1# flex.m4 serial 2
2# Copyright (C) 2012-2015, 2018-2021 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[].
11AN_MAKEVAR([LEX],  [AC_PROG_LEX])
12AN_PROGRAM([lex],  [AC_PROG_LEX])
13AN_PROGRAM([flex], [AC_PROG_LEX])
14AC_DEFUN_ONCE([AC_PROG_LEX],
15[AC_CHECK_PROGS([LEX], [flex lex], [:])
16if test "x$LEX" != "x:"; then
17  _AC_PROG_LEX_YYTEXT_DECL
18fi
19AC_SUBST([LEX_IS_FLEX],
20         [`test "$ac_cv_prog_lex_is_flex" = yes && echo true || echo false`])dnl
21])
22
23
24# _AC_PROG_LEX_YYTEXT_DECL
25# ------------------------
26# Check whether this is Flex, for the Lex output root, the Lex library,
27# and whether Lex declares yytext as a char * by default.
28m4_define([_AC_PROG_LEX_YYTEXT_DECL],
29[AC_CACHE_CHECK([whether lex is flex],
30                [ac_cv_prog_lex_is_flex],
31[cat >conftest.l <<_ACEOF[
32%option debug nodefault noinput nounput noyywrap never-interactive
33%x SC_CONF_TEST
34%%
35a { BEGIN SC_CONF_TEST; }
36]_ACEOF
37if _AC_DO_VAR([LEX conftest.l]); then
38  ac_cv_prog_lex_is_flex=yes
39else
40  ac_cv_prog_lex_is_flex=no
41fi
42])
43
44
45AC_CACHE_CHECK([whether flex supports --header=FILE],
46                [ac_cv_prog_lex_supports_header_opt],
47[if _AC_DO_VAR([LEX --header=conftest.h conftest.l]); then
48  ac_cv_prog_lex_supports_header_opt=yes
49else
50  ac_cv_prog_lex_supports_header_opt=no
51fi
52])
53if test "$ac_cv_prog_lex_supports_header_opt" = yes; then
54  FLEX_SUPPORTS_HEADER_OPT=true
55else
56  FLEX_SUPPORTS_HEADER_OPT=false
57fi
58
59
60cat >conftest.l <<_ACEOF[
61%%
62a { ECHO; }
63b { REJECT; }
64c { yymore (); }
65d { yyless (1); }
66e { /* IRIX 6.5 flex 2.5.4 underquotes its yyless argument.  */
67    yyless ((input () != 0)); }
68f { unput (yytext[0]); }
69. { BEGIN INITIAL; }
70%%
71#ifdef YYTEXT_POINTER
72extern char *yytext;
73#endif
74int
75main (void)
76{
77  return ! yylex () + ! yywrap ();
78}
79]_ACEOF
80_AC_DO_VAR([LEX conftest.l])
81AC_CACHE_CHECK([lex output file root], [ac_cv_prog_lex_root], [
82if test -f lex.yy.c; then
83  ac_cv_prog_lex_root=lex.yy
84elif test -f lexyy.c; then
85  ac_cv_prog_lex_root=lexyy
86else
87  AC_MSG_ERROR([cannot find output from $LEX; giving up])
88fi])
89AC_SUBST([LEX_OUTPUT_ROOT], [$ac_cv_prog_lex_root])dnl
90
91if test -z "${LEXLIB+set}"; then
92  AC_CACHE_CHECK([lex library], [ac_cv_lib_lex], [
93    ac_save_LIBS=$LIBS
94    ac_cv_lib_lex='none needed'
95    for ac_lib in '' -lfl -ll; do
96      LIBS="$ac_lib $ac_save_LIBS"
97      AC_LINK_IFELSE([AC_LANG_DEFINES_PROVIDED[`cat $LEX_OUTPUT_ROOT.c`]],
98        [ac_cv_lib_lex=$ac_lib])
99      test "$ac_cv_lib_lex" != 'none needed' && break
100    done
101    LIBS=$ac_save_LIBS
102  ])
103  test "$ac_cv_lib_lex" != 'none needed' && LEXLIB=$ac_cv_lib_lex
104fi
105AC_SUBST([LEXLIB])
106
107AC_CACHE_CHECK([whether yytext is a pointer],
108               [ac_cv_prog_lex_yytext_pointer],
109[# POSIX says lex can declare yytext either as a pointer or an array; the
110# default is implementation-dependent.  Figure out which it is, since
111# not all implementations provide the %pointer and %array declarations.
112ac_cv_prog_lex_yytext_pointer=no
113ac_save_LIBS=$LIBS
114LIBS="$LEXLIB $ac_save_LIBS"
115AC_LINK_IFELSE([AC_LANG_DEFINES_PROVIDED
116  [#define YYTEXT_POINTER 1
117`cat $LEX_OUTPUT_ROOT.c`]],
118  [ac_cv_prog_lex_yytext_pointer=yes])
119LIBS=$ac_save_LIBS
120])
121dnl
122if test $ac_cv_prog_lex_yytext_pointer = yes; then
123  AC_DEFINE([YYTEXT_POINTER], [1],
124            [Define to 1 if `lex' declares `yytext' as a `char *' by default,
125             not a `char[]'.])
126fi
127rm -f conftest.l $LEX_OUTPUT_ROOT.c
128])# _AC_PROG_LEX_YYTEXT_DECL
129