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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.
reccalc - recursive calculator with Flex and Bison
In this example the generated parser is pure and reentrant: it can be used concurrently in different threads, or recursively. As a proof of this reentrancy, expressions in parenthesis are tokenized as strings, and then recursively parsed from the parser:
exp: STR
{
result r = parse_string ($1);
free ($1);
if (r.nerrs)
{
res->nerrs += r.nerrs;
YYERROR;
}
else
$$ = r.value;
}