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 1.5 1997/09/08 02:23:43 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 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, positive or
73 if (isdigit(*token) ||
74 (length >= 2 && *token == '-' && isdigit(*(token + 1))))
78 * skip the optional '-' (i.e. negative number)
86 * See if there is a decimal point
89 for (; length && *token != '.'; token++, length--);
92 * if there isn't, token's an int, otherwise it's a float.
95 retval = (*token != '.') ? T_Integer : T_Float;
97 else if (isalpha(*token))
99 else if (*token == '(')
101 else if (*token == ')')
102 retval = RIGHT_PAREN;
103 else if (*token == '@')
105 else if (*token == '\"')
107 else if (*token == '{')
113 * Works kinda like strtok, except it doesn't put nulls into string.
115 * Returns the length in length instead. The string can be set without
116 * returning a token by calling lsptok with length == NULL.
120 lsptok(char *string, int *length)
122 static char *local_str;
134 for (; *local_str == ' '
135 || *local_str == '\n'
136 || *local_str == '\t'; local_str++);
139 * Now pointing at next token.
141 ret_string = local_str;
142 if (*local_str == '\0')
146 if (*local_str == '\"')
148 for (local_str++; *local_str != '\"'; (*length)++, local_str++);
152 else if (*local_str == ')' || *local_str == '(' ||
153 *local_str == '}' || *local_str == '{')
159 for (; *local_str != ' '
160 && *local_str != '\n'
161 && *local_str != '\t'
165 && *local_str != ')'; local_str++, (*length)++);
172 * This guy does all the reading.
174 * Secrets: He assumes that lsptok already has the string (see below).
175 * Any callers should set read_car_only to true.
178 nodeRead(bool read_car_only)
182 Node *this_value = NULL,
183 *return_value = NULL;
186 bool make_dotted_pair_cell = false;
188 token = lsptok(NULL, &tok_len);
193 type = nodeTokenType(token, tok_len);
198 this_value = parsePlanString();
199 token = lsptok(NULL, &tok_len);
204 make_dotted_pair_cell = true;
206 make_dotted_pair_cell = false;
211 List *l = makeNode(List);
213 lfirst(l) = nodeRead(false);
214 lnext(l) = nodeRead(false);
215 this_value = (Node *) l;
219 this_value = nodeRead(false);
228 if (!strncmp(token, "nil", 3))
233 * It might be "nil" but it is an atom!
237 make_dotted_pair_cell = false;
241 make_dotted_pair_cell = true;
246 tmp = token[tok_len];
247 token[tok_len] = '\0';
248 this_value = (Node *) pstrdup(token); /* !attention! not a
251 token[tok_len] = tmp;
252 make_dotted_pair_cell = true;
256 tmp = token[tok_len];
257 token[tok_len] = '\0';
258 this_value = (Node *) makeFloat(atof(token));
259 token[tok_len] = tmp;
260 make_dotted_pair_cell = true;
263 tmp = token[tok_len];
264 token[tok_len] = '\0';
265 this_value = (Node *) makeInteger(atoi(token));
266 token[tok_len] = tmp;
267 make_dotted_pair_cell = true;
270 tmp = token[tok_len - 1];
271 token[tok_len - 1] = '\0';
273 this_value = (Node *) makeString(token); /* !! not strdup'd */
274 token[tok_len - 2] = tmp;
275 make_dotted_pair_cell = true;
278 elog(WARN, "nodeRead: Bad type %d", type);
281 if (make_dotted_pair_cell)
283 List *l = makeNode(List);
285 lfirst(l) = this_value;
288 lnext(l) = nodeRead(false);
294 return_value = (Node *) l;
298 return_value = this_value;
300 return (return_value);