m4/flex.m4

   1 # flex.m4 serial 2
   2 # Copyright (C) 2012 Free Software Foundation, Inc.
   3 # This file is free software; the Free Software Foundation
   4 # gives unlimited permission to copy and/or distribute it,
   5 # with or without modifications, as long as this notice is preserved.
   6
   7 # AC_PROG_LEX
   8 # -----------
   9 # Look for flex or lex.  Set its associated library to LEXLIB.
  10 # Check if lex declares yytext as a char * by default, not a char[].
  11 AN_MAKEVAR([LEX],  [AC_PROG_LEX])
  12 AN_PROGRAM([lex],  [AC_PROG_LEX])
  13 AN_PROGRAM([flex], [AC_PROG_LEX])
  14 AC_DEFUN_ONCE([AC_PROG_LEX],
  15 [AC_CHECK_PROGS([LEX], [flex lex], [:])
  16 if test "x$LEX" != "x:"; then
  17   _AC_PROG_LEX_YYTEXT_DECL
  18 fi])
  19
  20
  21 # _AC_PROG_LEX_YYTEXT_DECL
  22 # ------------------------
  23 # Check whether this is Flex, for the Lex output root, the Lex library,
  24 # and whether Lex declares yytext as a char * by default.
  25 m4_define([_AC_PROG_LEX_YYTEXT_DECL],
  26 [AC_CACHE_CHECK([whether lex is flex],
  27                 [ac_cv_prog_lex_is_flex],
  28 [cat >conftest.l <<_ACEOF[
  29 %option debug nodefault noinput nounput noyywrap never-interactive
  30 %x SC_CONF_TEST
  31 %%
  32 a { BEGIN SC_CONF_TEST; }
  33 ]_ACEOF
  34 if _AC_DO_VAR([LEX conftest.l]); then
  35   ac_cv_prog_lex_is_flex=yes
  36 else
  37   ac_cv_prog_lex_is_flex=no
  38 fi
  39 ])
  40 AC_SUBST([LEX_IS_FLEX],
  41          [`test "$ac_cv_prog_lex_is_flex" = yes && echo true || echo false`])dnl
  42
  43 cat >conftest.l <<_ACEOF[
  44 %%
  45 a { ECHO; }
  46 b { REJECT; }
  47 c { yymore (); }
  48 d { yyless (1); }
  49 e { /* IRIX 6.5 flex 2.5.4 underquotes its yyless argument.  */
  50     yyless ((input () != 0)); }
  51 f { unput (yytext[0]); }
  52 . { BEGIN INITIAL; }
  53 %%
  54 #ifdef YYTEXT_POINTER
  55 extern char *yytext;
  56 #endif
  57 int
  58 main (void)
  59 {
  60   return ! yylex () + ! yywrap ();
  61 }
  62 ]_ACEOF
  63 _AC_DO_VAR([LEX conftest.l])
  64 AC_CACHE_CHECK([lex output file root], [ac_cv_prog_lex_root], [
  65 if test -f lex.yy.c; then
  66   ac_cv_prog_lex_root=lex.yy
  67 elif test -f lexyy.c; then
  68   ac_cv_prog_lex_root=lexyy
  69 else
  70   AC_MSG_ERROR([cannot find output from $LEX; giving up])
  71 fi])
  72 AC_SUBST([LEX_OUTPUT_ROOT], [$ac_cv_prog_lex_root])dnl
  73
  74 if test -z "${LEXLIB+set}"; then
  75   AC_CACHE_CHECK([lex library], [ac_cv_lib_lex], [
  76     ac_save_LIBS=$LIBS
  77     ac_cv_lib_lex='none needed'
  78     for ac_lib in '' -lfl -ll; do
  79       LIBS="$ac_lib $ac_save_LIBS"
  80       AC_LINK_IFELSE([AC_LANG_DEFINES_PROVIDED[`cat $LEX_OUTPUT_ROOT.c`]],
  81         [ac_cv_lib_lex=$ac_lib])
  82       test "$ac_cv_lib_lex" != 'none needed' && break
  83     done
  84     LIBS=$ac_save_LIBS
  85   ])
  86   test "$ac_cv_lib_lex" != 'none needed' && LEXLIB=$ac_cv_lib_lex
  87 fi
  88 AC_SUBST([LEXLIB])
  89
  90 AC_CACHE_CHECK([whether yytext is a pointer],
  91                [ac_cv_prog_lex_yytext_pointer],
  92 [# POSIX says lex can declare yytext either as a pointer or an array; the
  93 # default is implementation-dependent.  Figure out which it is, since
  94 # not all implementations provide the %pointer and %array declarations.
  95 ac_cv_prog_lex_yytext_pointer=no
  96 ac_save_LIBS=$LIBS
  97 LIBS="$LEXLIB $ac_save_LIBS"
  98 AC_LINK_IFELSE([AC_LANG_DEFINES_PROVIDED
  99   [#define YYTEXT_POINTER 1
 100 `cat $LEX_OUTPUT_ROOT.c`]],
 101   [ac_cv_prog_lex_yytext_pointer=yes])
 102 LIBS=$ac_save_LIBS
 103 ])
 104 dnl
 105 if test $ac_cv_prog_lex_yytext_pointer = yes; then
 106   AC_DEFINE([YYTEXT_POINTER], [1],
 107             [Define to 1 if `lex' declares `yytext' as a `char *' by default,
 108              not a `char[]'.])
 109 fi
 110 rm -f conftest.l $LEX_OUTPUT_ROOT.c
 111 ])# _AC_PROG_LEX_YYTEXT_DECL