Files
third_party_mesa3d/src/glsl/glcpp
Kenneth Graunke f20656e944 glcpp: Rework lexer to use a SKIP state rather than REJECT.
Previously, the rule deleted by this commit was matched every single
time (being the longest match).  If not skipping, it used REJECT to
continue on to the actual correct rule.

The flex manual advises against using REJECT where possible, as it is
one of the most expensive lexer features.  So using it on every match
seems undesirable. Perhaps more importantly, it made it necessary for
the #if directive rules to contain a look-ahead pattern to make them
as long as the (now deleted) "skip the whole line" rule.

This patch introduces an exclusive start state, SKIP, to avoid REJECTs.
Each time the lexer is called, the code at the top of the rules section
will run, implicitly switching the state to the correct one.

Fixes piglit tests 16384-consecutive-chars.frag and
16385-consecutive-chars.frag.
2011-03-03 10:42:37 -08:00
..

glcpp -- GLSL "C" preprocessor

This is a simple preprocessor designed to provide the preprocessing
needs of the GLSL language. The requirements for this preprocessor are
specified in the GLSL 1.30 specification availble from:

http://www.opengl.org/registry/doc/GLSLangSpec.Full.1.30.10.pdf

This specification is not precise on some semantics, (for example,
#define and #if), defining these merely "as is standard for C++
preprocessors". To fill in these details, I've been using a draft of
the C99 standard as available from:

http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf

Any downstream compiler accepting output from glcpp should be prepared
to encounter and deal with the following preprocessor macros:

	#line
	#pragma
	#extension

All other macros will be handles according to the GLSL specification
and will not appear in the output.

Known limitations
-----------------
The __LINE__ and __FILE__ macros are not yet supported.

A file that ends with a function-like macro name as the last
non-whitespace token will result in a parse error, (where it should be
passed through as is).