The existing DECIMAL_INTEGER pattern is the correct thing to use when
looking for a C decimal integer, (that is, a digit-sequence not
starting with 0 which would instead be an octal integer).
But for #line, we really want to accept any digit sequence, (including
"0"), and always interpret it as a decimal constant. So we add a new
DIGITS pattern for this case.
This should fix the compilation failure noted in bug #28138https://bugs.freedesktop.org/show_bug.cgi?id=28138
(Though the generated file will not be updated until the next commit.)
Previously, the YY_USER_ACTION was overwriting the yylloc->source value
in every action, (after that value had been carefully set by the handling
of the #line directive). Instead, we want to initialize it once in
YY_USER_INIT and then not touch it at all in YY_USER_ACTION.
Matching the newline here meant having to do some redundant work here,
(incrementing line number, resetting column number, and returning a
NEWLINE token), that could otherwise simply be left to the existing rule
which matches a newline.
Worse, when the comment rule matches the newline as well, the parser
can lookahead and see a token for something that should actually be skipped.
For example, in a case like this:
#if 0 // comment here
fail
#else
win
#endif
Both fail and win appear in the output, (not that the condition is being
evaluated incorrectly---merely that one token after the comment's newline
was being lexed/parse regardless of the condition).
This commit fixes the above test case, (which is also remarkably similar
to 087-if-comments which now passes).
Calling exit() on a memory failure probably made sense for the
standalone preprocessor, but doesn't seem too appealing as part of
the GL library. Also, we don't use it in the main compiler.
We define the YY_NO_INPUT macro to avoid one needless function being
generated.
for the other needless functions, (yyunput and yy_top_state), we add a
new UNREACHABLE start condition and call these functions from an
action there. This doesn't change functionality at all, (since we
never enter the UNREACHABLE start condition), but makes the compiler
stop complaining about these two functions being defined but not used.
It's really a bug in flex that these functions are generated with neither
a declaration nor the 'static' keyword, but we can at least avoid the
warnings this way.
Previously, if the outer #ifdef/#ifndef evaluated to false, the inner
directive would not be parsed correctly, (the identifier as the subject
of the #ifdef/#ifndef would inadvertently be skipped along with the other
content correctly being skipped).
We fix this by setting the lexing_if state in each case here.
We also add a new test to the test suite to ensure that this case is tested.
