startchar, prevc; + startchar = c; + prevc = 0; + for(cp++; (c= *cp)!=0 && (c!=startchar || prevc=='\\'); cp++){ + if( c=='\n' ) lineno++; + if( prevc=='\\' ) prevc = 0; + else prevc = c; + } + } + } + if( c==0 ){ + ErrorMsg(ps.filename,startline, +"C code starting on this line is not terminated before the end of the file."); + ps.errorcnt++; + nextcp = cp; + }else{ + nextcp = cp+1; + } + }else if( isalnum(c) ){ /* Identifiers */ + while( (c= *cp)!=0 && (isalnum(c) || c=='_') ) cp++; + nextcp = cp; + }else if( c==':' && cp[1]==':' && cp[2]=='=' ){ /* The operator "::=" */ + cp += 3; + nextcp = cp; + }else{ /* All other (one character) operators */ + cp++; + nextcp = cp; + } + c = *cp; + *cp = 0; /* Null terminate the token */ + parseonetoken(&ps); /* Parse the token */ + *cp = c; /* Restore the buffer */ + cp = nextcp; + } + free(filebuf); /* Release the buffer after parsing */ + gp->rule = ps.firstrule; + gp->errorcnt = ps.errorcnt; +} +/*************************** From the file "plink.c" *********************/ +/* +** Routines processing configuration follow-set propagation links +** in the LEMON parser generator. +*/ +static struct plink *plink_freelist = 0; + +/* Allocate a new plink */ +struct plink *Plink_new(){ + struct plink *new; + + if( plink_freelist==0 ){ + int i; + int amt = 100; + plink_freelist = (struct plink *)malloc( sizeof(struct plink)*amt ); + if( plink_freelist==0 ){ + fprintf(stderr, + "Unable to allocate memory for a new follow-set propagation link.\n"); + exit(1); + } + for(i=0; inext; + return new; +} + +/* Add a plink to a plink list */ +void Plink_add(plpp,cfp) +struct plink **plpp; +struct config *cfp; +{ + struct plink *new; + new = Plink_new(); + new->next = *plpp; + *plpp = new; + new->cfp = cfp; +} + +/* Transfer every plink on the list "from" to the list "to" */ +void Plink_copy(to,from) +struct plink **to; +struct plink *from; +{ + struct plink *nextpl; + while( from ){ + nextpl = from->next; + from->next = *to; + *to = from; + from = nextpl; + } +} + +/* Delete every plink on the list */ +void Plink_delete(plp) +struct plink *plp; +{ + struct plink *nextpl; + + while( plp ){ + nextpl = plp->next; + plp->next = plink_freelist; + plink_freelist = plp; + plp = nextpl; + } +} +/*********************** From the file "report.c" **************************/ +/* +** Procedures for generating reports and tables in the LEMON parser generator. +*/ + +/* Generate a filename with the given suffix. Space to hold the +** name comes from malloc() and must be freed by the calling +** function. +*/ +PRIVATE char *file_makename(pattern,suffix) +char *pattern; +char *suffix; +{ + char *name; + char *cp; + + name = malloc( strlen(pattern) + strlen(suffix) + 5 ); + if( name==0 ){ + fprintf(stderr,"Can't allocate space for a filename.\n"); + exit(1); + } + strcpy(name,pattern); + cp = strrchr(name,'.'); + if( cp ) *cp = 0; + strcat(name,suffix); + return name; +} + +/* Generate a filename with the given suffix. Uses only +** the basename of the input file, not the entire path. This +** is useful for creating output files when using outdirname. +** Space to hold this name comes from malloc() and must be +** freed by the calling function. +*/ +PRIVATE char *file_makename_using_basename(lemp,suffix) +struct lemon *lemp; +char *suffix; +{ + return file_makename(lemp->basename, suffix); +} + +/* Open a file with a name based on the name of the input file, +** but with a different (specified) suffix, and return a pointer +** to the stream. Prepend outdirname for both reads and writes, because +** the only time we read is when checking for an already-produced +** header file, which should exist in the output directory, not the +** input directory. If we ever need to file_open(,,"r") on the input +** side, we should add another arg to file_open() indicating which +** directory, ("input, "output", or "other") we should deal with. +*/ +PRIVATE FILE *file_open(lemp,suffix,mode) +struct lemon *lemp; +char *suffix; +char *mode; +{ + FILE *fp; + char *name; + + if( lemp->outname ) free(lemp->outname); + name = file_makename_using_basename(lemp, suffix); + + if ( lemp->outdirname != NULL ) { + lemp->outname = malloc( strlen(lemp->outdirname) + strlen(name) + 2); + if ( lemp->outname == 0 ) { + fprintf(stderr, "Can't allocate space for dir/filename"); + exit(1); + } + strcpy(lemp->outname, lemp->outdirname); +#ifdef __WIN32__ + strcat(lemp->outname, "\\"); +#else + strcat(lemp->outname, "/"); +#endif + strcat(lemp->outname, name); + free(name); + } + else { + lemp->outname = name; + } + + fp = fopen(lemp->outname,mode); + if( fp==0 && *mode=='w' ){ + fprintf(stderr,"Can't open file \"%s\".\n",lemp->outname); + lemp->errorcnt++; + return 0; + } + return fp; +} + +/* Duplicate the input file without comments and without actions +** on rules */ +void Reprint(lemp) +struct lemon *lemp; +{ + struct rule *rp; + struct symbol *sp; + int i, j, maxlen, len, ncolumns, skip; + printf("// Reprint of input file \"%s\".\n// Symbols:\n",lemp->filename); + maxlen = 10; + for(i=0; insymbol; i++){ + sp = lemp->symbols[i]; + len = strlen(sp->name); + if( len>maxlen ) maxlen = len; + } + ncolumns = 76/(maxlen+5); + if( ncolumns<1 ) ncolumns = 1; + skip = (lemp->nsymbol + ncolumns - 1)/ncolumns; + for(i=0; insymbol; j+=skip){ + sp = lemp->symbols[j]; + assert( sp->index==j ); + printf(" %3d %-*.*s",j,maxlen,maxlen,sp->name); + } + printf("\n"); + } + for(rp=lemp->rule; rp; rp=rp->next){ + printf("%s",rp->lhs->name); +/* if( rp->lhsalias ) printf("(%s)",rp->lhsalias); */ + printf(" ::="); + for(i=0; inrhs; i++){ + printf(" %s",rp->rhs[i]->name); +/* if( rp->rhsalias[i] ) printf("(%s)",rp->rhsalias[i]); */ + } + printf("."); + if( rp->precsym ) printf(" [%s]",rp->precsym->name); +/* if( rp->code ) printf("\n %s",rp->code); */ + printf("\n"); + } +} + +void ConfigPrint(fp,cfp) +FILE *fp; +struct config *cfp; +{ + struct rule *rp; + int i; + rp = cfp->rp; + fprintf(fp,"%s ::=",rp->lhs->name); + for(i=0; i<=rp->nrhs; i++){ + if( i==cfp->dot ) fprintf(fp," *"); + if( i==rp->nrhs ) break; + fprintf(fp," %s",rp->rhs[i]->name); + } +} + +/* #define TEST */ +#ifdef TEST +/* Print a set */ +PRIVATE void SetPrint(out,set,lemp) +FILE *out; +char *set; +struct lemon *lemp; +{ + int i; + char *spacer; + spacer = ""; + fprintf(out,"%12s[",""); + for(i=0; interminal; i++){ + if( SetFind(set,i) ){ + fprintf(out,"%s%s",spacer,lemp->symbols[i]->name); + spacer = " "; + } + } + fprintf(out,"]\n"); +} + +/* Print a plink chain */ +PRIVATE void PlinkPrint(out,plp,tag) +FILE *out; +struct plink *plp; +char *tag; +{ + while( plp ){ + fprintf(out,"%12s%s (state %2d) ","",tag,plp->cfp->stp->index); + ConfigPrint(out,plp->cfp); + fprintf(out,"\n"); + plp = plp->next; + } +} +#endif + +/* Print an action to the given file descriptor. Return FALSE if +** nothing was actually printed. +*/ +int PrintAction(struct action *ap, FILE *fp, int indent){ + int result = 1; + switch( ap->type ){ + case SHIFT: + fprintf(fp,"%*s shift %d",indent,ap->sp->name,ap->x.stp->index); + break; + case REDUCE: + fprintf(fp,"%*s reduce %d",indent,ap->sp->name,ap->x.rp->index); + break; + case ACCEPT: + fprintf(fp,"%*s accept",indent,ap->sp->name); + break; + case ERROR: + fprintf(fp,"%*s error",indent,ap->sp->name); + break; + case CONFLICT: + fprintf(fp,"%*s reduce %-3d ** Parsing conflict **", + indent,ap->sp->name,ap->x.rp->index); + break; + case SH_RESOLVED: + case RD_RESOLVED: + case NOT_USED: + result = 0; + break; + } + return result; +} + +/* Generate the "y.output" log file */ +void ReportOutput(lemp) +struct lemon *lemp; +{ + int i; + struct state *stp; + struct config *cfp; + struct action *ap; + FILE *fp; + + fp = file_open(lemp,".out","w"); + if( fp==0 ) return; + fprintf(fp," \b"); + for(i=0; instate; i++){ + stp = lemp->sorted[i]; + fprintf(fp,"State %d:\n",stp->index); + if( lemp->basisflag ) cfp=stp->bp; + else cfp=stp->cfp; + while( cfp ){ + char buf[20]; + if( cfp->dot==cfp->rp->nrhs ){ + sprintf(buf,"(%d)",cfp->rp->index); + fprintf(fp," %5s ",buf); + }else{ + fprintf(fp," "); + } + ConfigPrint(fp,cfp); + fprintf(fp,"\n"); +#ifdef TEST + SetPrint(fp,cfp->fws,lemp); + PlinkPrint(fp,cfp->fplp,"To "); + PlinkPrint(fp,cfp->bplp,"From"); +#endif + if( lemp->basisflag ) cfp=cfp->bp; + else cfp=cfp->next; + } + fprintf(fp,"\n"); + for(ap=stp->ap; ap; ap=ap->next){ + if( PrintAction(ap,fp,30) ) fprintf(fp,"\n"); + } + fprintf(fp,"\n"); + } + fclose(fp); + return; +} + +/* Search for the file "name" which is in the same directory as +** the exacutable */ +PRIVATE char *pathsearch(argv0,name,modemask) +char *argv0; +char *name; +int modemask; +{ + char *pathlist; + char *path,*cp; + char c; + extern int access(); + +#ifdef __WIN32__ + cp = strrchr(argv0,'\\'); +#else + cp = strrchr(argv0,'/'); +#endif + if( cp ){ + c = *cp; + *cp = 0; + path = (char *)malloc( strlen(argv0) + strlen(name) + 2 ); + if( path ) sprintf(path,"%s/%s",argv0,name); + *cp = c; + }else{ + extern char *getenv(); + pathlist = getenv("PATH"); + if( pathlist==0 ) pathlist = ".:/bin:/usr/bin"; + path = (char *)malloc( strlen(pathlist)+strlen(name)+2 ); + if( path!=0 ){ + while( *pathlist ){ + cp = strchr(pathlist,':'); + if( cp==0 ) cp = &pathlist[strlen(pathlist)]; + c = *cp; + *cp = 0; + sprintf(path,"%s/%s",pathlist,name); + *cp = c; + if( c==0 ) pathlist = ""; + else pathlist = &cp[1]; + if( access(path,modemask)==0 ) break; + } + } + } + return path; +} + +/* Given an action, compute the integer value for that action +** which is to be put in the action table of the generated machine. +** Return negative if no action should be generated. +*/ +PRIVATE int compute_action(lemp,ap) +struct lemon *lemp; +struct action *ap; +{ + int act; + switch( ap->type ){ + case SHIFT: act = ap->x.stp->index; break; + case REDUCE: act = ap->x.rp->index + lemp->nstate; break; + case ERROR: act = lemp->nstate + lemp->nrule; break; + case ACCEPT: act = lemp->nstate + lemp->nrule + 1; break; + default: act = -1; break; + } + return act; +} + +#define LINESIZE 1000 +/* The next cluster of routines are for reading the template file +** and writing the results to the generated parser */ +/* The first function transfers data from "in" to "out" until +** a line is seen which begins with "%%". The line number is +** tracked. +** +** if name!=0, then any word that begin with "Parse" is changed to +** begin with *name instead. +*/ +PRIVATE void tplt_xfer(name,in,out,lineno) +char *name; +FILE *in; +FILE *out; +int *lineno; +{ + int i, iStart; + char line[LINESIZE]; + while( fgets(line,LINESIZE,in) && (line[0]!='%' || line[1]!='%') ){ + (*lineno)++; + iStart = 0; + if( name ){ + for(i=0; line[i]; i++){ + if( line[i]=='P' && strncmp(&line[i],"Parse",5)==0 + && (i==0 || !isalpha(line[i-1])) + ){ + if( i>iStart ) fprintf(out,"%.*s",i-iStart,&line[iStart]); + fprintf(out,"%s",name); + i += 4; + iStart = i+1; + } + } + } + fprintf(out,"%s",&line[iStart]); + } +} + +/* The next function finds the template file and opens it, returning +** a pointer to the opened file. */ +PRIVATE FILE *tplt_open(lemp) +struct lemon *lemp; +{ + static char templatename[] = "lempar.c"; + char buf[1000]; + FILE *in; + char *tpltname; + char *cp; + + if (lemp->templatename) { + tpltname = lemp->templatename; + } + else { + cp = strrchr(lemp->filename,'.'); + if( cp ){ + sprintf(buf,"%.*s.lt",(int)cp-(int)lemp->filename,lemp->filename); + }else{ + sprintf(buf,"%s.lt",lemp->filename); + } + if( access(buf,004)==0 ){ + tpltname = buf; + }else{ + tpltname = pathsearch(lemp->argv0,templatename,0); + } + } + if( tpltname==0 ){ + fprintf(stderr,"Can't find the parser driver template file \"%s\".\n", + templatename); + lemp->errorcnt++; + return 0; + } + in = fopen(tpltname,"r"); + if( in==0 ){ + fprintf(stderr,"Can't open the template file \"%s\".\n",templatename); + lemp->errorcnt++; + return 0; + } + return in; +} + +/* Print a string to the file and keep the linenumber up to date */ +PRIVATE void tplt_print(out,lemp,str,strln,lineno) +FILE *out; +struct lemon *lemp; +char *str; +int strln; +int *lineno; +{ + if( str==0 ) return; + fprintf(out,"#line %d \"%s\"\n",strln,lemp->filename); (*lineno)++; + while( *str ){ + if( *str=='\n' ) (*lineno)++; + putc(*str,out); + str++; + } + fprintf(out,"\n#line %d \"%s\"\n",*lineno+2,lemp->outname); (*lineno)+=2; + return; +} + +/* +** The following routine emits code for the destructor for the +** symbol sp +*/ +void emit_destructor_code(out,sp,lemp,lineno) +FILE *out; +struct symbol *sp; +struct lemon *lemp; +int *lineno; +{ + char *cp; + + int linecnt = 0; + if( sp->type==TERMINAL ){ + cp = lemp->tokendest; + if( cp==0 ) return; + fprintf(out,"#line %d \"%s\"\n{",lemp->tokendestln,lemp->filename); + }else{ + cp = sp->destructor; + if( cp==0 ) return; + fprintf(out,"#line %d \"%s\"\n{",sp->destructorln,lemp->filename); + } + for(; *cp; cp++){ + if( *cp=='$' && cp[1]=='$' ){ + fprintf(out,"(yypminor->yy%d)",sp->dtnum); + cp++; + continue; + } + if( *cp=='\n' ) linecnt++; + fputc(*cp,out); + } + (*lineno) += 3 + linecnt; + fprintf(out,"}\n#line %d \"%s\"\n",*lineno,lemp->outname); + return; +} + +/* +** Return TRUE (non-zero) if the given symbol has a distructor. +*/ +int has_destructor(sp, lemp) +struct symbol *sp; +struct lemon *lemp; +{ + int ret; + if( sp->type==TERMINAL ){ + ret = lemp->tokendest!=0; + }else{ + ret = sp->destructor!=0; + } + return ret; +} + +/* +** Generate code which executes when the rule "rp" is reduced. Write +** the code to "out". Make sure lineno stays up-to-date. +*/ +PRIVATE void emit_code(out,rp,lemp,lineno) +FILE *out; +struct rule *rp; +struct lemon *lemp; +int *lineno; +{ + char *cp, *xp; + int linecnt = 0; + int i; + char lhsused = 0; /* True if the LHS element has been used */ + char used[MAXRHS]; /* True for each RHS element which is used */ + + for(i=0; inrhs; i++) used[i] = 0; + lhsused = 0; + + /* Generate code to do the reduce action */ + if( rp->code ){ + fprintf(out,"#line %d \"%s\"\n{",rp->line,lemp->filename); + for(cp=rp->code; *cp; cp++){ + if( isalpha(*cp) && (cp==rp->code || !isalnum(cp[-1])) ){ + char saved; + for(xp= &cp[1]; isalnum(*xp); xp++); + saved = *xp; + *xp = 0; + if( rp->lhsalias && strcmp(cp,rp->lhsalias)==0 ){ + fprintf(out,"yygotominor.yy%d",rp->lhs->dtnum); + cp = xp; + lhsused = 1; + }else{ + for(i=0; inrhs; i++){ + if( rp->rhsalias[i] && strcmp(cp,rp->rhsalias[i])==0 ){ + fprintf(out,"yymsp[%d].minor.yy%d",i-rp->nrhs+1,rp->rhs[i]->dtnum); + cp = xp; + used[i] = 1; + break; + } + } + } + *xp = saved; + } + if( *cp=='\n' ) linecnt++; + fputc(*cp,out); + } /* End loop */ + (*lineno) += 3 + linecnt; + fprintf(out,"}\n#line %d \"%s\"\n",*lineno,lemp->outname); + } /* End if( rp->code ) */ + + /* Check to make sure the LHS has been used */ + if( rp->lhsalias && !lhsused ){ + ErrorMsg(lemp->filename,rp->ruleline, + "Label \"%s\" for \"%s(%s)\" is never used.", + rp->lhsalias,rp->lhs->name,rp->lhsalias); + lemp->errorcnt++; + } + + /* Generate destructor code for RHS symbols which are not used in the + ** reduce code */ + for(i=0; inrhs; i++){ + if( rp->rhsalias[i] && !used[i] ){ + ErrorMsg(lemp->filename,rp->ruleline, + "Label $%s$ for \"%s(%s)\" is never used.", + rp->rhsalias[i],rp->rhs[i]->name,rp->rhsalias[i]); + lemp->errorcnt++; + }else if( rp->rhsalias[i]==0 ){ + if( has_destructor(rp->rhs[i],lemp) ){ + fprintf(out," yy_destructor(%d,&yymsp[%d].minor);\n", + rp->rhs[i]->index,i-rp->nrhs+1); (*lineno)++; + }else{ + fprintf(out," /* No destructor defined for %s */\n", + rp->rhs[i]->name); + (*lineno)++; + } + } + } + return; +} + +/* +** Print the definition of the union used for the parser's data stack. +** This union contains fields for every possible data type for tokens +** and nonterminals. In the process of computing and printing this +** union, also set the ".dtnum" field of every terminal and nonterminal +** symbol. +*/ +void print_stack_union(out,lemp,plineno,mhflag) +FILE *out; /* The output stream */ +struct lemon *lemp; /* The main info structure for this parser */ +int *plineno; /* Pointer to the line number */ +int mhflag; /* True if generating makeheaders output */ +{ + int lineno = *plineno; /* The line number of the output */ + char **types; /* A hash table of datatypes */ + int arraysize; /* Size of the "types" array */ + int maxdtlength; /* Maximum length of any ".datatype" field. */ + char *stddt; /* Standardized name for a datatype */ + int i,j; /* Loop counters */ + int hash; /* For hashing the name of a type */ + char *name; /* Name of the parser */ + + /* Allocate and initialize types[] and allocate stddt[] */ + arraysize = lemp->nsymbol * 2; + types = (char**)malloc( arraysize * sizeof(char*) ); + for(i=0; insymbol; i++){ + int len; + struct symbol *sp = lemp->symbols[i]; + if( sp->datatype==0 ) continue; + len = strlen(sp->datatype); + if( len>maxdtlength ) maxdtlength = len; + } + stddt = (char*)malloc( maxdtlength*2 + 1 ); + if( types==0 || stddt==0 ){ + fprintf(stderr,"Out of memory.\n"); + exit(1); + } + + /* Build a hash table of datatypes. The ".dtnum" field of each symbol + ** is filled in with the hash index plus 1. A ".dtnum" value of 0 is + ** used for terminal symbols and for nonterminals which don't specify + ** a datatype using the %type directive. */ + for(i=0; insymbol; i++){ + struct symbol *sp = lemp->symbols[i]; + char *cp; + if( sp==lemp->errsym ){ + sp->dtnum = arraysize+1; + continue; + } + if( sp->type!=NONTERMINAL || sp->datatype==0 ){ + sp->dtnum = 0; + continue; + } + cp = sp->datatype; + j = 0; + while( isspace(*cp) ) cp++; + while( *cp ) stddt[j++] = *cp++; + while( j>0 && isspace(stddt[j-1]) ) j--; + stddt[j] = 0; + hash = 0; + for(j=0; stddt[j]; j++){ + hash = hash*53 + stddt[j]; + } + if( hash<0 ) hash = -hash; + hash = hash%arraysize; + while( types[hash] ){ + if( strcmp(types[hash],stddt)==0 ){ + sp->dtnum = hash + 1; + break; + } + hash++; + if( hash>=arraysize ) hash = 0; + } + if( types[hash]==0 ){ + sp->dtnum = hash + 1; + types[hash] = (char*)malloc( strlen(stddt)+1 ); + if( types[hash]==0 ){ + fprintf(stderr,"Out of memory.\n"); + exit(1); + } + strcpy(types[hash],stddt); + } + } + + /* Print out the definition of YYTOKENTYPE and YYMINORTYPE */ + name = lemp->name ? lemp->name : "Parse"; + lineno = *plineno; + if( mhflag ){ fprintf(out,"#if INTERFACE\n"); lineno++; } + fprintf(out,"#define %sTOKENTYPE %s\n",name, + lemp->tokentype?lemp->tokentype:"void*"); lineno++; + if( mhflag ){ fprintf(out,"#endif\n"); lineno++; } + fprintf(out,"typedef union {\n"); lineno++; + fprintf(out," %sTOKENTYPE yy0;\n",name); lineno++; + for(i=0; ierrsym->dtnum); lineno++; + free(stddt); + free(types); + fprintf(out,"} YYMINORTYPE;\n"); lineno++; + *plineno = lineno; +} + +/* Generate C source code for the parser */ +void ReportTable(lemp, mhflag) +struct lemon *lemp; +int mhflag; /* Output in makeheaders format if true */ +{ + FILE *out, *in; + char line[LINESIZE]; + int lineno; + struct state *stp; + struct action *ap; + struct rule *rp; + int i; + int tablecnt; + char *name; + + in = tplt_open(lemp); + if( in==0 ) return; + out = file_open(lemp,".c","w"); + if( out==0 ){ + fclose(in); + return; + } + lineno = 1; + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate the include code, if any */ + tplt_print(out,lemp,lemp->include,lemp->includeln,&lineno); + if( mhflag ){ + char *name = file_makename_using_basename(lemp, ".h"); + fprintf(out,"#include \"%s\"\n", name); lineno++; + free(name); + } + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate #defines for all tokens */ + if( mhflag ){ + char *prefix; + fprintf(out,"#if INTERFACE\n"); lineno++; + if( lemp->tokenprefix ) prefix = lemp->tokenprefix; + else prefix = ""; + for(i=1; interminal; i++){ + fprintf(out,"#define %s%-30s %2d\n",prefix,lemp->symbols[i]->name,i); + lineno++; + } + fprintf(out,"#endif\n"); lineno++; + } + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate the defines */ + fprintf(out,"/* \001 */\n"); + fprintf(out,"#define YYCODETYPE %s\n", + lemp->nsymbol>250?"int":"unsigned char"); lineno++; + fprintf(out,"#define YYNOCODE %d\n",lemp->nsymbol+1); lineno++; + fprintf(out,"#define YYACTIONTYPE %s\n", + lemp->nstate+lemp->nrule>250?"int":"unsigned char"); lineno++; + print_stack_union(out,lemp,&lineno,mhflag); + if( lemp->stacksize ){ + if( atoi(lemp->stacksize)<=0 ){ + ErrorMsg(lemp->filename,0, +"Illegal stack size: [%s]. The stack size should be an integer constant.", + lemp->stacksize); + lemp->errorcnt++; + lemp->stacksize = "100"; + } + fprintf(out,"#define YYSTACKDEPTH %s\n",lemp->stacksize); lineno++; + }else{ + fprintf(out,"#define YYSTACKDEPTH 100\n"); lineno++; + } + if( mhflag ){ + fprintf(out,"#if INTERFACE\n"); lineno++; + } + name = lemp->name ? lemp->name : "Parse"; + if( lemp->arg && lemp->arg[0] ){ + int i; + i = strlen(lemp->arg); + while( i>=1 && isspace(lemp->arg[i-1]) ) i--; + while( i>=1 && isalnum(lemp->arg[i-1]) ) i--; + fprintf(out,"#define %sARGDECL ,%s\n",name,&lemp->arg[i]); lineno++; + fprintf(out,"#define %sXARGDECL %s;\n",name,lemp->arg); lineno++; + fprintf(out,"#define %sANSIARGDECL ,%s\n",name,lemp->arg); lineno++; + }else{ + fprintf(out,"#define %sARGDECL\n",name); lineno++; + fprintf(out,"#define %sXARGDECL\n",name); lineno++; + fprintf(out,"#define %sANSIARGDECL\n",name); lineno++; + } + if( mhflag ){ + fprintf(out,"#endif\n"); lineno++; + } + fprintf(out,"#define YYNSTATE %d\n",lemp->nstate); lineno++; + fprintf(out,"#define YYNRULE %d\n",lemp->nrule); lineno++; + fprintf(out,"#define YYERRORSYMBOL %d\n",lemp->errsym->index); lineno++; + fprintf(out,"#define YYERRSYMDT yy%d\n",lemp->errsym->dtnum); lineno++; + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate the action table. + ** + ** Each entry in the action table is an element of the following + ** structure: + ** struct yyActionEntry { + ** YYCODETYPE lookahead; + ** YYACTIONTYPE action; + ** struct yyActionEntry *next; + ** } + ** + ** The entries are grouped into hash tables, one hash table for each + ** parser state. The hash table has a size which is the smallest + ** power of two needed to hold all entries. + */ + tablecnt = 0; + + /* Loop over parser states */ + for(i=0; instate; i++){ + int tablesize; /* size of the hash table */ + int j,k; /* Loop counter */ + int collide[2048]; /* The collision chain for the table */ + struct action *table[2048]; /* Build the hash table here */ + + /* Find the number of actions and initialize the hash table */ + stp = lemp->sorted[i]; + stp->tabstart = tablecnt; + stp->naction = 0; + for(ap=stp->ap; ap; ap=ap->next){ + if( ap->sp->index!=lemp->nsymbol && compute_action(lemp,ap)>=0 ){ + stp->naction++; + } + } + tablesize = 1; + while( tablesizenaction ) tablesize += tablesize; + assert( tablesize<= sizeof(table)/sizeof(table[0]) ); + for(j=0; jtabdfltact = lemp->nstate + lemp->nrule; + for(ap=stp->ap; ap; ap=ap->next){ + int action = compute_action(lemp,ap); + int h; + if( ap->sp->index==lemp->nsymbol ){ + stp->tabdfltact = action; + }else if( action>=0 ){ + h = ap->sp->index & (tablesize-1); + ap->collide = table[h]; + table[h] = ap; + } + } + + /* Resolve collisions */ + for(j=k=0; jcollide ){ + while( table[k] ) k++; + table[k] = table[j]->collide; + collide[j] = k; + table[j]->collide = 0; + if( kindex); lineno++; + for(j=0; jsp->index, + compute_action(lemp,table[j])); + if( collide[j]>=0 ){ + fprintf(out,"&yyActionTable[%4d] }, /* ", + collide[j] + tablecnt); + }else{ + fprintf(out,"0 }, /* "); + } + PrintAction(table[j],out,22); + fprintf(out," */\n"); + } + lineno++; + } + + /* Update the table count */ + tablecnt += tablesize; + } + tplt_xfer(lemp->name,in,out,&lineno); + lemp->tablesize = tablecnt; + + /* Generate the state table + ** + ** Each entry is an element of the following structure: + ** struct yyStateEntry { + ** struct yyActionEntry *hashtbl; + ** int mask; + ** YYACTIONTYPE actionDefault; + ** } + */ + for(i=0; instate; i++){ + int tablesize; + stp = lemp->sorted[i]; + tablesize = 1; + while( tablesizenaction ) tablesize += tablesize; + fprintf(out," { &yyActionTable[%d], %d, %d},\n", + stp->tabstart, + tablesize - 1, + stp->tabdfltact); lineno++; + } + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate a table containing the symbolic name of every symbol */ + for(i=0; insymbol; i++){ + sprintf(line,"\"%s\",",lemp->symbols[i]->name); + fprintf(out," %-15s",line); + if( (i&3)==3 ){ fprintf(out,"\n"); lineno++; } + } + if( (i&3)!=0 ){ fprintf(out,"\n"); lineno++; } + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate code which executes every time a symbol is popped from + ** the stack while processing errors or while destroying the parser. + ** (In other words, generate the %destructor actions) */ + if( lemp->tokendest ){ + for(i=0; insymbol; i++){ + struct symbol *sp = lemp->symbols[i]; + if( sp==0 || sp->type!=TERMINAL ) continue; + fprintf(out," case %d:\n",sp->index); lineno++; + } + for(i=0; insymbol && lemp->symbols[i]->type!=TERMINAL; i++); + if( insymbol ){ + emit_destructor_code(out,lemp->symbols[i],lemp,&lineno); + fprintf(out," break;\n"); lineno++; + } + } + for(i=0; insymbol; i++){ + struct symbol *sp = lemp->symbols[i]; + if( sp==0 || sp->type==TERMINAL || sp->destructor==0 ) continue; + fprintf(out," case %d:\n",sp->index); lineno++; + emit_destructor_code(out,lemp->symbols[i],lemp,&lineno); + fprintf(out," break;\n"); lineno++; + } + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate code which executes whenever the parser stack overflows */ + tplt_print(out,lemp,lemp->overflow,lemp->overflowln,&lineno); + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate the table of rule information + ** + ** Note: This code depends on the fact that rules are number + ** sequentually beginning with 0. + */ + for(rp=lemp->rule; rp; rp=rp->next){ + fprintf(out," { %d, %d },\n",rp->lhs->index,rp->nrhs); lineno++; + } + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate code which execution during each REDUCE action */ + for(rp=lemp->rule; rp; rp=rp->next){ + fprintf(out," case %d:\n",rp->index); lineno++; + fprintf(out," YYTRACE(\"%s ::=",rp->lhs->name); + for(i=0; inrhs; i++) fprintf(out," %s",rp->rhs[i]->name); + fprintf(out,"\")\n"); lineno++; + emit_code(out,rp,lemp,&lineno); + fprintf(out," break;\n"); lineno++; + } + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate code which executes if a parse fails */ + tplt_print(out,lemp,lemp->failure,lemp->failureln,&lineno); + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate code which executes when a syntax error occurs */ + tplt_print(out,lemp,lemp->error,lemp->errorln,&lineno); + tplt_xfer(lemp->name,in,out,&lineno); + + /* Generate code which executes when the parser accepts its input */ + tplt_print(out,lemp,lemp->accept,lemp->acceptln,&lineno); + tplt_xfer(lemp->name,in,out,&lineno); + + /* Append any addition code the user desires */ + tplt_print(out,lemp,lemp->extracode,lemp->extracodeln,&lineno); + + fclose(in); + fclose(out); + return; +} + +/* Generate a header file for the parser */ +void ReportHeader(lemp) +struct lemon *lemp; +{ + FILE *out, *in; + char *prefix; + char line[LINESIZE]; + char pattern[LINESIZE]; + int i; + + if( lemp->tokenprefix ) prefix = lemp->tokenprefix; + else prefix = ""; + in = file_open(lemp,".h","r"); + if( in ){ + for(i=1; interminal && fgets(line,LINESIZE,in); i++){ + sprintf(pattern,"#define %s%-30s %2d\n",prefix,lemp->symbols[i]->name,i); + if( strcmp(line,pattern) ) break; + } + fclose(in); + if( i==lemp->nterminal ){ + /* No change in the file. Don't rewrite it. */ + return; + } + } + out = file_open(lemp,".h","w"); + if( out ){ + for(i=1; interminal; i++){ + fprintf(out,"#define %s%-30s %2d\n",prefix,lemp->symbols[i]->name,i); + } + fclose(out); + } + return; +} + +/* Reduce the size of the action tables, if possible, by making use +** of defaults. +** +** In this version, if all REDUCE actions use the same rule, make +** them the default. Only default them if there are more than one. +*/ +void CompressTables(lemp) +struct lemon *lemp; +{ + struct state *stp; + struct action *ap; + struct rule *rp; + int i; + int cnt; + + for(i=0; instate; i++){ + stp = lemp->sorted[i]; + + /* Find the first REDUCE action */ + for(ap=stp->ap; ap && ap->type!=REDUCE; ap=ap->next); + if( ap==0 ) continue; + + /* Remember the rule used */ + rp = ap->x.rp; + + /* See if all other REDUCE acitons use the same rule */ + cnt = 1; + for(ap=ap->next; ap; ap=ap->next){ + if( ap->type==REDUCE ){ + if( ap->x.rp!=rp ) break; + cnt++; + } + } + if( ap || cnt==1 ) continue; + + /* Combine all REDUCE actions into a single default */ + for(ap=stp->ap; ap && ap->type!=REDUCE; ap=ap->next); + assert( ap ); + ap->sp = Symbol_new("{default}"); + for(ap=ap->next; ap; ap=ap->next){ + if( ap->type==REDUCE ) ap->type = NOT_USED; + } + stp->ap = Action_sort(stp->ap); + } +} +/***************** From the file "set.c" ************************************/ +/* +** Set manipulation routines for the LEMON parser generator. +*/ + +static int size = 0; + +/* Set the set size */ +void SetSize(n) +int n; +{ + size = n+1; +} + +/* Allocate a new set */ +char *SetNew(){ + char *s; + int i; + s = (char*)malloc( size ); + if( s==0 ){ + extern void memory_error(); + memory_error(); + } + for(i=0; isize = 1024; + x1a->count = 0; + x1a->tbl = (x1node*)malloc( + (sizeof(x1node) + sizeof(x1node*))*1024 ); + if( x1a->tbl==0 ){ + free(x1a); + x1a = 0; + }else{ + int i; + x1a->ht = (x1node**)&(x1a->tbl[1024]); + for(i=0; i<1024; i++) x1a->ht[i] = 0; + } + } +} +/* Insert a new record into the array. Return TRUE if successful. +** Prior data with the same key is NOT overwritten */ +int Strsafe_insert(data) +char *data; +{ + x1node *np; + int h; + int ph; + + if( x1a==0 ) return 0; + ph = strhash(data); + h = ph & (x1a->size-1); + np = x1a->ht[h]; + while( np ){ + if( strcmp(np->data,data)==0 ){ + /* An existing entry with the same key is found. */ + /* Fail because overwrite is not allows. */ + return 0; + } + np = np->next; + } + if( x1a->count>=x1a->size ){ + /* Need to make the hash table bigger */ + int i,size; + struct s_x1 array; + array.size = size = x1a->size*2; + array.count = x1a->count; + array.tbl = (x1node*)malloc( + (sizeof(x1node) + sizeof(x1node*))*size ); + if( array.tbl==0 ) return 0; /* Fail due to malloc failure */ + array.ht = (x1node**)&(array.tbl[size]); + for(i=0; icount; i++){ + x1node *oldnp, *newnp; + oldnp = &(x1a->tbl[i]); + h = strhash(oldnp->data) & (size-1); + newnp = &(array.tbl[i]); + if( array.ht[h] ) array.ht[h]->from = &(newnp->next); + newnp->next = array.ht[h]; + newnp->data = oldnp->data; + newnp->from = &(array.ht[h]); + array.ht[h] = newnp; + } + free(x1a->tbl); + *x1a = array; + } + /* Insert the new data */ + h = ph & (x1a->size-1); + np = &(x1a->tbl[x1a->count++]); + np->data = data; + if( x1a->ht[h] ) x1a->ht[h]->from = &(np->next); + np->next = x1a->ht[h]; + x1a->ht[h] = np; + np->from = &(x1a->ht[h]); + return 1; +} + +/* Return a pointer to data assigned to the given key. Return NULL +** if no such key. */ +char *Strsafe_find(key) +char *key; +{ + int h; + x1node *np; + + if( x1a==0 ) return 0; + h = strhash(key) & (x1a->size-1); + np = x1a->ht[h]; + while( np ){ + if( strcmp(np->data,key)==0 ) break; + np = np->next; + } + return np ? np->data : 0; +} + +/* Return a pointer to the (terminal or nonterminal) symbol "x". +** Create a new symbol if this is the first time "x" has been seen. +*/ +struct symbol *Symbol_new(x) +char *x; +{ + struct symbol *sp; + + sp = Symbol_find(x); + if( sp==0 ){ + sp = (struct symbol *)malloc( sizeof(struct symbol) ); + MemoryCheck(sp); + sp->name = Strsafe(x); + sp->type = isupper(*x) ? TERMINAL : NONTERMINAL; + sp->rule = 0; + sp->prec = -1; + sp->assoc = UNK; + sp->firstset = 0; + sp->lambda = FALSE; + sp->destructor = 0; + sp->datatype = 0; + Symbol_insert(sp,sp->name); + } + return sp; +} + +/* Compare two symbols */ +int Symbolcmpp(a,b) +struct symbol **a; +struct symbol **b; +{ + return strcmp((**a).name,(**b).name); +} + +/* There is one instance of the following structure for each +** associative array of type "x2". +*/ +struct s_x2 { + int size; /* The number of available slots. */ + /* Must be a power of 2 greater than or */ + /* equal to 1 */ + int count; /* Number of currently slots filled */ + struct s_x2node *tbl; /* The data stored here */ + struct s_x2node **ht; /* Hash table for lookups */ +}; + +/* There is one instance of this structure for every data element +** in an associative array of type "x2". +*/ +typedef struct s_x2node { + struct symbol *data; /* The data */ + char *key; /* The key */ + struct s_x2node *next; /* Next entry with the same hash */ + struct s_x2node **from; /* Previous link */ +} x2node; + +/* There is only one instance of the array, which is the following */ +static struct s_x2 *x2a; + +/* Allocate a new associative array */ +void Symbol_init(){ + if( x2a ) return; + x2a = (struct s_x2*)malloc( sizeof(struct s_x2) ); + if( x2a ){ + x2a->size = 128; + x2a->count = 0; + x2a->tbl = (x2node*)malloc( + (sizeof(x2node) + sizeof(x2node*))*128 ); + if( x2a->tbl==0 ){ + free(x2a); + x2a = 0; + }else{ + int i; + x2a->ht = (x2node**)&(x2a->tbl[128]); + for(i=0; i<128; i++) x2a->ht[i] = 0; + } + } +} +/* Insert a new record into the array. Return TRUE if successful. +** Prior data with the same key is NOT overwritten */ +int Symbol_insert(data,key) +struct symbol *data; +char *key; +{ + x2node *np; + int h; + int ph; + + if( x2a==0 ) return 0; + ph = strhash(key); + h = ph & (x2a->size-1); + np = x2a->ht[h]; + while( np ){ + if( strcmp(np->key,key)==0 ){ + /* An existing entry with the same key is found. */ + /* Fail because overwrite is not allows. */ + return 0; + } + np = np->next; + } + if( x2a->count>=x2a->size ){ + /* Need to make the hash table bigger */ + int i,size; + struct s_x2 array; + array.size = size = x2a->size*2; + array.count = x2a->count; + array.tbl = (x2node*)malloc( + (sizeof(x2node) + sizeof(x2node*))*size ); + if( array.tbl==0 ) return 0; /* Fail due to malloc failure */ + array.ht = (x2node**)&(array.tbl[size]); + for(i=0; icount; i++){ + x2node *oldnp, *newnp; + oldnp = &(x2a->tbl[i]); + h = strhash(oldnp->key) & (size-1); + newnp = &(array.tbl[i]); + if( array.ht[h] ) array.ht[h]->from = &(newnp->next); + newnp->next = array.ht[h]; + newnp->key = oldnp->key; + newnp->data = oldnp->data; + newnp->from = &(array.ht[h]); + array.ht[h] = newnp; + } + free(x2a->tbl); + *x2a = array; + } + /* Insert the new data */ + h = ph & (x2a->size-1); + np = &(x2a->tbl[x2a->count++]); + np->key = key; + np->data = data; + if( x2a->ht[h] ) x2a->ht[h]->from = &(np->next); + np->next = x2a->ht[h]; + x2a->ht[h] = np; + np->from = &(x2a->ht[h]); + return 1; +} + +/* Return a pointer to data assigned to the given key. Return NULL +** if no such key. */ +struct symbol *Symbol_find(key) +char *key; +{ + int h; + x2node *np; + + if( x2a==0 ) return 0; + h = strhash(key) & (x2a->size-1); + np = x2a->ht[h]; + while( np ){ + if( strcmp(np->key,key)==0 ) break; + np = np->next; + } + return np ? np->data : 0; +} + +/* Return the n-th data. Return NULL if n is out of range. */ +struct symbol *Symbol_Nth(n) +int n; +{ + struct symbol *data; + if( x2a && n>0 && n<=x2a->count ){ + data = x2a->tbl[n-1].data; + }else{ + data = 0; + } + return data; +} + +/* Return the size of the array */ +int Symbol_count() +{ + return x2a ? x2a->count : 0; +} + +/* Return an array of pointers to all data in the table. +** The array is obtained from malloc. Return NULL if memory allocation +** problems, or if the array is empty. */ +struct symbol **Symbol_arrayof() +{ + struct symbol **array; + int i,size; + if( x2a==0 ) return 0; + size = x2a->count; + array = (struct symbol **)malloc( sizeof(struct symbol *)*size ); + if( array ){ + for(i=0; itbl[i].data; + } + return array; +} + +/* Compare two configurations */ +int Configcmp(a,b) +struct config *a; +struct config *b; +{ + int x; + x = a->rp->index - b->rp->index; + if( x==0 ) x = a->dot - b->dot; + return x; +} + +/* Compare two states */ +PRIVATE int statecmp(a,b) +struct config *a; +struct config *b; +{ + int rc; + for(rc=0; rc==0 && a && b; a=a->bp, b=b->bp){ + rc = a->rp->index - b->rp->index; + if( rc==0 ) rc = a->dot - b->dot; + } + if( rc==0 ){ + if( a ) rc = 1; + if( b ) rc = -1; + } + return rc; +} + +/* Hash a state */ +PRIVATE int statehash(a) +struct config *a; +{ + int h=0; + while( a ){ + h = h*571 + a->rp->index*37 + a->dot; + a = a->bp; + } + return h; +} + +/* Allocate a new state structure */ +struct state *State_new() +{ + struct state *new; + new = (struct state *)malloc( sizeof(struct state) ); + MemoryCheck(new); + return new; +} + +/* There is one instance of the following structure for each +** associative array of type "x3". +*/ +struct s_x3 { + int size; /* The number of available slots. */ + /* Must be a power of 2 greater than or */ + /* equal to 1 */ + int count; /* Number of currently slots filled */ + struct s_x3node *tbl; /* The data stored here */ + struct s_x3node **ht; /* Hash table for lookups */ +}; + +/* There is one instance of this structure for every data element +** in an associative array of type "x3". +*/ +typedef struct s_x3node { + struct state *data; /* The data */ + struct config *key; /* The key */ + struct s_x3node *next; /* Next entry with the same hash */ + struct s_x3node **from; /* Previous link */ +} x3node; + +/* There is only one instance of the array, which is the following */ +static struct s_x3 *x3a; + +/* Allocate a new associative array */ +void State_init(){ + if( x3a ) return; + x3a = (struct s_x3*)malloc( sizeof(struct s_x3) ); + if( x3a ){ + x3a->size = 128; + x3a->count = 0; + x3a->tbl = (x3node*)malloc( + (sizeof(x3node) + sizeof(x3node*))*128 ); + if( x3a->tbl==0 ){ + free(x3a); + x3a = 0; + }else{ + int i; + x3a->ht = (x3node**)&(x3a->tbl[128]); + for(i=0; i<128; i++) x3a->ht[i] = 0; + } + } +} +/* Insert a new record into the array. Return TRUE if successful. +** Prior data with the same key is NOT overwritten */ +int State_insert(data,key) +struct state *data; +struct config *key; +{ + x3node *np; + int h; + int ph; + + if( x3a==0 ) return 0; + ph = statehash(key); + h = ph & (x3a->size-1); + np = x3a->ht[h]; + while( np ){ + if( statecmp(np->key,key)==0 ){ + /* An existing entry with the same key is found. */ + /* Fail because overwrite is not allows. */ + return 0; + } + np = np->next; + } + if( x3a->count>=x3a->size ){ + /* Need to make the hash table bigger */ + int i,size; + struct s_x3 array; + array.size = size = x3a->size*2; + array.count = x3a->count; + array.tbl = (x3node*)malloc( + (sizeof(x3node) + sizeof(x3node*))*size ); + if( array.tbl==0 ) return 0; /* Fail due to malloc failure */ + array.ht = (x3node**)&(array.tbl[size]); + for(i=0; icount; i++){ + x3node *oldnp, *newnp; + oldnp = &(x3a->tbl[i]); + h = statehash(oldnp->key) & (size-1); + newnp = &(array.tbl[i]); + if( array.ht[h] ) array.ht[h]->from = &(newnp->next); + newnp->next = array.ht[h]; + newnp->key = oldnp->key; + newnp->data = oldnp->data; + newnp->from = &(array.ht[h]); + array.ht[h] = newnp; + } + free(x3a->tbl); + *x3a = array; + } + /* Insert the new data */ + h = ph & (x3a->size-1); + np = &(x3a->tbl[x3a->count++]); + np->key = key; + np->data = data; + if( x3a->ht[h] ) x3a->ht[h]->from = &(np->next); + np->next = x3a->ht[h]; + x3a->ht[h] = np; + np->from = &(x3a->ht[h]); + return 1; +} + +/* Return a pointer to data assigned to the given key. Return NULL +** if no such key. */ +struct state *State_find(key) +struct config *key; +{ + int h; + x3node *np; + + if( x3a==0 ) return 0; + h = statehash(key) & (x3a->size-1); + np = x3a->ht[h]; + while( np ){ + if( statecmp(np->key,key)==0 ) break; + np = np->next; + } + return np ? np->data : 0; +} + +/* Return an array of pointers to all data in the table. +** The array is obtained from malloc. Return NULL if memory allocation +** problems, or if the array is empty. */ +struct state **State_arrayof() +{ + struct state **array; + int i,size; + if( x3a==0 ) return 0; + size = x3a->count; + array = (struct state **)malloc( sizeof(struct state *)*size ); + if( array ){ + for(i=0; itbl[i].data; + } + return array; +} + +/* Hash a configuration */ +PRIVATE int confighash(a) +struct config *a; +{ + int h=0; + h = h*571 + a->rp->index*37 + a->dot; + return h; +} + +/* There is one instance of the following structure for each +** associative array of type "x4". +*/ +struct s_x4 { + int size; /* The number of available slots. */ + /* Must be a power of 2 greater than or */ + /* equal to 1 */ + int count; /* Number of currently slots filled */ + struct s_x4node *tbl; /* The data stored here */ + struct s_x4node **ht; /* Hash table for lookups */ +}; + +/* There is one instance of this structure for every data element +** in an associative array of type "x4". +*/ +typedef struct s_x4node { + struct config *data; /* The data */ + struct s_x4node *next; /* Next entry with the same hash */ + struct s_x4node **from; /* Previous link */ +} x4node; + +/* There is only one instance of the array, which is the following */ +static struct s_x4 *x4a; + +/* Allocate a new associative array */ +void Configtable_init(){ + if( x4a ) return; + x4a = (struct s_x4*)malloc( sizeof(struct s_x4) ); + if( x4a ){ + x4a->size = 64; + x4a->count = 0; + x4a->tbl = (x4node*)malloc( + (sizeof(x4node) + sizeof(x4node*))*64 ); + if( x4a->tbl==0 ){ + free(x4a); + x4a = 0; + }else{ + int i; + x4a->ht = (x4node**)&(x4a->tbl[64]); + for(i=0; i<64; i++) x4a->ht[i] = 0; + } + } +} +/* Insert a new record into the array. Return TRUE if successful. +** Prior data with the same key is NOT overwritten */ +int Configtable_insert(data) +struct config *data; +{ + x4node *np; + int h; + int ph; + + if( x4a==0 ) return 0; + ph = confighash(data); + h = ph & (x4a->size-1); + np = x4a->ht[h]; + while( np ){ + if( Configcmp(np->data,data)==0 ){ + /* An existing entry with the same key is found. */ + /* Fail because overwrite is not allows. */ + return 0; + } + np = np->next; + } + if( x4a->count>=x4a->size ){ + /* Need to make the hash table bigger */ + int i,size; + struct s_x4 array; + array.size = size = x4a->size*2; + array.count = x4a->count; + array.tbl = (x4node*)malloc( + (sizeof(x4node) + sizeof(x4node*))*size ); + if( array.tbl==0 ) return 0; /* Fail due to malloc failure */ + array.ht = (x4node**)&(array.tbl[size]); + for(i=0; icount; i++){ + x4node *oldnp, *newnp; + oldnp = &(x4a->tbl[i]); + h = confighash(oldnp->data) & (size-1); + newnp = &(array.tbl[i]); + if( array.ht[h] ) array.ht[h]->from = &(newnp->next); + newnp->next = array.ht[h]; + newnp->data = oldnp->data; + newnp->from = &(array.ht[h]); + array.ht[h] = newnp; + } + free(x4a->tbl); + *x4a = array; + } + /* Insert the new data */ + h = ph & (x4a->size-1); + np = &(x4a->tbl[x4a->count++]); + np->data = data; + if( x4a->ht[h] ) x4a->ht[h]->from = &(np->next); + np->next = x4a->ht[h]; + x4a->ht[h] = np; + np->from = &(x4a->ht[h]); + return 1; +} + +/* Return a pointer to data assigned to the given key. Return NULL +** if no such key. */ +struct config *Configtable_find(key) +struct config *key; +{ + int h; + x4node *np; + + if( x4a==0 ) return 0; + h = confighash(key) & (x4a->size-1); + np = x4a->ht[h]; + while( np ){ + if( Configcmp(np->data,key)==0 ) break; + np = np->next; + } + return np ? np->data : 0; +} + +/* Remove all data from the table. Pass each data to the function "f" +** as it is removed. ("f" may be null to avoid this step.) */ +void Configtable_clear(f) +int(*f)(/* struct config * */); +{ + int i; + if( x4a==0 || x4a->count==0 ) return; + if( f ) for(i=0; icount; i++) (*f)(x4a->tbl[i].data); + for(i=0; isize; i++) x4a->ht[i] = 0; + x4a->count = 0; + return; +} diff --git a/tools/lemon/lemon.html b/tools/lemon/lemon.html new file mode 100644 index 00000000..9b4648f4 --- /dev/null +++ b/tools/lemon/lemon.html @@ -0,0 +1,861 @@ + + +The Lemon Parser Generator + + +

The Lemon Parser Generator

+ +

Lemon is an LALR(1) parser generator for C or C++. +It does the same job as ``bison'' and ``yacc''. +But lemon is not another bison or yacc clone. It +uses a different grammar syntax which is designed to +reduce the number of coding errors. Lemon also uses a more +sophisticated parsing engine that is faster than yacc and +bison and which is both reentrant and thread-safe. +Furthermore, Lemon implements features that can be used +to eliminate resource leaks, making is suitable for use +in long-running programs such as graphical user interfaces +or embedded controllers.

+ +

This document is an introduction to the Lemon +parser generator.

+ +

Theory of Operation

+ +

The main goal of Lemon is to translate a context free grammar (CFG) +for a particular language into C code that implements a parser for +that language. +The program has two inputs: +

    +
  • The grammar specification. +
  • A parser template file. +
+Typically, only the grammar specification is supplied by the programmer. +Lemon comes with a default parser template which works fine for most +applications. But the user is free to substitute a different parser +template if desired.

+ +

Depending on command-line options, Lemon will generate between +one and three files of outputs. +

    +
  • C code to implement the parser. +
  • A header file defining an integer ID for each terminal symbol. +
  • An information file that describes the states of the generated parser + automaton. +
+By default, all three of these output files are generated. +The header file is suppressed if the ``-m'' command-line option is +used and the report file is omitted when ``-q'' is selected.

+ +

The grammar specification file uses a ``.y'' suffix, by convention. +In the examples used in this document, we'll assume the name of the +grammar file is ``gram.y''. A typical use of Lemon would be the +following command: +

+   lemon gram.y
+
+This command will generate three output files named ``gram.c'', +``gram.h'' and ``gram.out''. +The first is C code to implement the parser. The second +is the header file that defines numerical values for all +terminal symbols, and the last is the report that explains +the states used by the parser automaton.

+ +

Command Line Options

+ +

The behavior of Lemon can be modified using command-line options. +You can obtain a list of the available command-line options together +with a brief explanation of what each does by typing +

+   lemon -?
+
+As of this writing, the following command-line options are supported: +
    +
  • -b +
  • -c +
  • -g +
  • -m +
  • -q +
  • -s +
  • -x +
+The ``-b'' option reduces the amount of text in the report file by +printing only the basis of each parser state, rather than the full +configuration. +The ``-c'' option suppresses action table compression. Using -c +will make the parser a little larger and slower but it will detect +syntax errors sooner. +The ``-g'' option causes no output files to be generated at all. +Instead, the input grammar file is printed on standard output but +with all comments, actions and other extraneous text deleted. This +is a useful way to get a quick summary of a grammar. +The ``-m'' option causes the output C source file to be compatible +with the ``makeheaders'' program. +Makeheaders is a program that automatically generates header files +from C source code. When the ``-m'' option is used, the header +file is not output since the makeheaders program will take care +of generated all header files automatically. +The ``-q'' option suppresses the report file. +Using ``-s'' causes a brief summary of parser statistics to be +printed. Like this: +
+   Parser statistics: 74 terminals, 70 nonterminals, 179 rules
+                      340 states, 2026 parser table entries, 0 conflicts
+
+Finally, the ``-x'' option causes Lemon to print its version number +and copyright information +and then stop without attempting to read the grammar or generate a parser.

+ +

The Parser Interface

+ +

Lemon doesn't generate a complete, working program. It only generates +a few subroutines that implement a parser. This section describes +the interface to those subroutines. It is up to the programmer to +call these subroutines in an appropriate way in order to produce a +complete system.

+ +

Before a program begins using a Lemon-generated parser, the program +must first create the parser. +A new parser is created as follows: +

+   void *pParser = ParseAlloc( malloc );
+
+The ParseAlloc() routine allocates and initializes a new parser and +returns a pointer to it. +The actual data structure used to represent a parser is opaque -- +its internal structure is not visible or usable by the calling routine. +For this reason, the ParseAlloc() routine returns a pointer to void +rather than a pointer to some particular structure. +The sole argument to the ParseAlloc() routine is a pointer to the +subroutine used to allocate memory. Typically this means ``malloc()''.

+ +

After a program is finished using a parser, it can reclaim all +memory allocated by that parser by calling +

+   ParseFree(pParser, free);
+
+The first argument is the same pointer returned by ParseAlloc(). The +second argument is a pointer to the function used to release bulk +memory back to the system.

+ +

After a parser has been allocated using ParseAlloc(), the programmer +must supply the parser with a sequence of tokens (terminal symbols) to +be parsed. This is accomplished by calling the following function +once for each token: +

+   Parse(pParser, hTokenID, sTokenData, pArg);
+
+The first argument to the Parse() routine is the pointer returned by +ParseAlloc(). +The second argument is a small positive integer that tells the parse the +type of the next token in the data stream. +There is one token type for each terminal symbol in the grammar. +The gram.h file generated by Lemon contains #define statements that +map symbolic terminal symbol names into appropriate integer values. +(A value of 0 for the second argument is a special flag to the +parser to indicate that the end of input has been reached.) +The third argument is the value of the given token. By default, +the type of the third argument is integer, but the grammar will +usually redefine this type to be some kind of structure. +Typically the second argument will be a broad category of tokens +such as ``identifier'' or ``number'' and the third argument will +be the name of the identifier or the value of the number.

+ +

The Parse() function may have either three or four arguments, +depending on the grammar. If the grammar specification file request +it, the Parse() function will have a fourth parameter that can be +of any type chosen by the programmer. The parser doesn't do anything +with this argument except to pass it through to action routines. +This is a convenient mechanism for passing state information down +to the action routines without having to use global variables.

+ +

A typical use of a Lemon parser might look something like the +following: +

+   01 ParseTree *ParseFile(const char *zFilename){
+   02    Tokenizer *pTokenizer;
+   03    void *pParser;
+   04    Token sToken;
+   05    int hTokenId;
+   06    ParserState sState;
+   07
+   08    pTokenizer = TokenizerCreate(zFilename);
+   09    pParser = ParseAlloc( malloc );
+   10    InitParserState(&sState);
+   11    while( GetNextToken(pTokenizer, &hTokenId, &sToken) ){
+   12       Parse(pParser, hTokenId, sToken, &sState);
+   13    }
+   14    Parse(pParser, 0, sToken, &sState);
+   15    ParseFree(pParser, free );
+   16    TokenizerFree(pTokenizer);
+   17    return sState.treeRoot;
+   18 }
+
+This example shows a user-written routine that parses a file of +text and returns a pointer to the parse tree. +(We've omitted all error-handling from this example to keep it +simple.) +We assume the existence of some kind of tokenizer which is created +using TokenizerCreate() on line 8 and deleted by TokenizerFree() +on line 16. The GetNextToken() function on line 11 retrieves the +next token from the input file and puts its type in the +integer variable hTokenId. The sToken variable is assumed to be +some kind of structure that contains details about each token, +such as its complete text, what line it occurs on, etc.

+ +

This example also assumes the existence of structure of type +ParserState that holds state information about a particular parse. +An instance of such a structure is created on line 6 and initialized +on line 10. A pointer to this structure is passed into the Parse() +routine as the optional 4th argument. +The action routine specified by the grammar for the parser can use +the ParserState structure to hold whatever information is useful and +appropriate. In the example, we note that the treeRoot field of +the ParserState structure is left pointing to the root of the parse +tree.

+ +

The core of this example as it relates to Lemon is as follows: +

+   ParseFile(){
+      pParser = ParseAlloc( malloc );
+      while( GetNextToken(pTokenizer,&hTokenId, &sToken) ){
+         Parse(pParser, hTokenId, sToken);
+      }
+      Parse(pParser, 0, sToken);
+      ParseFree(pParser, free );
+   }
+
+Basically, what a program has to do to use a Lemon-generated parser +is first create the parser, then send it lots of tokens obtained by +tokenizing an input source. When the end of input is reached, the +Parse() routine should be called one last time with a token type +of 0. This step is necessary to inform the parser that the end of +input has been reached. Finally, we reclaim memory used by the +parser by calling ParseFree().

+ +

There is one other interface routine that should be mentioned +before we move on. +The ParseTrace() function can be used to generate debugging output +from the parser. A prototype for this routine is as follows: +

+   ParseTrace(FILE *stream, char *zPrefix);
+
+After this routine is called, a short (one-line) message is written +to the designated output stream every time the parser changes states +or calls an action routine. Each such message is prefaced using +the text given by zPrefix. This debugging output can be turned off +by calling ParseTrace() again with a first argument of NULL (0).

+ +

Differences With YACC and BISON

+ +

Programmers who have previously used the yacc or bison parser +generator will notice several important differences between yacc and/or +bison and Lemon. +

    +
  • In yacc and bison, the parser calls the tokenizer. In Lemon, + the tokenizer calls the parser. +
  • Lemon uses no global variables. Yacc and bison use global variables + to pass information between the tokenizer and parser. +
  • Lemon allows multiple parsers to be running simultaneously. Yacc + and bison do not. +
+These differences may cause some initial confusion for programmers +with prior yacc and bison experience. +But after years of experience using Lemon, I firmly +believe that the Lemon way of doing things is better.

+ +

Input File Syntax

+ +

The main purpose of the grammar specification file for Lemon is +to define the grammar for the parser. But the input file also +specifies additional information Lemon requires to do its job. +Most of the work in using Lemon is in writing an appropriate +grammar file.

+ +

The grammar file for lemon is, for the most part, free format. +It does not have sections or divisions like yacc or bison. Any +declaration can occur at any point in the file. +Lemon ignores whitespace (except where it is needed to separate +tokens) and it honors the same commenting conventions as C and C++.

+ +

Terminals and Nonterminals

+ +

A terminal symbol (token) is any string of alphanumeric +and underscore characters +that begins with an upper case letter. +A terminal can contain lower class letters after the first character, +but the usual convention is to make terminals all upper case. +A nonterminal, on the other hand, is any string of alphanumeric +and underscore characters than begins with a lower case letter. +Again, the usual convention is to make nonterminals use all lower +case letters.

+ +

In Lemon, terminal and nonterminal symbols do not need to +be declared or identified in a separate section of the grammar file. +Lemon is able to generate a list of all terminals and nonterminals +by examining the grammar rules, and it can always distinguish a +terminal from a nonterminal by checking the case of the first +character of the name.

+ +

Yacc and bison allow terminal symbols to have either alphanumeric +names or to be individual characters included in single quotes, like +this: ')' or '$'. Lemon does not allow this alternative form for +terminal symbols. With Lemon, all symbols, terminals and nonterminals, +must have alphanumeric names.

+ +

Grammar Rules

+ +

The main component of a Lemon grammar file is a sequence of grammar +rules. +Each grammar rule consists of a nonterminal symbol followed by +the special symbol ``::='' and then a list of terminals and/or nonterminals. +The rule is terminated by a period. +The list of terminals and nonterminals on the right-hand side of the +rule can be empty. +Rules can occur in any order, except that the left-hand side of the +first rule is assumed to be the start symbol for the grammar (unless +specified otherwise using the %start directive described below.) +A typical sequence of grammar rules might look something like this: +

+  expr ::= expr PLUS expr.
+  expr ::= expr TIMES expr.
+  expr ::= LPAREN expr RPAREN.
+  expr ::= VALUE.
+
+

+ +

There is one non-terminal in this example, ``expr'', and five +terminal symbols or tokens: ``PLUS'', ``TIMES'', ``LPAREN'', +``RPAREN'' and ``VALUE''.

+ +

Like yacc and bison, Lemon allows the grammar to specify a block +of C code that will be executed whenever a grammar rule is reduced +by the parser. +In Lemon, this action is specified by putting the C code (contained +within curly braces {...}) immediately after the +period that closes the rule. +For example: +

+  expr ::= expr PLUS expr.   { printf("Doing an addition...\n"); }
+
+

+ +

In order to be useful, grammar actions must normally be linked to +their associated grammar rules. +In yacc and bison, this is accomplished by embedding a ``$$'' in the +action to stand for the value of the left-hand side of the rule and +symbols ``$1'', ``$2'', and so forth to stand for the value of +the terminal or nonterminal at position 1, 2 and so forth on the +right-hand side of the rule. +This idea is very powerful, but it is also very error-prone. The +single most common source of errors in a yacc or bison grammar is +to miscount the number of symbols on the right-hand side of a grammar +rule and say ``$7'' when you really mean ``$8''.

+ +

Lemon avoids the need to count grammar symbols by assigning symbolic +names to each symbol in a grammar rule and then using those symbolic +names in the action. +In yacc or bison, one would write this: +

+  expr -> expr PLUS expr  { $$ = $1 + $3; };
+
+But in Lemon, the same rule becomes the following: +
+  expr(A) ::= expr(B) PLUS expr(C).  { A = B+C; }
+
+In the Lemon rule, any symbol in parentheses after a grammar rule +symbol becomes a place holder for that symbol in the grammar rule. +This place holder can then be used in the associated C action to +stand for the value of that symbol.

+ +

The Lemon notation for linking a grammar rule with its reduce +action is superior to yacc/bison on several counts. +First, as mentioned above, the Lemon method avoids the need to +count grammar symbols. +Secondly, if a terminal or nonterminal in a Lemon grammar rule +includes a linking symbol in parentheses but that linking symbol +is not actually used in the reduce action, then an error message +is generated. +For example, the rule +

+  expr(A) ::= expr(B) PLUS expr(C).  { A = B; }
+
+will generate an error because the linking symbol ``C'' is used +in the grammar rule but not in the reduce action.

+ +

The Lemon notation for linking grammar rules to reduce actions +also facilitates the use of destructors for reclaiming memory +allocated by the values of terminals and nonterminals on the +right-hand side of a rule.

+ +

Precedence Rules

+ +

Lemon resolves parsing ambiguities in exactly the same way as +yacc and bison. A shift-reduce conflict is resolved in favor +of the shift, and a reduce-reduce conflict is resolved by reducing +whichever rule comes first in the grammar file.

+ +

Just like in +yacc and bison, Lemon allows a measure of control +over the resolution of paring conflicts using precedence rules. +A precedence value can be assigned to any terminal symbol +using the %left, %right or %nonassoc directives. Terminal symbols +mentioned in earlier directives have a lower precedence that +terminal symbols mentioned in later directives. For example:

+ +

+   %left AND.
+   %left OR.
+   %nonassoc EQ NE GT GE LT LE.
+   %left PLUS MINUS.
+   %left TIMES DIVIDE MOD.
+   %right EXP NOT.
+

+ +

In the preceding sequence of directives, the AND operator is +defined to have the lowest precedence. The OR operator is one +precedence level higher. And so forth. Hence, the grammar would +attempt to group the ambiguous expression +

+     a AND b OR c
+
+like this +
+     a AND (b OR c).
+
+The associativity (left, right or nonassoc) is used to determine +the grouping when the precedence is the same. AND is left-associative +in our example, so +
+     a AND b AND c
+
+is parsed like this +
+     (a AND b) AND c.
+
+The EXP operator is right-associative, though, so +
+     a EXP b EXP c
+
+is parsed like this +
+     a EXP (b EXP c).
+
+The nonassoc precedence is used for non-associative operators. +So +
+     a EQ b EQ c
+
+is an error.

+ +

The precedence of non-terminals is transferred to rules as follows: +The precedence of a grammar rule is equal to the precedence of the +left-most terminal symbol in the rule for which a precedence is +defined. This is normally what you want, but in those cases where +you want to precedence of a grammar rule to be something different, +you can specify an alternative precedence symbol by putting the +symbol in square braces after the period at the end of the rule and +before any C-code. For example:

+ +

+   expr = MINUS expr.  [NOT]
+

+ +

This rule has a precedence equal to that of the NOT symbol, not the +MINUS symbol as would have been the case by default.

+ +

With the knowledge of how precedence is assigned to terminal +symbols and individual +grammar rules, we can now explain precisely how parsing conflicts +are resolved in Lemon. Shift-reduce conflicts are resolved +as follows: +

    +
  • If either the token to be shifted or the rule to be reduced + lacks precedence information, then resolve in favor of the + shift, but report a parsing conflict. +
  • If the precedence of the token to be shifted is greater than + the precedence of the rule to reduce, then resolve in favor + of the shift. No parsing conflict is reported. +
  • If the precedence of the token it be shifted is less than the + precedence of the rule to reduce, then resolve in favor of the + reduce action. No parsing conflict is reported. +
  • If the precedences are the same and the shift token is + right-associative, then resolve in favor of the shift. + No parsing conflict is reported. +
  • If the precedences are the same the the shift token is + left-associative, then resolve in favor of the reduce. + No parsing conflict is reported. +
  • Otherwise, resolve the conflict by doing the shift and + report the parsing conflict. +
+Reduce-reduce conflicts are resolved this way: +
    +
  • If either reduce rule + lacks precedence information, then resolve in favor of the + rule that appears first in the grammar and report a parsing + conflict. +
  • If both rules have precedence and the precedence is different + then resolve the dispute in favor of the rule with the highest + precedence and do not report a conflict. +
  • Otherwise, resolve the conflict by reducing by the rule that + appears first in the grammar and report a parsing conflict. +
+ +

Special Directives

+ +

The input grammar to Lemon consists of grammar rules and special +directives. We've described all the grammar rules, so now we'll +talk about the special directives.

+ +

Directives in lemon can occur in any order. You can put them before +the grammar rules, or after the grammar rules, or in the mist of the +grammar rules. It doesn't matter. The relative order of +directives used to assign precedence to terminals is important, but +other than that, the order of directives in Lemon is arbitrary.

+ +

Lemon supports the following special directives: +

    +
  • %destructor +
  • %extra_argument +
  • %include +
  • %left +
  • %name +
  • %nonassoc +
  • %parse_accept +
  • %parse_failure +
  • %right +
  • %stack_overflow +
  • %stack_size +
  • %start_symbol +
  • %syntax_error +
  • %token_destructor +
  • %token_prefix +
  • %token_type +
  • %type +
+Each of these directives will be described separately in the +following sections:

+ +

The %destructor directive

+ +

The %destructor directive is used to specify a destructor for +a non-terminal symbol. +(See also the %token_destructor directive which is used to +specify a destructor for terminal symbols.)

+ +

A non-terminal's destructor is called to dispose of the +non-terminal's value whenever the non-terminal is popped from +the stack. This includes all of the following circumstances: +

    +
  • When a rule reduces and the value of a non-terminal on + the right-hand side is not linked to C code. +
  • When the stack is popped during error processing. +
  • When the ParseFree() function runs. +
+The destructor can do whatever it wants with the value of +the non-terminal, but its design is to deallocate memory +or other resources held by that non-terminal.

+ +

Consider an example: +

+   %type nt {void*}
+   %destructor nt { free($$); }
+   nt(A) ::= ID NUM.   { A = malloc( 100 ); }
+
+This example is a bit contrived but it serves to illustrate how +destructors work. The example shows a non-terminal named +``nt'' that holds values of type ``void*''. When the rule for +an ``nt'' reduces, it sets the value of the non-terminal to +space obtained from malloc(). Later, when the nt non-terminal +is popped from the stack, the destructor will fire and call +free() on this malloced space, thus avoiding a memory leak. +(Note that the symbol ``$$'' in the destructor code is replaced +by the value of the non-terminal.)

+ +

It is important to note that the value of a non-terminal is passed +to the destructor whenever the non-terminal is removed from the +stack, unless the non-terminal is used in a C-code action. If +the non-terminal is used by C-code, then it is assumed that the +C-code will take care of destroying it if it should really +be destroyed. More commonly, the value is used to build some +larger structure and we don't want to destroy it, which is why +the destructor is not called in this circumstance.

+ +

By appropriate use of destructors, it is possible to +build a parser using Lemon that can be used within a long-running +program, such as a GUI, that will not leak memory or other resources. +To do the same using yacc or bison is much more difficult.

+ +

The %extra_argument directive

+ +The %extra_argument directive instructs Lemon to add a 4th parameter +to the parameter list of the Parse() function it generates. Lemon +doesn't do anything itself with this extra argument, but it does +make the argument available to C-code action routines, destructors, +and so forth. For example, if the grammar file contains:

+ +

+    %extra_argument { MyStruct *pAbc }
+

+ +

Then the Parse() function generated will have an 4th parameter +of type ``MyStruct*'' and all action routines will have access to +a variable named ``pAbc'' that is the value of the 4th parameter +in the most recent call to Parse().

+ +

The %include directive

+ +

The %include directive specifies C code that is included at the +top of the generated parser. You can include any text you want -- +the Lemon parser generator copies to blindly. If you have multiple +%include directives in your grammar file, their values are concatenated +before being put at the beginning of the generated parser.

+ +

The %include directive is very handy for getting some extra #include +preprocessor statements at the beginning of the generated parser. +For example:

+ +

+   %include {#include <unistd.h>}
+

+ +

This might be needed, for example, if some of the C actions in the +grammar call functions that are prototyed in unistd.h.

+ +

The %left directive

+ +The %left directive is used (along with the %right and +%nonassoc directives) to declare precedences of terminal +symbols. Every terminal symbol whose name appears after +a %left directive but before the next period (``.'') is +given the same left-associative precedence value. Subsequent +%left directives have higher precedence. For example:

+ +

+   %left AND.
+   %left OR.
+   %nonassoc EQ NE GT GE LT LE.
+   %left PLUS MINUS.
+   %left TIMES DIVIDE MOD.
+   %right EXP NOT.
+

+ +

Note the period that terminates each %left, %right or %nonassoc +directive.

+ +

LALR(1) grammars can get into a situation where they require +a large amount of stack space if you make heavy use or right-associative +operators. For this reason, it is recommended that you use %left +rather than %right whenever possible.

+ +

The %name directive

+ +

By default, the functions generated by Lemon all begin with the +five-character string ``Parse''. You can change this string to something +different using the %name directive. For instance:

+ +

+   %name Abcde
+

+ +

Putting this directive in the grammar file will cause Lemon to generate +functions named +

    +
  • AbcdeAlloc(), +
  • AbcdeFree(), +
  • AbcdeTrace(), and +
  • Abcde(). +
+The %name directive allows you to generator two or more different +parsers and link them all into the same executable. +

+ +

The %nonassoc directive

+ +

This directive is used to assign non-associative precedence to +one or more terminal symbols. See the section on precedence rules +or on the %left directive for additional information.

+ +

The %parse_accept directive

+ +

The %parse_accept directive specifies a block of C code that is +executed whenever the parser accepts its input string. To ``accept'' +an input string means that the parser was able to process all tokens +without error.

+ +

For example:

+ +

+   %parse_accept {
+      printf("parsing complete!\n");
+   }
+

+ + +

The %parse_failure directive

+ +

The %parse_failure directive specifies a block of C code that +is executed whenever the parser fails complete. This code is not +executed until the parser has tried and failed to resolve an input +error using is usual error recovery strategy. The routine is +only invoked when parsing is unable to continue.

+ +

+   %parse_failure {
+     fprintf(stderr,"Giving up.  Parser is hopelessly lost...\n");
+   }
+

+ +

The %right directive

+ +

This directive is used to assign right-associative precedence to +one or more terminal symbols. See the section on precedence rules +or on the %left directive for additional information.

+ +

The %stack_overflow directive

+ +

The %stack_overflow directive specifies a block of C code that +is executed if the parser's internal stack ever overflows. Typically +this just prints an error message. After a stack overflow, the parser +will be unable to continue and must be reset.

+ +

+   %stack_overflow {
+     fprintf(stderr,"Giving up.  Parser stack overflow\n");
+   }
+

+ +

You can help prevent parser stack overflows by avoiding the use +of right recursion and right-precedence operators in your grammar. +Use left recursion and and left-precedence operators instead, to +encourage rules to reduce sooner and keep the stack size down. +For example, do rules like this: +

+   list ::= list element.      // left-recursion.  Good!
+   list ::= .
+
+Not like this: +
+   list ::= element list.      // right-recursion.  Bad!
+   list ::= .
+
+ +

The %stack_size directive

+ +

If stack overflow is a problem and you can't resolve the trouble +by using left-recursion, then you might want to increase the size +of the parser's stack using this directive. Put an positive integer +after the %stack_size directive and Lemon will generate a parse +with a stack of the requested size. The default value is 100.

+ +

+   %stack_size 2000
+

+ +

The %start_symbol directive

+ +

By default, the start-symbol for the grammar that Lemon generates +is the first non-terminal that appears in the grammar file. But you +can choose a different start-symbol using the %start_symbol directive.

+ +

+   %start_symbol  prog
+

+ +

The %token_destructor directive

+ +

The %destructor directive assigns a destructor to a non-terminal +symbol. (See the description of the %destructor directive above.) +This directive does the same thing for all terminal symbols.

+ +

Unlike non-terminal symbols which may each have a different data type +for their values, terminals all use the same data type (defined by +the %token_type directive) and so they use a common destructor. Other +than that, the token destructor works just like the non-terminal +destructors.

+ +

The %token_prefix directive

+ +

Lemon generates #defines that assign small integer constants +to each terminal symbol in the grammar. If desired, Lemon will +add a prefix specified by this directive +to each of the #defines it generates. +So if the default output of Lemon looked like this: +

+    #define AND              1
+    #define MINUS            2
+    #define OR               3
+    #define PLUS             4
+
+You can insert a statement into the grammar like this: +
+    %token_prefix    TOKEN_
+
+to cause Lemon to produce these symbols instead: +
+    #define TOKEN_AND        1
+    #define TOKEN_MINUS      2
+    #define TOKEN_OR         3
+    #define TOKEN_PLUS       4
+
+ +

The %token_type and %type directives

+ +

These directives are used to specify the data types for values +on the parser's stack associated with terminal and non-terminal +symbols. The values of all terminal symbols must be of the same +type. This turns out to be the same data type as the 3rd parameter +to the Parse() function generated by Lemon. Typically, you will +make the value of a terminal symbol by a pointer to some kind of +token structure. Like this:

+ +

+   %token_type    {Token*}
+

+ +

If the data type of terminals is not specified, the default value +is ``int''.

+ +

Non-terminal symbols can each have their own data types. Typically +the data type of a non-terminal is a pointer to the root of a parse-tree +structure that contains all information about that non-terminal. +For example:

+ +

+   %type   expr  {Expr*}
+

+ +

Each entry on the parser's stack is actually a union containing +instances of all data types for every non-terminal and terminal symbol. +Lemon will automatically use the correct element of this union depending +on what the corresponding non-terminal or terminal symbol is. But +the grammar designer should keep in mind that the size of the union +will be the size of its largest element. So if you have a single +non-terminal whose data type requires 1K of storage, then your 100 +entry parser stack will require 100K of heap space. If you are willing +and able to pay that price, fine. You just need to know.

+ +

Error Processing

+ +

After extensive experimentation over several years, it has been +discovered that the error recovery strategy used by yacc is about +as good as it gets. And so that is what Lemon uses.

+ +

When a Lemon-generated parser encounters a syntax error, it +first invokes the code specified by the %syntax_error directive, if +any. It then enters its error recovery strategy. The error recovery +strategy is to begin popping the parsers stack until it enters a +state where it is permitted to shift a special non-terminal symbol +named ``error''. It then shifts this non-terminal and continues +parsing. But the %syntax_error routine will not be called again +until at least three new tokens have been successfully shifted.

+ +

If the parser pops its stack until the stack is empty, and it still +is unable to shift the error symbol, then the %parse_failed routine +is invoked and the parser resets itself to its start state, ready +to begin parsing a new file. This is what will happen at the very +first syntax error, of course, if there are no instances of the +``error'' non-terminal in your grammar.

+ + + diff --git a/tools/lemon/lempar.c b/tools/lemon/lempar.c new file mode 100644 index 00000000..73783a3d --- /dev/null +++ b/tools/lemon/lempar.c @@ -0,0 +1,598 @@ +/* Driver template for the LEMON parser generator. +** Copyright 1991-1995 by D. Richard Hipp. +** +** This library is free software; you can redistribute it and/or +** modify it under the terms of the GNU Library General Public +** License as published by the Free Software Foundation; either +** version 2 of the License, or (at your option) any later version. +** +** This library is distributed in the hope that it will be useful, +** but WITHOUT ANY WARRANTY; without even the implied warranty of +** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +** Library General Public License for more details. +** +** You should have received a copy of the GNU Library General Public +** License along with this library; if not, write to the +** Free Software Foundation, Inc., 59 Temple Place - Suite 330, +** Boston, MA 02111-1307, USA. +** +** Modified 1997 to make it suitable for use with makeheaders. +*/ +/* First off, code is include which follows the "include" declaration +** in the input file. */ +#include +%% +/* Next is all token values, in a form suitable for use by makeheaders. +** This section will be null unless lemon is run with the -m switch. +*/ +/* +** These constants (all generated automatically by the parser generator) +** specify the various kinds of tokens (terminals) that the parser +** understands. +** +** Each symbol here is a terminal symbol in the grammar. +*/ +%% +/* Make sure the INTERFACE macro is defined. +*/ +#ifndef INTERFACE +# define INTERFACE 1 +#endif +/* The next thing included is series of defines which control +** various aspects of the generated parser. +** YYCODETYPE is the data type used for storing terminal +** and nonterminal numbers. "unsigned char" is +** used if there are fewer than 250 terminals +** and nonterminals. "int" is used otherwise. +** YYNOCODE is a number of type YYCODETYPE which corresponds +** to no legal terminal or nonterminal number. This +** number is used to fill in empty slots of the hash +** table. +** YYACTIONTYPE is the data type used for storing terminal +** and nonterminal numbers. "unsigned char" is +** used if there are fewer than 250 rules and +** states combined. "int" is used otherwise. +** ParseTOKENTYPE is the data type used for minor tokens given +** directly to the parser from the tokenizer. +** YYMINORTYPE is the data type used for all minor tokens. +** This is typically a union of many types, one of +** which is ParseTOKENTYPE. The entry in the union +** for base tokens is called "yy0". +** YYSTACKDEPTH is the maximum depth of the parser's stack. +** ParseARGDECL is a declaration of a 3rd argument to the +** parser, or null if there is no extra argument. +** ParseKRARGDECL A version of ParseARGDECL for K&R C. +** ParseANSIARGDECL A version of ParseARGDECL for ANSI C. +** YYNSTATE the combined number of states. +** YYNRULE the number of rules in the grammar +** YYERRORSYMBOL is the code number of the error symbol. If not +** defined, then do no error processing. +*/ +%% +#define YY_NO_ACTION (YYNSTATE+YYNRULE+2) +#define YY_ACCEPT_ACTION (YYNSTATE+YYNRULE+1) +#define YY_ERROR_ACTION (YYNSTATE+YYNRULE) +/* Next is the action table. Each entry in this table contains +** +** + An integer which is the number representing the look-ahead +** token +** +** + An integer indicating what action to take. Number (N) between +** 0 and YYNSTATE-1 mean shift the look-ahead and go to state N. +** Numbers between YYNSTATE and YYNSTATE+YYNRULE-1 mean reduce by +** rule N-YYNSTATE. Number YYNSTATE+YYNRULE means that a syntax +** error has occurred. Number YYNSTATE+YYNRULE+1 means the parser +** accepts its input. +** +** + A pointer to the next entry with the same hash value. +** +** The action table is really a series of hash tables. Each hash +** table contains a number of entries which is a power of two. The +** "state" table (which follows) contains information about the starting +** point and size of each hash table. +*/ +struct yyActionEntry { + YYCODETYPE lookahead; /* The value of the look-ahead token */ + YYACTIONTYPE action; /* Action to take for this look-ahead */ + struct yyActionEntry *next; /* Next look-ahead with the same hash, or NULL */ +}; +static struct yyActionEntry yyActionTable[] = { +%% +}; + +/* The state table contains information needed to look up the correct +** action in the action table, given the current state of the parser. +** Information needed includes: +** +** + A pointer to the start of the action hash table in yyActionTable. +** +** + A mask used to hash the look-ahead token. The mask is an integer +** which is one less than the size of the hash table. +** +** + The default action. This is the action to take if no entry for +** the given look-ahead is found in the action hash table. +*/ +struct yyStateEntry { + struct yyActionEntry *hashtbl; /* Start of the hash table in yyActionTable */ + int mask; /* Mask used for hashing the look-ahead */ + YYACTIONTYPE actionDefault; /* Default action if look-ahead not found */ +}; +static struct yyStateEntry yyStateTable[] = { +%% +}; + +/* The following structure represents a single element of the +** parser's stack. Information stored includes: +** +** + The state number for the parser at this level of the stack. +** +** + The value of the token stored at this level of the stack. +** (In other words, the "major" token.) +** +** + The semantic value stored at this level of the stack. This is +** the information used by the action routines in the grammar. +** It is sometimes called the "minor" token. +*/ +struct yyStackEntry { + int stateno; /* The state-number */ + int major; /* The major token value. This is the code + ** number for the token at this stack level */ + YYMINORTYPE minor; /* The user-supplied minor token value. This + ** is the value of the token */ +}; + +/* The state of the parser is completely contained in an instance of +** the following structure */ +struct yyParser { + int idx; /* Index of top element in stack */ + int errcnt; /* Shifts left before out of the error */ + struct yyStackEntry *top; /* Pointer to the top stack element */ + struct yyStackEntry stack[YYSTACKDEPTH]; /* The parser's stack */ +}; +typedef struct yyParser yyParser; + +#ifndef NDEBUG +#include +static FILE *yyTraceFILE = 0; +static char *yyTracePrompt = 0; + +/* +** Turn parser tracing on by giving a stream to which to write the trace +** and a prompt to preface each trace message. Tracing is turned off +** by making either argument NULL +** +** Inputs: +**
    +**
  • A FILE* to which trace output should be written. +** If NULL, then tracing is turned off. +**
  • A prefix string written at the beginning of every +** line of trace output. If NULL, then tracing is +** turned off. +**
+** +** Outputs: +** None. +*/ +void ParseTrace(FILE *TraceFILE, char *zTracePrompt){ + yyTraceFILE = TraceFILE; + yyTracePrompt = zTracePrompt; + if( yyTraceFILE==0 ) yyTracePrompt = 0; + else if( yyTracePrompt==0 ) yyTraceFILE = 0; +} + +/* For tracing shifts, the names of all terminals and nonterminals +** are required. The following table supplies these names */ +static char *yyTokenName[] = { +%% +}; +#define YYTRACE(X) if( yyTraceFILE ) fprintf(yyTraceFILE,"%sReduce [%s].\n",yyTracePrompt,X); +#else +#define YYTRACE(X) +#endif + +/* +** This function allocates a new parser. +** The only argument is a pointer to a function which works like +** malloc. +** +** Inputs: +** A pointer to the function used to allocate memory. +** +** Outputs: +** A pointer to a parser. This pointer is used in subsequent calls +** to Parse and ParseFree. +*/ +void *ParseAlloc(void *(*mallocProc)()){ + yyParser *pParser; + pParser = (yyParser*)(*mallocProc)( sizeof(yyParser), __FILE__, __LINE__ ); + if( pParser ){ + pParser->idx = -1; + } + return pParser; +} + +/* The following function deletes the value associated with a +** symbol. The symbol can be either a terminal or nonterminal. +** "yymajor" is the symbol code, and "yypminor" is a pointer to +** the value. +*/ +static void yy_destructor(YYCODETYPE yymajor, YYMINORTYPE *yypminor){ + switch( yymajor ){ + /* Here is inserted the actions which take place when a + ** terminal or non-terminal is destroyed. This can happen + ** when the symbol is popped from the stack during a + ** reduce or during error processing or when a parser is + ** being destroyed before it is finished parsing. + ** + ** Note: during a reduce, the only symbols destroyed are those + ** which appear on the RHS of the rule, but which are not used + ** inside the C code. + */ +%% + default: break; /* If no destructor action specified: do nothing */ + } +} + +/* +** Pop the parser's stack once. +** +** If there is a destructor routine associated with the token which +** is popped from the stack, then call it. +** +** Return the major token number for the symbol popped. +*/ +static int yy_pop_parser_stack(yyParser *pParser){ + YYCODETYPE yymajor; + + if( pParser->idx<0 ) return 0; +#ifndef NDEBUG + if( yyTraceFILE && pParser->idx>=0 ){ + fprintf(yyTraceFILE,"%sPopping %s\n", + yyTracePrompt, + yyTokenName[pParser->top->major]); + } +#endif + yymajor = pParser->top->major; + yy_destructor( yymajor, &pParser->top->minor); + pParser->idx--; + pParser->top--; + return yymajor; +} + +/* +** Deallocate and destroy a parser. Destructors are all called for +** all stack elements before shutting the parser down. +** +** Inputs: +**
    +**
  • A pointer to the parser. This should be a pointer +** obtained from ParseAlloc. +**
  • A pointer to a function used to reclaim memory obtained +** from malloc. +**
+*/ +void ParseFree( + void *p, /* The parser to be deleted */ + void (*freeProc)() /* Function used to reclaim memory */ +){ + yyParser *pParser = (yyParser*)p; + if( pParser==0 ) return; + while( pParser->idx>=0 ) yy_pop_parser_stack(pParser); + (*freeProc)(pParser, __FILE__, __LINE__); +} + +/* +** Find the appropriate action for a parser given the look-ahead token. +** +** If the look-ahead token is YYNOCODE, then check to see if the action is +** independent of the look-ahead. If it is, return the action, otherwise +** return YY_NO_ACTION. +*/ +static int yy_find_parser_action( + yyParser *pParser, /* The parser */ + int iLookAhead /* The look-ahead token */ +){ + struct yyStateEntry *pState; /* Appropriate entry in the state table */ + struct yyActionEntry *pAction; /* Action appropriate for the look-ahead */ + + /* if( pParser->idx<0 ) return YY_NO_ACTION; */ + pState = &yyStateTable[pParser->top->stateno]; + if( iLookAhead!=YYNOCODE ){ + pAction = &pState->hashtbl[iLookAhead & pState->mask]; + while( pAction ){ + if( pAction->lookahead==iLookAhead ) return pAction->action; + pAction = pAction->next; + } + }else if( pState->mask!=0 || pState->hashtbl->lookahead!=YYNOCODE ){ + return YY_NO_ACTION; + } + return pState->actionDefault; +} + +/* +** Perform a shift action. +*/ +static void yy_shift( + yyParser *yypParser, /* The parser to be shifted */ + int yyNewState, /* The new state to shift in */ + int yyMajor, /* The major token to shift in */ + YYMINORTYPE *yypMinor /* Pointer ot the minor token to shift in */ +){ + yypParser->idx++; + yypParser->top++; + if( yypParser->idx>=YYSTACKDEPTH ){ + yypParser->idx--; + yypParser->top--; +#ifndef NDEBUG + if( yyTraceFILE ){ + fprintf(yyTraceFILE,"%sStack Overflow!\n",yyTracePrompt); + } +#endif + while( yypParser->idx>=0 ) yy_pop_parser_stack(yypParser); + /* Here code is inserted which will execute if the parser + ** stack every overflows */ +%% + return; + } + yypParser->top->stateno = yyNewState; + yypParser->top->major = yyMajor; + yypParser->top->minor = *yypMinor; +#ifndef NDEBUG + if( yyTraceFILE && yypParser->idx>0 ){ + int i; + fprintf(yyTraceFILE,"%sShift %d\n",yyTracePrompt,yyNewState); + fprintf(yyTraceFILE,"%sStack:",yyTracePrompt); + for(i=1; i<=yypParser->idx; i++) + fprintf(yyTraceFILE," %s",yyTokenName[yypParser->stack[i].major]); + fprintf(yyTraceFILE,"\n"); + } +#endif +} + +/* The following table contains information about every rule that +** is used during the reduce. +*/ +static struct { + YYCODETYPE lhs; /* Symbol on the left-hand side of the rule */ + unsigned char nrhs; /* Number of right-hand side symbols in the rule */ +} yyRuleInfo[] = { +%% +}; + +static void yy_accept(); /* Forward declaration */ + +/* +** Perform a reduce action and the shift that must immediately +** follow the reduce. +*/ +static void yy_reduce( + yyParser *yypParser, /* The parser */ + int yyruleno /* Number of the rule by which to reduce */ + ParseANSIARGDECL +){ + int yygoto; /* The next state */ + int yyact; /* The next action */ + YYMINORTYPE yygotominor; /* The LHS of the rule reduced */ + struct yyStackEntry *yymsp; /* The top of the parser's stack */ + int yysize; /* Amount to pop the stack */ + yymsp = yypParser->top; + switch( yyruleno ){ + /* Beginning here are the reduction cases. A typical example + ** follows: + ** case 0: + ** YYTRACE(""); + ** #line + ** { ... } // User supplied code + ** #line + ** break; + */ +%% + }; + yygoto = yyRuleInfo[yyruleno].lhs; + yysize = yyRuleInfo[yyruleno].nrhs; + yypParser->idx -= yysize; + yypParser->top -= yysize; + yyact = yy_find_parser_action(yypParser,yygoto); + if( yyact < YYNSTATE ){ + yy_shift(yypParser,yyact,yygoto,&yygotominor); + }else if( yyact == YYNSTATE + YYNRULE + 1 ){ + yy_accept(yypParser ParseARGDECL); + } +} + +/* +** The following code executes when the parse fails +*/ +static void yy_parse_failed( + yyParser *yypParser /* The parser */ + ParseANSIARGDECL /* Extra arguments (if any) */ +){ +#ifndef NDEBUG + if( yyTraceFILE ){ + fprintf(yyTraceFILE,"%sFail!\n",yyTracePrompt); + } +#endif + while( yypParser->idx>=0 ) yy_pop_parser_stack(yypParser); + /* Here code is inserted which will be executed whenever the + ** parser fails */ +%% +} + +/* +** The following code executes when a syntax error first occurs. +*/ +static void yy_syntax_error( + yyParser *yypParser, /* The parser */ + int yymajor, /* The major type of the error token */ + YYMINORTYPE yyminor /* The minor type of the error token */ + ParseANSIARGDECL /* Extra arguments (if any) */ +){ +#define TOKEN (yyminor.yy0) +%% +} + +/* +** The following is executed when the parser accepts +*/ +static void yy_accept( + yyParser *yypParser /* The parser */ + ParseANSIARGDECL /* Extra arguments (if any) */ +){ +#ifndef NDEBUG + if( yyTraceFILE ){ + fprintf(yyTraceFILE,"%sAccept!\n",yyTracePrompt); + } +#endif + while( yypParser->idx>=0 ) yy_pop_parser_stack(yypParser); + /* Here code is inserted which will be executed whenever the + ** parser accepts */ +%% +} + +/* The main parser program. +** The first argument is a pointer to a structure obtained from +** "ParseAlloc" which describes the current state of the parser. +** The second argument is the major token number. The third is +** the minor token. The fourth optional argument is whatever the +** user wants (and specified in the grammar) and is available for +** use by the action routines. +** +** Inputs: +**
    +**
  • A pointer to the parser (an opaque structure.) +**
  • The major token number. +**
  • The minor token number. +**
  • An option argument of a grammar-specified type. +**
+** +** Outputs: +** None. +*/ +void Parse( + void *yyp, /* The parser */ + int yymajor, /* The major token code number */ + ParseTOKENTYPE yyminor /* The value for the token */ + ParseANSIARGDECL +){ + YYMINORTYPE yyminorunion; + int yyact; /* The parser action. */ + int yyendofinput; /* True if we are at the end of input */ + int yyerrorhit = 0; /* True if yymajor has invoked an error */ + yyParser *yypParser; /* The parser */ + + /* (re)initialize the parser, if necessary */ + yypParser = (yyParser*)yyp; + if( yypParser->idx<0 ){ + if( yymajor==0 ) return; + yypParser->idx = 0; + yypParser->errcnt = -1; + yypParser->top = &yypParser->stack[0]; + yypParser->top->stateno = 0; + yypParser->top->major = 0; + } + yyminorunion.yy0 = yyminor; + yyendofinput = (yymajor==0); + +#ifndef NDEBUG + if( yyTraceFILE ){ + fprintf(yyTraceFILE,"%sInput %s\n",yyTracePrompt,yyTokenName[yymajor]); + } +#endif + + do{ + yyact = yy_find_parser_action(yypParser,yymajor); + if( yyacterrcnt--; + if( yyendofinput && yypParser->idx>=0 ){ + yymajor = 0; + }else{ + yymajor = YYNOCODE; + } + }else if( yyact < YYNSTATE + YYNRULE ){ + yy_reduce(yypParser,yyact-YYNSTATE ParseARGDECL); + }else if( yyact == YY_ERROR_ACTION ){ +#ifndef NDEBUG + if( yyTraceFILE ){ + fprintf(yyTraceFILE,"%sSyntax Error!\n",yyTracePrompt); + } +#endif +#ifdef YYERRORSYMBOL + /* A syntax error has occurred. + ** The response to an error depends upon whether or not the + ** grammar defines an error token "ERROR". + ** + ** This is what we do if the grammar does define ERROR: + ** + ** * Call the %syntax_error function. + ** + ** * Begin popping the stack until we enter a state where + ** it is legal to shift the error symbol, then shift + ** the error symbol. + ** + ** * Set the error count to three. + ** + ** * Begin accepting and shifting new tokens. No new error + ** processing will occur until three tokens have been + ** shifted successfully. + ** + */ + if( yypParser->errcnt<0 ){ + yy_syntax_error(yypParser,yymajor,yyminorunion ParseARGDECL); + } + if( yypParser->top->major==YYERRORSYMBOL || yyerrorhit ){ +#ifndef NDEBUG + if( yyTraceFILE ){ + fprintf(yyTraceFILE,"%sDiscard input token %s\n", + yyTracePrompt,yyTokenName[yymajor]); + } +#endif + yy_destructor(yymajor,&yyminorunion); + yymajor = YYNOCODE; + }else{ + while( + yypParser->idx >= 0 && + yypParser->top->major != YYERRORSYMBOL && + (yyact = yy_find_parser_action(yypParser,YYERRORSYMBOL)) >= YYNSTATE + ){ + yy_pop_parser_stack(yypParser); + } + if( yypParser->idx < 0 || yymajor==0 ){ + yy_destructor(yymajor,&yyminorunion); + yy_parse_failed(yypParser ParseARGDECL); + yymajor = YYNOCODE; + }else if( yypParser->top->major!=YYERRORSYMBOL ){ + YYMINORTYPE u2; + u2.YYERRSYMDT = 0; + yy_shift(yypParser,yyact,YYERRORSYMBOL,&u2); + } + } + yypParser->errcnt = 3; + yyerrorhit = 1; +#else /* YYERRORSYMBOL is not defined */ + /* This is what we do if the grammar does not define ERROR: + ** + ** * Report an error message, and throw away the input token. + ** + ** * If the input token is $, then fail the parse. + ** + ** As before, subsequent error messages are suppressed until + ** three input tokens have been successfully shifted. + */ + if( yypParser->errcnt<=0 ){ + yy_syntax_error(yypParser,yymajor,yyminorunion ParseARGDECL); + } + yypParser->errcnt = 3; + yy_destructor(yymajor,&yyminorunion); + if( yyendofinput ){ + yy_parse_failed(yypParser ParseARGDECL); + } + yymajor = YYNOCODE; +#endif + }else{ + yy_accept(yypParser ParseARGDECL); + yymajor = YYNOCODE; + } + }while( yymajor!=YYNOCODE && yypParser->idx>=0 ); + return; +}