--- /dev/null
+/*
+** 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 <stdio.h>
+#include <varargs.h>
+#include <string.h>
+#include <ctype.h>
+
+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; i<amt-1; i++) freelist[i].next = &freelist[i+1];
+ freelist[amt-1].next = 0;
+ }
+ new = freelist;
+ freelist = freelist->next;
+ 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; i<rp->nrhs; 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; i<lemp->nsymbol; i++){
+ lemp->symbols[i]->lambda = FALSE;
+ }
+ for(i=lemp->nterminal; i<lemp->nsymbol; 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; i<rp->nrhs; 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; i<rp->nrhs; 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; i<rp->nrhs; 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; i<lemp->nstate; 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; i<lemp->nstate; 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; i<lemp->nstate; i++){
+ for(cfp=lemp->sorted[i]->cfp; cfp; cfp=cfp->next){
+ cfp->status = INCOMPLETE;
+ }
+ }
+
+ do{
+ progress = 0;
+ for(i=0; i<lemp->nstate; 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; i<lemp->nstate; 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; j<lemp->nterminal; 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; i<lemp->nstate; 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; i<lemp->nstate; 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->prec<spy->prec ){
+ 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->prec<spy->prec ){
+ 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; i<amt-1; i++) freelist[i].next = &freelist[i+1];
+ freelist[amt-1].next = 0;
+ }
+ new = freelist;
+ freelist = freelist->next;
+ 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; i<rp->nrhs; 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=='-' && i<max-1 ) spot = i+1;
+ if( c==' ' ) spot = i;
+ }
+ return spot;
+}
+
+/*
+** The error message is split across multiple lines if necessary. The
+** splits occur at a space, if there is a space available near the end
+** of the line.
+*/
+#define ERRMSGSIZE 10000 /* Hope this is big enough. No way to error check */
+#define LINEWIDTH 79 /* Max width of any output line */
+#define PREFIXLIMIT 30 /* Max width of the prefix on each line */
+void ErrorMsg(va_alist)
+va_dcl
+{
+ char *filename;
+ int lineno;
+ char *format;
+ char errmsg[ERRMSGSIZE];
+ char prefix[PREFIXLIMIT+10];
+ int errmsgsize;
+ int prefixsize;
+ int availablewidth;
+ va_list ap;
+ int end, restart, base;
+
+ va_start(ap);
+ filename = va_arg(ap,char*);
+ lineno = va_arg(ap,int);
+ format = va_arg(ap,char*);
+ /* Prepare a prefix to be prepended to every output line */
+ if( lineno>0 ){
+ 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; i<LISTSIZE; i++) set[i] = 0;
+ while( list ){
+ ep = list;
+ list = NEXT(list);
+ NEXT(ep) = 0;
+ for(i=0; i<LISTSIZE-1 && set[i]!=0; i++){
+ ep = merge(ep,set[i],cmp,offset);
+ set[i] = 0;
+ }
+ set[i] = ep;
+ }
+ ep = 0;
+ for(i=0; i<LISTSIZE; i++) if( set[i] ) ep = merge(ep,set[i],cmp,offset);
+ return ep;
+}
+/************************ From the file "option.c" **************************/
+static char **argv;
+static struct s_options *op;
+static FILE *errstream;
+
+#define ISOPT(X) ((X)[0]=='-'||(X)[0]=='+'||strchr((X),'=')!=0)
+
+/*
+** Print the command line with a carrot pointing to the k-th character
+** of the n-th field.
+*/
+static void errline(n,k,err)
+int n;
+int k;
+FILE *err;
+{
+ int spcnt, i;
+ spcnt = 0;
+ if( argv[0] ) fprintf(err,"%s",argv[0]);
+ spcnt = strlen(argv[0]) + 1;
+ for(i=1; i<n && argv[i]; i++){
+ fprintf(err," %s",argv[i]);
+ spcnt += strlen(argv[i]+1);
+ }
+ spcnt += k;
+ for(; argv[i]; i++) fprintf(err," %s",argv[i]);
+ if( spcnt<20 ){
+ fprintf(err,"\n%*s^-- here\n",spcnt,"");
+ }else{
+ fprintf(err,"\n%*shere --^\n",spcnt-7,"");
+ }
+}
+
+/*
+** Return the index of the N-th non-switch argument. Return -1
+** if N is out of range.
+*/
+static int argindex(n)
+int n;
+{
+ int i;
+ int dashdash = 0;
+ if( argv!=0 && *argv!=0 ){
+ for(i=1; argv[i]; i++){
+ if( dashdash || !ISOPT(argv[i]) ){
+ if( n==0 ) return i;
+ n--;
+ }
+ if( strcmp(argv[i],"--")==0 ) dashdash = 1;
+ }
+ }
+ return -1;
+}
+
+static char emsg[] = "Command line syntax error: ";
+
+/*
+** Process a flag command line argument.
+*/
+static int handleflags(i,err)
+int i;
+FILE *err;
+{
+ int v;
+ int errcnt = 0;
+ int j;
+ for(j=0; op[j].label; j++){
+ if( strcmp(&argv[i][1],op[j].label)==0 ) break;
+ }
+ v = argv[i][0]=='-' ? 1 : 0;
+ if( op[j].label==0 ){
+ if( err ){
+ fprintf(err,"%sundefined option.\n",emsg);
+ errline(i,1,err);
+ }
+ errcnt++;
+ }else if( op[j].type==OPT_FLAG ){
+ *((int*)op[j].arg) = v;
+ }else if( op[j].type==OPT_FFLAG ){
+ (*(void(*)())(op[j].arg))(v);
+ }else{
+ if( err ){
+ fprintf(err,"%smissing argument on switch.\n",emsg);
+ errline(i,1,err);
+ }
+ errcnt++;
+ }
+ return errcnt;
+}
+
+/*
+** Process a command line switch which has an argument.
+*/
+static int handleswitch(i,err)
+int i;
+FILE *err;
+{
+ int lv = 0;
+ double dv = 0.0;
+ char *sv = 0, *end;
+ char *cp;
+ int j;
+ int errcnt = 0;
+ cp = strchr(argv[i],'=');
+ *cp = 0;
+ for(j=0; op[j].label; j++){
+ if( strcmp(argv[i],op[j].label)==0 ) break;
+ }
+ *cp = '=';
+ if( op[j].label==0 ){
+ if( err ){
+ fprintf(err,"%sundefined option.\n",emsg);
+ errline(i,0,err);
+ }
+ errcnt++;
+ }else{
+ cp++;
+ switch( op[j].type ){
+ case OPT_FLAG:
+ case OPT_FFLAG:
+ if( err ){
+ fprintf(err,"%soption requires an argument.\n",emsg);
+ errline(i,0,err);
+ }
+ errcnt++;
+ break;
+ case OPT_DBL:
+ case OPT_FDBL:
+ dv = strtod(cp,&end);
+ if( *end ){
+ if( err ){
+ fprintf(err,"%sillegal character in floating-point argument.\n",emsg);
+ errline(i,((int)end)-(int)argv[i],err);
+ }
+ errcnt++;
+ }
+ break;
+ case OPT_INT:
+ case OPT_FINT:
+ lv = strtol(cp,&end,0);
+ if( *end ){
+ if( err ){
+ fprintf(err,"%sillegal character in integer argument.\n",emsg);
+ errline(i,((int)end)-(int)argv[i],err);
+ }
+ errcnt++;
+ }
+ break;
+ case OPT_STR:
+ case OPT_FSTR:
+ sv = cp;
+ break;
+ }
+ switch( op[j].type ){
+ case OPT_FLAG:
+ case OPT_FFLAG:
+ break;
+ case OPT_DBL:
+ *(double*)(op[j].arg) = dv;
+ break;
+ case OPT_FDBL:
+ (*(void(*)())(op[j].arg))(dv);
+ break;
+ case OPT_INT:
+ *(int*)(op[j].arg) = lv;
+ break;
+ case OPT_FINT:
+ (*(void(*)())(op[j].arg))((int)lv);
+ break;
+ case OPT_STR:
+ *(char**)(op[j].arg) = sv;
+ break;
+ case OPT_FSTR:
+ (*(void(*)())(op[j].arg))(sv);
+ break;
+ }
+ }
+ return errcnt;
+}
+
+int optinit(a,o,err)
+char **a;
+struct s_options *o;
+FILE *err;
+{
+ int errcnt = 0;
+ argv = a;
+ op = o;
+ errstream = err;
+ if( argv && *argv && op ){
+ int i;
+ for(i=1; argv[i]; i++){
+ if( argv[i][0]=='+' || argv[i][0]=='-' ){
+ errcnt += handleflags(i,err);
+ }else if( strchr(argv[i],'=') ){
+ errcnt += handleswitch(i,err);
+ }
+ }
+ }
+ if( errcnt>0 ){
+ fprintf(err,"Valid command line options for \"%s\" are:\n",*a);
+ optprint();
+ exit(1);
+ }
+ return 0;
+}
+
+int optnargs(){
+ int cnt = 0;
+ int dashdash = 0;
+ int i;
+ if( argv!=0 && argv[0]!=0 ){
+ for(i=1; argv[i]; i++){
+ if( dashdash || !ISOPT(argv[i]) ) cnt++;
+ if( strcmp(argv[i],"--")==0 ) dashdash = 1;
+ }
+ }
+ return cnt;
+}
+
+char *optarg(n)
+int n;
+{
+ int i;
+ i = argindex(n);
+ return i>=0 ? argv[i] : 0;
+}
+
+void opterr(n)
+int n;
+{
+ int i;
+ i = argindex(n);
+ if( i>=0 ) errline(i,0,errstream);
+}
+
+void optprint(){
+ int i;
+ int max, len;
+ max = 0;
+ for(i=0; op[i].label; i++){
+ len = strlen(op[i].label) + 1;
+ switch( op[i].type ){
+ case OPT_FLAG:
+ case OPT_FFLAG:
+ break;
+ case OPT_INT:
+ case OPT_FINT:
+ len += 9; /* length of "<integer>" */
+ break;
+ case OPT_DBL:
+ case OPT_FDBL:
+ len += 6; /* length of "<real>" */
+ break;
+ case OPT_STR:
+ case OPT_FSTR:
+ len += 8; /* length of "<string>" */
+ break;
+ }
+ if( len>max ) max = len;
+ }
+ for(i=0; op[i].label; i++){
+ switch( op[i].type ){
+ case OPT_FLAG:
+ case OPT_FFLAG:
+ fprintf(errstream," -%-*s %s\n",max,op[i].label,op[i].message);
+ break;
+ case OPT_INT:
+ case OPT_FINT:
+ fprintf(errstream," %s=<integer>%*s %s\n",op[i].label,
+ max-strlen(op[i].label)-9,"",op[i].message);
+ break;
+ case OPT_DBL:
+ case OPT_FDBL:
+ fprintf(errstream," %s=<real>%*s %s\n",op[i].label,
+ max-strlen(op[i].label)-6,"",op[i].message);
+ break;
+ case OPT_STR:
+ case OPT_FSTR:
+ fprintf(errstream," %s=<string>%*s %s\n",op[i].label,
+ max-strlen(op[i].label)-8,"",op[i].message);
+ break;
+ }
+ }
+}
+/*********************** From the file "parse.c" ****************************/
+/*
+** Input file parser for the LEMON parser generator.
+*/
+
+/* The state of the parser */
+struct pstate {
+ char *filename; /* Name of the input file */
+ int tokenlineno; /* Linenumber at which current token starts */
+ int errorcnt; /* Number of errors so far */
+ char *tokenstart; /* Text of current token */
+ struct lemon *gp; /* Global state vector */
+ enum e_state {
+ INITIALIZE,
+ WAITING_FOR_DECL_OR_RULE,
+ WAITING_FOR_DECL_KEYWORD,
+ WAITING_FOR_DECL_ARG,
+ WAITING_FOR_PRECEDENCE_SYMBOL,
+ WAITING_FOR_ARROW,
+ IN_RHS,
+ LHS_ALIAS_1,
+ LHS_ALIAS_2,
+ LHS_ALIAS_3,
+ RHS_ALIAS_1,
+ RHS_ALIAS_2,
+ PRECEDENCE_MARK_1,
+ PRECEDENCE_MARK_2,
+ RESYNC_AFTER_RULE_ERROR,
+ RESYNC_AFTER_DECL_ERROR,
+ WAITING_FOR_DESTRUCTOR_SYMBOL,
+ WAITING_FOR_DATATYPE_SYMBOL
+ } state; /* The state of the parser */
+ struct symbol *lhs; /* Left-hand side of current rule */
+ char *lhsalias; /* Alias for the LHS */
+ int nrhs; /* Number of right-hand side symbols seen */
+ struct symbol *rhs[MAXRHS]; /* RHS symbols */
+ char *alias[MAXRHS]; /* Aliases for each RHS symbol (or NULL) */
+ struct rule *prevrule; /* Previous rule parsed */
+ char *declkeyword; /* Keyword of a declaration */
+ char **declargslot; /* Where the declaration argument should be put */
+ int *decllnslot; /* Where the declaration linenumber is put */
+ enum e_assoc declassoc; /* Assign this association to decl arguments */
+ int preccounter; /* Assign this precedence to decl arguments */
+ struct rule *firstrule; /* Pointer to first rule in the grammar */
+ struct rule *lastrule; /* Pointer to the most recently parsed rule */
+};
+
+/* Parse a single token */
+static void parseonetoken(psp)
+struct pstate *psp;
+{
+ char *x;
+ x = Strsafe(psp->tokenstart); /* Save the token permanently */
+#if 0
+ printf("%s:%d: Token=[%s] state=%d\n",psp->filename,psp->tokenlineno,
+ x,psp->state);
+#endif
+ switch( psp->state ){
+ case INITIALIZE:
+ psp->prevrule = 0;
+ psp->preccounter = 0;
+ psp->firstrule = psp->lastrule = 0;
+ psp->gp->nrule = 0;
+ /* Fall thru to next case */
+ case WAITING_FOR_DECL_OR_RULE:
+ if( x[0]=='%' ){
+ psp->state = 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; i<psp->nrhs; 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; i<amt-1; i++) plink_freelist[i].next = &plink_freelist[i+1];
+ plink_freelist[amt-1].next = 0;
+ }
+ new = plink_freelist;
+ plink_freelist = plink_freelist->next;
+ 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; i<lemp->nsymbol; 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; i<skip; i++){
+ printf("//");
+ for(j=i; j<lemp->nsymbol; 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; i<rp->nrhs; 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; i<lemp->nterminal; 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; i<lemp->nstate; 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; i<rp->nrhs; 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; i<rp->nrhs; 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; i<rp->nrhs; 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; i<arraysize; i++) types[i] = 0;
+ maxdtlength = 0;
+ for(i=0; i<lemp->nsymbol; 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; i<lemp->nsymbol; 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; i<arraysize; i++){
+ if( types[i]==0 ) continue;
+ fprintf(out," %s yy%d;\n",types[i],i+1); lineno++;
+ free(types[i]);
+ }
+ fprintf(out," int yy%d;\n",lemp->errsym->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; i<lemp->nterminal; 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; i<lemp->nstate; 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( tablesize<stp->naction ) tablesize += tablesize;
+ assert( tablesize<= sizeof(table)/sizeof(table[0]) );
+ for(j=0; j<tablesize; j++){
+ table[j] = 0;
+ collide[j] = -1;
+ }
+
+ /* Hash the actions into the hash table */
+ stp->tabdfltact = 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; j<tablesize; j++){
+ if( table[j] && table[j]->collide ){
+ while( table[k] ) k++;
+ table[k] = table[j]->collide;
+ collide[j] = k;
+ table[j]->collide = 0;
+ if( k<j ) j = k-1;
+ }
+ }
+
+ /* Print the hash table */
+ fprintf(out,"/* State %d */\n",stp->index); lineno++;
+ for(j=0; j<tablesize; j++){
+ if( table[j]==0 ){
+ fprintf(out,
+ " {YYNOCODE,0,0}, /* Unused */\n");
+ }else{
+ fprintf(out," {%4d,%4d, ",
+ table[j]->sp->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; i<lemp->nstate; i++){
+ int tablesize;
+ stp = lemp->sorted[i];
+ tablesize = 1;
+ while( tablesize<stp->naction ) 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; i<lemp->nsymbol; 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; i<lemp->nsymbol; 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; i<lemp->nsymbol && lemp->symbols[i]->type!=TERMINAL; i++);
+ if( i<lemp->nsymbol ){
+ emit_destructor_code(out,lemp->symbols[i],lemp,&lineno);
+ fprintf(out," break;\n"); lineno++;
+ }
+ }
+ for(i=0; i<lemp->nsymbol; 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; i<rp->nrhs; 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; i<lemp->nterminal && 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; i<lemp->nterminal; 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; i<lemp->nstate; 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; i<size; i++) s[i] = 0;
+ return s;
+}
+
+/* Deallocate a set */
+void SetFree(s)
+char *s;
+{
+ free(s);
+}
+
+/* Add a new element to the set. Return TRUE if the element was added
+** and FALSE if it was already there. */
+int SetAdd(s,e)
+char *s;
+int e;
+{
+ int rv;
+ rv = s[e];
+ s[e] = 1;
+ return !rv;
+}
+
+/* Add every element of s2 to s1. Return TRUE if s1 changes. */
+int SetUnion(s1,s2)
+char *s1;
+char *s2;
+{
+ int i, progress;
+ progress = 0;
+ for(i=0; i<size; i++){
+ if( s2[i]==0 ) continue;
+ if( s1[i]==0 ){
+ progress = 1;
+ s1[i] = 1;
+ }
+ }
+ return progress;
+}
+/********************** From the file "table.c" ****************************/
+/*
+** 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.
+*/
+
+PRIVATE int strhash(x)
+char *x;
+{
+ int h = 0;
+ while( *x) h = h*13 + *(x++);
+ return h;
+}
+
+/* Works like strdup, sort of. Save a string in malloced memory, but
+** keep strings in a table so that the same string is not in more
+** than one place.
+*/
+char *Strsafe(y)
+char *y;
+{
+ char *z;
+
+ z = Strsafe_find(y);
+ if( z==0 && (z=malloc( strlen(y)+1 ))!=0 ){
+ strcpy(z,y);
+ Strsafe_insert(z);
+ }
+ MemoryCheck(z);
+ return z;
+}
+
+/* There is one instance of the following structure for each
+** associative array of type "x1".
+*/
+struct s_x1 {
+ 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_x1node *tbl; /* The data stored here */
+ struct s_x1node **ht; /* Hash table for lookups */
+};
+
+/* There is one instance of this structure for every data element
+** in an associative array of type "x1".
+*/
+typedef struct s_x1node {
+ char *data; /* The data */
+ struct s_x1node *next; /* Next entry with the same hash */
+ struct s_x1node **from; /* Previous link */
+} x1node;
+
+/* There is only one instance of the array, which is the following */
+static struct s_x1 *x1a;
+
+/* Allocate a new associative array */
+void Strsafe_init(){
+ if( x1a ) return;
+ x1a = (struct s_x1*)malloc( sizeof(struct s_x1) );
+ if( x1a ){
+ x1a->size = 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; i<size; i++) array.ht[i] = 0;
+ for(i=0; i<x1a->count; 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; i<size; i++) array.ht[i] = 0;
+ for(i=0; i<x2a->count; 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; i<size; i++) array[i] = x2a->tbl[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; i<size; i++) array.ht[i] = 0;
+ for(i=0; i<x3a->count; 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; i<size; i++) array[i] = x3a->tbl[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; i<size; i++) array.ht[i] = 0;
+ for(i=0; i<x4a->count; 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; i<x4a->count; i++) (*f)(x4a->tbl[i].data);
+ for(i=0; i<x4a->size; i++) x4a->ht[i] = 0;
+ x4a->count = 0;
+ return;
+}
--- /dev/null
+<html>
+<head>
+<title>The Lemon Parser Generator</title>
+</head>
+<body bgcolor=white>
+<h1 align=center>The Lemon Parser Generator</h1>
+
+<p>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.</p>
+
+<p>This document is an introduction to the Lemon
+parser generator.</p>
+
+<h2>Theory of Operation</h2>
+
+<p>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:
+<ul>
+<li>The grammar specification.
+<li>A parser template file.
+</ul>
+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.</p>
+
+<p>Depending on command-line options, Lemon will generate between
+one and three files of outputs.
+<ul>
+<li>C code to implement the parser.
+<li>A header file defining an integer ID for each terminal symbol.
+<li>An information file that describes the states of the generated parser
+ automaton.
+</ul>
+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.</p>
+
+<p>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:
+<pre>
+ lemon gram.y
+</pre>
+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.</p>
+
+<h3>Command Line Options</h3>
+
+<p>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
+<pre>
+ lemon -?
+</pre>
+As of this writing, the following command-line options are supported:
+<ul>
+<li><tt>-b</tt>
+<li><tt>-c</tt>
+<li><tt>-g</tt>
+<li><tt>-m</tt>
+<li><tt>-q</tt>
+<li><tt>-s</tt>
+<li><tt>-x</tt>
+</ul>
+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:
+<pre>
+ Parser statistics: 74 terminals, 70 nonterminals, 179 rules
+ 340 states, 2026 parser table entries, 0 conflicts
+</pre>
+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.</p>
+
+<h3>The Parser Interface</h3>
+
+<p>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.</p>
+
+<p>Before a program begins using a Lemon-generated parser, the program
+must first create the parser.
+A new parser is created as follows:
+<pre>
+ void *pParser = ParseAlloc( malloc );
+</pre>
+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()''.</p>
+
+<p>After a program is finished using a parser, it can reclaim all
+memory allocated by that parser by calling
+<pre>
+ ParseFree(pParser, free);
+</pre>
+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.</p>
+
+<p>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:
+<pre>
+ Parse(pParser, hTokenID, sTokenData, pArg);
+</pre>
+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.</p>
+
+<p>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.</p>
+
+<p>A typical use of a Lemon parser might look something like the
+following:
+<pre>
+ 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 }
+</pre>
+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. </p>
+
+<p>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.</p>
+
+<p>The core of this example as it relates to Lemon is as follows:
+<pre>
+ ParseFile(){
+ pParser = ParseAlloc( malloc );
+ while( GetNextToken(pTokenizer,&hTokenId, &sToken) ){
+ Parse(pParser, hTokenId, sToken);
+ }
+ Parse(pParser, 0, sToken);
+ ParseFree(pParser, free );
+ }
+</pre>
+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().</p>
+
+<p>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:
+<pre>
+ ParseTrace(FILE *stream, char *zPrefix);
+</pre>
+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).</p>
+
+<h3>Differences With YACC and BISON</h3>
+
+<p>Programmers who have previously used the yacc or bison parser
+generator will notice several important differences between yacc and/or
+bison and Lemon.
+<ul>
+<li>In yacc and bison, the parser calls the tokenizer. In Lemon,
+ the tokenizer calls the parser.
+<li>Lemon uses no global variables. Yacc and bison use global variables
+ to pass information between the tokenizer and parser.
+<li>Lemon allows multiple parsers to be running simultaneously. Yacc
+ and bison do not.
+</ul>
+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.</p>
+
+<h2>Input File Syntax</h2>
+
+<p>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.</p>
+
+<p>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++.</p>
+
+<h3>Terminals and Nonterminals</h3>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<h3>Grammar Rules</h3>
+
+<p>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 <tt>%start</tt> directive described below.)
+A typical sequence of grammar rules might look something like this:
+<pre>
+ expr ::= expr PLUS expr.
+ expr ::= expr TIMES expr.
+ expr ::= LPAREN expr RPAREN.
+ expr ::= VALUE.
+</pre>
+</p>
+
+<p>There is one non-terminal in this example, ``expr'', and five
+terminal symbols or tokens: ``PLUS'', ``TIMES'', ``LPAREN'',
+``RPAREN'' and ``VALUE''.</p>
+
+<p>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 <tt>{...}</tt>) immediately after the
+period that closes the rule.
+For example:
+<pre>
+ expr ::= expr PLUS expr. { printf("Doing an addition...\n"); }
+</pre>
+</p>
+
+<p>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 ``$$'' in the
+action to stand for the value of the left-hand side of the rule and
+symbols ``$1'', ``$2'', and so forth to stand for the value of
+the terminal or nonterminal at position 1, 2 and so forth on the
+right-hand side of the rule.
+This idea is very powerful, but it is also very error-prone. The
+single most common source of errors in a yacc or bison grammar is
+to miscount the number of symbols on the right-hand side of a grammar
+rule and say ``$7'' when you really mean ``$8''.</p>
+
+<p>Lemon avoids the need to count grammar symbols by assigning symbolic
+names to each symbol in a grammar rule and then using those symbolic
+names in the action.
+In yacc or bison, one would write this:
+<pre>
+ expr -> expr PLUS expr { $$ = $1 + $3; };
+</pre>
+But in Lemon, the same rule becomes the following:
+<pre>
+ expr(A) ::= expr(B) PLUS expr(C). { A = B+C; }
+</pre>
+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.<p>
+
+<p>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
+<pre>
+ expr(A) ::= expr(B) PLUS expr(C). { A = B; }
+</pre>
+will generate an error because the linking symbol ``C'' is used
+in the grammar rule but not in the reduce action.</p>
+
+<p>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.</p>
+
+<h3>Precedence Rules</h3>
+
+<p>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.</p>
+
+<p>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:</p>
+
+<p><pre>
+ %left AND.
+ %left OR.
+ %nonassoc EQ NE GT GE LT LE.
+ %left PLUS MINUS.
+ %left TIMES DIVIDE MOD.
+ %right EXP NOT.
+</pre></p>
+
+<p>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
+<pre>
+ a AND b OR c
+</pre>
+like this
+<pre>
+ a AND (b OR c).
+</pre>
+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
+<pre>
+ a AND b AND c
+</pre>
+is parsed like this
+<pre>
+ (a AND b) AND c.
+</pre>
+The EXP operator is right-associative, though, so
+<pre>
+ a EXP b EXP c
+</pre>
+is parsed like this
+<pre>
+ a EXP (b EXP c).
+</pre>
+The nonassoc precedence is used for non-associative operators.
+So
+<pre>
+ a EQ b EQ c
+</pre>
+is an error.</p>
+
+<p>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:</p>
+
+<p><pre>
+ expr = MINUS expr. [NOT]
+</pre></p>
+
+<p>This rule has a precedence equal to that of the NOT symbol, not the
+MINUS symbol as would have been the case by default.</p>
+
+<p>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:
+<ul>
+<li> 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.
+<li> 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.
+<li> 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.
+<li> 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.
+<li> 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.
+<li> Otherwise, resolve the conflict by doing the shift and
+ report the parsing conflict.
+</ul>
+Reduce-reduce conflicts are resolved this way:
+<ul>
+<li> 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.
+<li> 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.
+<li> Otherwise, resolve the conflict by reducing by the rule that
+ appears first in the grammar and report a parsing conflict.
+</ul>
+
+<h3>Special Directives</h3>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>Lemon supports the following special directives:
+<ul>
+<li><tt>%destructor</tt>
+<li><tt>%extra_argument</tt>
+<li><tt>%include</tt>
+<li><tt>%left</tt>
+<li><tt>%name</tt>
+<li><tt>%nonassoc</tt>
+<li><tt>%parse_accept</tt>
+<li><tt>%parse_failure </tt>
+<li><tt>%right</tt>
+<li><tt>%stack_overflow</tt>
+<li><tt>%stack_size</tt>
+<li><tt>%start_symbol</tt>
+<li><tt>%syntax_error</tt>
+<li><tt>%token_destructor</tt>
+<li><tt>%token_prefix</tt>
+<li><tt>%token_type</tt>
+<li><tt>%type</tt>
+</ul>
+Each of these directives will be described separately in the
+following sections:</p>
+
+<h4>The <tt>%destructor</tt> directive</h4>
+
+<p>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.)</p>
+
+<p>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:
+<ul>
+<li> When a rule reduces and the value of a non-terminal on
+ the right-hand side is not linked to C code.
+<li> When the stack is popped during error processing.
+<li> When the ParseFree() function runs.
+</ul>
+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.</p>
+
+<p>Consider an example:
+<pre>
+ %type nt {void*}
+ %destructor nt { free($$); }
+ nt(A) ::= ID NUM. { A = malloc( 100 ); }
+</pre>
+This example is a bit contrived but it serves to illustrate how
+destructors work. The example shows a non-terminal named
+``nt'' that holds values of type ``void*''. When the rule for
+an ``nt'' reduces, it sets the value of the non-terminal to
+space obtained from malloc(). Later, when the nt non-terminal
+is popped from the stack, the destructor will fire and call
+free() on this malloced space, thus avoiding a memory leak.
+(Note that the symbol ``$$'' in the destructor code is replaced
+by the value of the non-terminal.)</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<h4>The <tt>%extra_argument</tt> directive</h4>
+
+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:</p>
+
+<p><pre>
+ %extra_argument { MyStruct *pAbc }
+</pre></p>
+
+<p>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().</p>
+
+<h4>The <tt>%include</tt> directive</h4>
+
+<p>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.</p>
+
+<p>The %include directive is very handy for getting some extra #include
+preprocessor statements at the beginning of the generated parser.
+For example:</p>
+
+<p><pre>
+ %include {#include <unistd.h>}
+</pre></p>
+
+<p>This might be needed, for example, if some of the C actions in the
+grammar call functions that are prototyed in unistd.h.</p>
+
+<h4>The <tt>%left</tt> directive</h4>
+
+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:</p>
+
+<p><pre>
+ %left AND.
+ %left OR.
+ %nonassoc EQ NE GT GE LT LE.
+ %left PLUS MINUS.
+ %left TIMES DIVIDE MOD.
+ %right EXP NOT.
+</pre></p>
+
+<p>Note the period that terminates each %left, %right or %nonassoc
+directive.</p>
+
+<p>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.</p>
+
+<h4>The <tt>%name</tt> directive</h4>
+
+<p>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:</p>
+
+<p><pre>
+ %name Abcde
+</pre></p>
+
+<p>Putting this directive in the grammar file will cause Lemon to generate
+functions named
+<ul>
+<li> AbcdeAlloc(),
+<li> AbcdeFree(),
+<li> AbcdeTrace(), and
+<li> Abcde().
+</ul>
+The %name directive allows you to generator two or more different
+parsers and link them all into the same executable.
+</p>
+
+<h4>The <tt>%nonassoc</tt> directive</h4>
+
+<p>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.</p>
+
+<h4>The <tt>%parse_accept</tt> directive</h4>
+
+<p>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.</p>
+
+<p>For example:</p>
+
+<p><pre>
+ %parse_accept {
+ printf("parsing complete!\n");
+ }
+</pre></p>
+
+
+<h4>The <tt>%parse_failure</tt> directive</h4>
+
+<p>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.</p>
+
+<p><pre>
+ %parse_failure {
+ fprintf(stderr,"Giving up. Parser is hopelessly lost...\n");
+ }
+</pre></p>
+
+<h4>The <tt>%right</tt> directive</h4>
+
+<p>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.</p>
+
+<h4>The <tt>%stack_overflow</tt> directive</h4>
+
+<p>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.</p>
+
+<p><pre>
+ %stack_overflow {
+ fprintf(stderr,"Giving up. Parser stack overflow\n");
+ }
+</pre></p>
+
+<p>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:
+<pre>
+ list ::= list element. // left-recursion. Good!
+ list ::= .
+</pre>
+Not like this:
+<pre>
+ list ::= element list. // right-recursion. Bad!
+ list ::= .
+</pre>
+
+<h4>The <tt>%stack_size</tt> directive</h4>
+
+<p>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.</p>
+
+<p><pre>
+ %stack_size 2000
+</pre></p>
+
+<h4>The <tt>%start_symbol</tt> directive</h4>
+
+<p>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.</p>
+
+<p><pre>
+ %start_symbol prog
+</pre></p>
+
+<h4>The <tt>%token_destructor</tt> directive</h4>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<h4>The <tt>%token_prefix</tt> directive</h4>
+
+<p>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:
+<pre>
+ #define AND 1
+ #define MINUS 2
+ #define OR 3
+ #define PLUS 4
+</pre>
+You can insert a statement into the grammar like this:
+<pre>
+ %token_prefix TOKEN_
+</pre>
+to cause Lemon to produce these symbols instead:
+<pre>
+ #define TOKEN_AND 1
+ #define TOKEN_MINUS 2
+ #define TOKEN_OR 3
+ #define TOKEN_PLUS 4
+</pre>
+
+<h4>The <tt>%token_type</tt> and <tt>%type</tt> directives</h4>
+
+<p>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:</p>
+
+<p><pre>
+ %token_type {Token*}
+</pre></p>
+
+<p>If the data type of terminals is not specified, the default value
+is ``int''.</p>
+
+<p>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:</p>
+
+<p><pre>
+ %type expr {Expr*}
+</pre></p>
+
+<p>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.</p>
+
+<h3>Error Processing</h3>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+</body>
+</html>
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