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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++ source and header files. Note that header files are generated only when the -d Yacc option is used; see below for more information about this flag, and how to specify it. Files with the extension .y will thus be turned into .c sources and .h headers; likewise, .yy will become .cc and .hh, .y++ will become c++ and h++, .yxx will become .cxx and .hxx, and .ypp will become .cpp and .hpp.
Similarly, lex source files can be used to generate C or C++; the extensions .l, .ll, .l++, .lxx, and .lpp are recognized.
You should never explicitly mention the intermediate (C or C++) file
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.ac must
define the variable
YACC. This is most easily done by invoking
AC_PROG_YACC (see Particular Program Checks).
yacc is invoked, it is passed
YFLAGS. The latter is a user variable and the former 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
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.ac
must define the variable
LEX. You can use
to do this (see Particular Program Checks), but using
(see Macros) is recommended.
When lex is invoked, it is passed
LFLAGS. The latter is a user variable and the former is
intended for the Makefile.am author.
AM_MAINTAINER_MODE (see maintainer-mode) is used, the
rebuild rule for distributed Yacc and Lex sources are only used when
maintainer-mode is enabled, or when the files have been erased.
When lex or yacc sources are used,
-i automatically installs an auxiliary program called
ylwrap in your package (see Auxiliary Programs). This
program is used by the build rules to rename the output of these
tools, and makes it possible to include multiple yacc (or
lex) source files in a single directory. (This is necessary
because yacc's output file name is fixed, and a parallel make could
conceivably invoke more than one instance of yacc
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
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.
 Please note that automake recognizes
AM_YFLAGS only if it is not clustered with other
options; for example, it won't be recognized if
-dt, but it will be if
AM_YFLAGS is -d -t or