Files
bison/examples/c/lexcalc/scan.l
Akim Demaille 52ce2a008b build: check -Wmissing-prototypes
pstate_clear is lacking a prototype.
Reported by Ryan
https://lists.gnu.org/r/bug-bison/2020-05/msg00101.html

Besides, none of the C examples were compiled with the warning flags.

* configure.ac (warn_c): Add -Wmissing-prototypes.
* data/skeletons/yacc.c (pstate_clear): Make it static.
* examples/local.mk (TEST_CFLAGS): New.
* examples/c/bistromathic/local.mk, examples/c/calc/local.mk,
* examples/c/lexcalc/local.mk, examples/c/mfcalc/local.mk,
* examples/c/pushcalc/local.mk, examples/c/reccalc/local.mk,
* examples/c/rpcalc/local.mk:
Use it.

GCC's warn_unused_result is not silenced by a cast to void, so we have
to "use" scanf's result.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25509
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425

Flex generated code produces too many warnings, including things such
as, with ICC:

    examples/c/lexcalc/scan.c(1088): error #1682: implicit conversion
              of a 64-bit integral type to a smaller integral type (potential portability problem)
    2259                YY_INPUT( (&YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[number_to_move]),
    2260                ^
    2261
    2262

I am tired of trying to fix Flex's output.  The project does not seem
maintained.  We ought to avoid it.  So, for the time being, don't try
to enable warnings with Flex.

* examples/c/bistromathic/parse.y, examples/c/reccalc/scan.l: Fix
warnings.
* doc/bison.texi: Discard scanf's return value to defeat
-Werror=unused-result.
2020-06-01 08:29:53 +02:00

60 lines
1.5 KiB
C

/* Prologue (directives). -*- C -*- */
/* Disable Flex features we don't need, to avoid warnings. */
%option nodefault noinput nounput noyywrap
%{
#include <errno.h> /* errno, ERANGE */
#include <limits.h> /* INT_MIN */
#include <stdlib.h> /* strtol */
#include "parse.h"
// Each time a rule is matched, advance the end cursor/position.
#define YY_USER_ACTION \
yylloc->last_column += (int) yyleng;
// Move the first position onto the last.
#define LOCATION_STEP() \
do { \
yylloc->first_line = yylloc->last_line; \
yylloc->first_column = yylloc->last_column; \
} while (0)
%}
%%
%{
// Each time yylex is called, move the head position to the end one.
LOCATION_STEP ();
%}
/* Rules. */
"+" return TOK_PLUS;
"-" return TOK_MINUS;
"*" return TOK_STAR;
"/" return TOK_SLASH;
"(" return TOK_LPAREN;
")" return TOK_RPAREN;
/* Scan an integer. */
[0-9]+ {
errno = 0;
long n = strtol (yytext, NULL, 10);
if (! (INT_MIN <= n && n <= INT_MAX && errno != ERANGE))
yyerror (yylloc, nerrs, "integer is out of range");
yylval->TOK_NUM = (int) n;
return TOK_NUM;
}
"\n" yylloc->last_line++; yylloc->last_column = 1; return TOK_EOL;
/* Ignore white spaces. */
[ \t]+ LOCATION_STEP (); continue;
. yyerror (yylloc, nerrs, "syntax error, invalid character"); continue;
<<EOF>> return TOK_YYEOF;
%%
/* Epilogue (C code). */