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Suggested by Askar Safin. http://lists.gnu.org/archive/html/bug-bison/2018-12/msg00003.html * examples/c/lexcalc/Makefile, examples/c/lexcalc/README.md, * examples/c/lexcalc/lexcalc.test, examples/c/lexcalc/local.mk, * examples/c/lexcalc/parse.y, examples/c/lexcalc/scan.l: New.
44 lines
860 B
C++
44 lines
860 B
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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%{
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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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%%
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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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"(" return TOK_LPAREN;
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")" return TOK_RPAREN;
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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 (nerrs, "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 (nerrs, "syntax error, invalid character");
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<<EOF>> return TOK_EOF;
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%%
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/* Epilogue (C code). */
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