1 /*-------------------------------------------------------------------------
4 * routines to convert a string (legal ascii representation of node) back
7 * Copyright (c) 1994, Regents of the University of California
11 * $Header: /cvsroot/pgsql/src/backend/nodes/read.c,v 1.2 1996/11/08 05:56:48 momjian Exp $
14 * AUTHOR DATE MAJOR EVENT
15 * Andrew Yu Nov 2, 1994 file creation
17 *-------------------------------------------------------------------------
23 #include "nodes/pg_list.h"
24 #include "nodes/readfuncs.h"
25 #include "utils/elog.h"
29 * returns a Node with a given legal ascii representation
32 stringToNode(char *str)
36 (void) lsptok(str, NULL); /* set the string used in lsptok */
37 retval = nodeRead(true); /* start reading */
42 /*****************************************************************************
44 * the lisp token parser
46 *****************************************************************************/
48 #define RIGHT_PAREN (1000000 + 1)
49 #define LEFT_PAREN (1000000 + 2)
50 #define PLAN_SYM (1000000 + 3)
51 #define AT_SYMBOL (1000000 + 4)
52 #define ATOM_TOKEN (1000000 + 5)
56 * returns the type of the node token contained in token.
57 * It returns one of the following valid NodeTags:
58 * T_Integer, T_Float, T_String
59 * and some of its own:
60 * RIGHT_PAREN, LEFT_PAREN, PLAN_SYM, AT_SYMBOL, ATOM_TOKEN
62 * Assumption: the ascii representation is legal
65 nodeTokenType(char *token, int length)
70 * Check if the token is a number (decimal or integer,
71 * positive or negative
73 if (isdigit(*token) ||
74 (length>=2 && *token=='-' && isdigit(*(token+1)) ))
77 * skip the optional '-' (i.e. negative number)
84 * See if there is a decimal point
87 for (; length && *token != '.'; token++, length--);
90 * if there isn't, token's an int, otherwise it's a float.
93 retval = (*token != '.') ? T_Integer : T_Float;
95 else if (isalpha(*token))
97 else if (*token == '(')
99 else if (*token == ')')
100 retval = RIGHT_PAREN;
101 else if (*token == '@')
103 else if (*token == '\"')
105 else if (*token == '{')
111 * Works kinda like strtok, except it doesn't put nulls into string.
113 * Returns the length in length instead. The string can be set without
114 * returning a token by calling lsptok with length == NULL.
118 lsptok(char *string, int *length)
120 static char *local_str;
123 if (string != NULL) {
125 if (length == NULL) {
130 for (; *local_str == ' '
131 || *local_str == '\n'
132 || *local_str == '\t'; local_str++);
135 * Now pointing at next token.
137 ret_string = local_str;
138 if (*local_str == '\0') return(NULL);
141 if (*local_str == '\"') {
142 for (local_str++; *local_str != '\"'; (*length)++, local_str++);
143 (*length)++; local_str++;
144 }else if (*local_str == ')' || *local_str == '(' ||
145 *local_str == '}' || *local_str == '{') {
148 for (; *local_str != ' '
149 && *local_str != '\n'
150 && *local_str != '\t'
154 && *local_str != ')'; local_str++, (*length)++);
161 * This guy does all the reading.
163 * Secrets: He assumes that lsptok already has the string (see below).
164 * Any callers should set read_car_only to true.
167 nodeRead(bool read_car_only)
171 Node *this_value = NULL, *return_value = NULL;
174 bool make_dotted_pair_cell = false;
176 token = lsptok(NULL, &tok_len);
178 if (token == NULL) return(NULL);
180 type = nodeTokenType(token, tok_len);
184 this_value = parsePlanString();
185 token = lsptok(NULL, &tok_len);
186 if (token[0] != '}') return(NULL);
189 make_dotted_pair_cell = true;
191 make_dotted_pair_cell = false;
194 if (!read_car_only) {
195 List *l = makeNode(List);
197 lfirst(l) = nodeRead(false);
198 lnext(l) = nodeRead(false);
199 this_value = (Node*)l;
201 this_value = nodeRead(false);
210 if (!strncmp(token, "nil", 3)) {
213 * It might be "nil" but it is an atom!
216 make_dotted_pair_cell = false;
218 make_dotted_pair_cell = true;
221 tmp = token[tok_len];
222 token[tok_len] = '\0';
223 this_value = (Node*)pstrdup(token); /* !attention! not a Node.
225 token[tok_len] = tmp;
226 make_dotted_pair_cell = true;
230 tmp = token[tok_len];
231 token[tok_len] = '\0';
232 this_value = (Node*)makeFloat(atof(token));
233 token[tok_len] = tmp;
234 make_dotted_pair_cell = true;
237 tmp = token[tok_len];
238 token[tok_len] = '\0';
239 this_value = (Node*)makeInteger(atoi(token));
240 token[tok_len] = tmp;
241 make_dotted_pair_cell = true;
244 tmp = token[tok_len - 1];
245 token[tok_len - 1] = '\0';
247 this_value = (Node*)makeString(token); /* !! not strdup'd */
248 token[tok_len - 2] = tmp;
249 make_dotted_pair_cell = true;
252 elog(WARN, "nodeRead: Bad type %d", type);
255 if (make_dotted_pair_cell) {
256 List *l = makeNode(List);
258 lfirst(l) = this_value;
259 if (!read_car_only) {
260 lnext(l) = nodeRead(false);
264 return_value = (Node*)l;
266 return_value = this_value;
268 return(return_value);