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c592202345
* examples/c/calc/calc.y: Restore to its original state, with parse.error=detailed instead of parse.error=custom (this example should be simple). * examples/c/calc/calc.test: Check syntax errors. * examples/c/lexcalc/parse.y: Add comments.
90 lines
2.1 KiB
C
90 lines
2.1 KiB
C
/* Prologue (directives). -*- C -*- */
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/* Disable Flex features we don't need, to avoid warnings. */
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%option nodefault noinput nounput noyywrap
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%option reentrant
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%{
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#include <assert.h>
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#include <limits.h> /* INT_MIN */
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#include <stdlib.h> /* strtol */
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#include "parse.h"
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%}
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%x SC_STRING
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%%
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%{
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// Number of opened parentheses.
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int nesting = 0;
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// A buffer storing the text inside the outer parentheses.
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char *str = NULL;
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// Its allocated size.
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int capacity = 0;
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// Its used size.
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int size = 0;
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#define STR_APPEND() \
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do { \
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if (capacity < size + yyleng + 1) \
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{ \
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do \
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capacity = capacity ? 2 * capacity : 128; \
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while (capacity < size + yyleng + 1); \
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str = realloc (str, capacity); \
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} \
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memcpy (str + size, yytext, yyleng); \
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size += yyleng; \
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assert (size < capacity); \
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} while (0)
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%}
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// Rules.
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"+" return TOK_PLUS;
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"-" return TOK_MINUS;
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"*" return TOK_STAR;
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"/" return TOK_SLASH;
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"(" nesting += 1; BEGIN SC_STRING;
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/* Scan an integer. */
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[0-9]+ {
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errno = 0;
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long n = strtol (yytext, NULL, 10);
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if (! (INT_MIN <= n && n <= INT_MAX && errno != ERANGE))
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yyerror (yyscanner, res, "integer is out of range");
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yylval->TOK_NUM = (int) n;
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return TOK_NUM;
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}
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/* Ignore white spaces. */
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[ \t]+ continue;
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"\n" return TOK_EOL;
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. yyerror (yyscanner, res, "syntax error, invalid character: %c", yytext[0]);
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<SC_STRING>
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{
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"("+ nesting += yyleng; STR_APPEND ();
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")" {
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if (!--nesting)
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{
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BEGIN INITIAL;
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if (str)
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str[size] = 0;
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yylval->TOK_STR = str;
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return TOK_STR;
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}
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else
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STR_APPEND ();
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}
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[^()]+ STR_APPEND ();
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}
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<<EOF>> return TOK_EOF;
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%%
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/* Epilogue (C code). */
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