Re: new module bison-i18n

[Bruno Haible]

Paul Eggert wrote:
> Good idea, thanks.  Two minor points:
> 
> >     if test -n "$BISON_LOCALEDIR"; then
> >       USER_LINGUAS="${LINGUAS-%UNSET%}"
> >       if test -n "$USER_LINGUAS"; then
> 
> What is the significance of the %UNSET% here?  I.e., why is an unset
> LINGUAS treated as nonempty?  Maybe a comment would help?

OK, I'm adding a comment.

> >     if test -n "$YACC"; then
> >       case "$YACC" in
> >         *bison*)
> >           if ($YACC --print-localedir) >/dev/null 2>&1; then
> 
> This doesn't look quite right, since "yacc" is an alias for "bison" on
> some implementations, so "yacc --print-localedir" will work.  For
> example, I've installed Bison 2.3 in my home directory, so:
> 
>    $ yacc -print-localedir
>    /home/eggert/opt/Linux-i686/bison-2.3/share/locale

I didn't handle this case, fearing that a non-Bison yacc would create
undesired files or read from standard input or things like that. But
since you think it's safe, I'm changing it.

> How about something like the following code instead?

> It's a bit shorter and easier for me to read

... whereas I need extra comments in order to understand the intent of
such code.

I did this change, and installed it into gnulib.

Bruno

diff -u -r1.1 bison-i18n.m4
--- bison-i18n.m4       2 Aug 2006 13:33:14 -0000       1.1
+++ bison-i18n.m4       18 Aug 2006 19:30:43 -0000
@@ -1,5 +1,5 @@
-# bison-i18n.m4 serial 1 (bison-2.1)
-dnl Copyright (C) 2005 Free Software Foundation, Inc.
+# bison-i18n.m4 serial 2
+dnl Copyright (C) 2005-2006 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -19,38 +19,27 @@
     exit 1
   fi
   BISON_LOCALEDIR=
+  BISON_USE_NLS=no
   if test "$USE_NLS" = yes; then
+    dnl Determine bison's localedir.
     dnl AC_PROG_YACC sets the YACC variable; other macros set the BISON 
variable.
-    if test -n "$YACC"; then
-      case "$YACC" in
-        *bison*)
-          if ($YACC --print-localedir) >/dev/null 2>&1; then
-            BISON_LOCALEDIR=`$YACC --print-localedir`
-          fi
-          ;;
-      esac
-    else
-      if test -n "$BISON"; then
-        if test "$BISON" != ":"; then
-          if ($BISON --print-localedir) >/dev/null 2>&1; then
-            BISON_LOCALEDIR=`$BISON --print-localedir`
-          fi
-        fi
-      fi
+    dnl But even is YACC is called "yacc", it may be a script that invokes 
bison
+    dnl and accepts the --print-localedir option.
+    dnl YACC's default value is empty; BISON's default value is :.
+    if (${YACC-${BISON-:}} --print-localedir) >/dev/null 2>&1; then
+      BISON_LOCALEDIR=`${YACC-${BISON-:}} --print-localedir`
     fi
     AC_SUBST([BISON_LOCALEDIR])
     if test -n "$BISON_LOCALEDIR"; then
+      dnl There is no need to enable internationalization if the user doesn't
+      dnl want message catalogs.  So look at the language/locale names for
+      dnl which the user wants message catalogs.  This is $LINGUAS.  If unset
+      dnl or empty, he wants all of them.
       USER_LINGUAS="${LINGUAS-%UNSET%}"
       if test -n "$USER_LINGUAS"; then
         BISON_USE_NLS=yes
-      else
-        BISON_USE_NLS=no
       fi
-    else
-      BISON_USE_NLS=no
     fi
-  else
-    BISON_USE_NLS=no
   fi
   if test $BISON_USE_NLS = yes; then
     AC_DEFINE([YYENABLE_NLS], 1,