Automake has somewhat idiosyncratic support for Yacc and Lex.
Automake assumes that the .c file generated by yacc (or
lex) should be named using the basename of the input file. That
is, for a yacc source file foo.y, Automake will cause the
intermediate file to be named foo.c (as opposed to
y.tab.c, which is more traditional).
The extension of a yacc source file is used to determine the extension
of the resulting C or C++ file. Files with the extension
.y will be turned into .c files; likewise, .yy will
become .cc; .y++, c++; and .yxx,
.cxx.
Likewise, lex source files can be used to generate C or
C++; the extensions .l, .ll, .l++, and
.lxx are recognized.
You should never explicitly mention the intermediate (C or
C++) file in any SOURCES variable; only list the source
file.
The intermediate files generated by yacc (or lex) will be
included in any distribution that is made. That way the user doesn't
need to have yacc or lex.
If a yacc source file is seen, then your configure.in must
define the variable YACC. This is most easily done by invoking
the macro AC_PROG_YACC (see Particular Program Checks).
When yacc is invoked, it is passed YFLAGS and
AM_YFLAGS. The former is a user variable and the latter is
intended for the Makefile.am author.
AM_YFLAGS is usually used to pass the -d option to
yacc. Automake knows what this means and will automatically
adjust its rules to update and distribute the header file built by
yacc -d. What Automake cannot guess, though, is where this
header will be used: it is up to you to ensure the header gets built
before it is first used. Typically this is necessary in order for
dependency tracking to work when the header is included by another
file. The common solution is listing the header file in
BUILT_SOURCES (see Sources) as follows.
BUILT_SOURCES = parser.h
AM_YFLAGS = -d
bin_PROGRAMS = foo
foo_SOURCES = ... parser.y ...
If a lex source file is seen, then your configure.in
must define the variable LEX. You can use AC_PROG_LEX
to do this (see Particular Program Checks), but using AM_PROG_LEX macro
(see Macros) is recommended.
When lex is invoked, it is passed LFLAGS and
AM_LFLAGS. The former is a user variable and the latter is
intended for the Makefile.am author.
Automake makes it possible to include multiple yacc (or
lex) source files in a single program. When there is more than
one distinct yacc (or lex) source file in a directory,
Automake uses a small program called ylwrap to run yacc
(or lex) in a subdirectory. This is necessary because yacc's
output filename is fixed, and a parallel make could conceivably invoke
more than one instance of yacc simultaneously. The ylwrap
program is distributed with Automake. It should appear in the directory
specified by AC_CONFIG_AUX_DIR (see Finding `configure' Input), or the current
directory if that macro is not used in configure.in.
For yacc, simply managing locking is insufficient. The output of
yacc always uses the same symbol names internally, so it isn't
possible to link two yacc parsers into the same executable.
We recommend using the following renaming hack used in gdb:
#define yymaxdepth c_maxdepth
#define yyparse c_parse
#define yylex c_lex
#define yyerror c_error
#define yylval c_lval
#define yychar c_char
#define yydebug c_debug
#define yypact c_pact
#define yyr1 c_r1
#define yyr2 c_r2
#define yydef c_def
#define yychk c_chk
#define yypgo c_pgo
#define yyact c_act
#define yyexca c_exca
#define yyerrflag c_errflag
#define yynerrs c_nerrs
#define yyps c_ps
#define yypv c_pv
#define yys c_s
#define yy_yys c_yys
#define yystate c_state
#define yytmp c_tmp
#define yyv c_v
#define yy_yyv c_yyv
#define yyval c_val
#define yylloc c_lloc
#define yyreds c_reds
#define yytoks c_toks
#define yylhs c_yylhs
#define yylen c_yylen
#define yydefred c_yydefred
#define yydgoto c_yydgoto
#define yysindex c_yysindex
#define yyrindex c_yyrindex
#define yygindex c_yygindex
#define yytable c_yytable
#define yycheck c_yycheck
#define yyname c_yyname
#define yyrule c_yyrule
For each define, replace the c_ prefix with whatever you like.
These defines work for bison, byacc, and traditional
yaccs. If you find a parser generator that uses a symbol not
covered here, please report the new name so it can be added to the list.