Re: 1.5 automatically generating C++, F77 tags

[Albert Chin]

On Tue, Jun 03, 2003 at 08:56:38AM -0500, Bob Friesenhahn wrote:
> On Tue, 3 Jun 2003, Alexandre Duret-Lutz wrote:
> 
> > >>> "Albert" == Albert Chin <address@hidden> writes:
> >
> > [...]
> >
> >  Albert> I don't have a problem requiring AC_PROG_CXX, AC_PROG_F77, or
> >  Albert> AM_PROG_GCJ before AC_PROG_LIBTOOL. Anyone see this as a problem?
> >
> > As a user I wouldn't care about this little inconvenience if it
> > allows Libtool not to bloat my configure with useless checks.
> >
> > However, requiring this will break thousands of configure.ac.  I
> > expect most of them to run AC_INIT, AM_INIT_AUTOMAKE,
> > AC_PROG_LIBTOOL early, and then go on with other checks such as
> > language checks.
> 
> This is true.  It may be very inconvenient for some packages to change
> the ordering.
> 
> > Maybe this could be changed as follows:
> 
> It is generally not a good approach to base a design on side-effects
> or assumptions.  Up to now, adding AC_PROG_LIBTOOL to a configure.ac
> file has been sufficient to configure libtool, regardless of whether
> libtool is stand-alone or embedded.  This behavior should not be
> altered.
> 
> I believe that a much better solution is to add a AC_LIBTOOL_TAGS (or
> AC_LIBTOOL_LANGUAGES) macro which can be used like
> 
> AC_LIBTOOL_TAGS([c c++])
> AC_PROG_LIBTOOL
>
> [ snip snip ]

Ok, just whipped this up as a proof of concept. Haven't really tested.
Am I headed in the right direction.

-- 
albert chin (address@hidden)

-- snip snip
--- libtool.m4.orig     2003-06-01 16:07:41.276467000 -0500
+++ libtool.m4  2003-06-03 10:22:57.667598339 -0500
@@ -39,35 +39,9 @@
 # ---------------
 AC_DEFUN([AC_PROG_LIBTOOL],
 [AC_REQUIRE([_AC_PROG_LIBTOOL])dnl
-dnl If AC_PROG_CXX has already been expanded, run AC_LIBTOOL_CXX
-dnl immediately, otherwise, hook it in at the end of AC_PROG_CXX.
-  AC_PROVIDE_IFELSE([AC_PROG_CXX],
-    [AC_LIBTOOL_CXX],
-    [define([AC_PROG_CXX], defn([AC_PROG_CXX])[AC_LIBTOOL_CXX
-  ])])
-dnl And a similar setup for Fortran 77 support
-  AC_PROVIDE_IFELSE([AC_PROG_F77],
-    [AC_LIBTOOL_F77],
-    [define([AC_PROG_F77], defn([AC_PROG_F77])[AC_LIBTOOL_F77
-])])
-
-dnl Quote A][M_PROG_GCJ so that aclocal doesn't bring it in needlessly.
-dnl If either AC_PROG_GCJ or A][M_PROG_GCJ have already been expanded, run
-dnl AC_LIBTOOL_GCJ immediately, otherwise, hook it in at the end of both.
-  AC_PROVIDE_IFELSE([AC_PROG_GCJ],
-    [AC_LIBTOOL_GCJ],
-    [AC_PROVIDE_IFELSE([A][M_PROG_GCJ],
-      [AC_LIBTOOL_GCJ],
-      [AC_PROVIDE_IFELSE([LT_AC_PROG_GCJ],
-       [AC_LIBTOOL_GCJ],
-      [ifdef([AC_PROG_GCJ],
-            [define([AC_PROG_GCJ], defn([AC_PROG_GCJ])[AC_LIBTOOL_GCJ])])
-       ifdef([A][M_PROG_GCJ],
-            [define([A][M_PROG_GCJ], defn([A][M_PROG_GCJ])[AC_LIBTOOL_GCJ])])
-       ifdef([LT_AC_PROG_GCJ],
-            [define([LT_AC_PROG_GCJ],
-               defn([LT_AC_PROG_GCJ])[AC_LIBTOOL_GCJ])])])])
-])])# AC_PROG_LIBTOOL
+AC_PROVIDE_IFELSE([AC_LIBTOOL_TAGS],,
+  [AC_LIBTOOL_TAGS([C C++ F77])])
+]) # AC_PROG_LIBTOOL
 
 
 # _AC_PROG_LIBTOOL
@@ -1608,15 +1581,26 @@
 ])# AC_LIBTOOL_SYS_DYNAMIC_LINKER
 
 
+# AC_LIBTOOL_TAGS
+# ---------------
+# tags to enable
+AC_DEFUN([AC_LIBTOOL_TAGS],
+[m4_define([_LT_TAGS],[$1])
+]) # AC_LIBTOOL_TAGS
+
+# _LT_AC_CHECK_TAG
+# ----------------
+AC_DEFUN([_LT_AC_CHECK_TAG],
+[if grep "^# ### BEGIN LIBTOOL TAG CONFIG: $1$" < "${ofile}" > /dev/null
+then
+    AC_MSG_ERROR([tag name \"$1\" already exists])
+fi
+]) # _LT_AC_CHECK_TAG
+
 # _LT_AC_TAGCONFIG
 # ----------------
 AC_DEFUN([_LT_AC_TAGCONFIG],
-[AC_ARG_WITH([tags],
-    [AC_HELP_STRING([--with-tags@<:@=TAGS@:>@],
-        [include additional configurations @<:@automatic@:>@])],
-    [tagnames="$withval"])
-
-if test -f "$ltmain" && test -n "$tagnames"; then
+[if test -f "$ltmain" && test -n "_LT_TAGS"; then
   if test ! -f "${ofile}"; then
     AC_MSG_WARN([output file `$ofile' does not exist])
   fi
@@ -1634,66 +1618,37 @@
   # Note that this assumes the entire list is on one line.
   available_tags=`grep "^available_tags=" "${ofile}" | $SED -e 
's/available_tags=\(.*$\)/\1/' -e 's/\"//g'`
 
-  lt_save_ifs="$IFS"; IFS="${IFS}$PATH_SEPARATOR,"
-  for tagname in $tagnames; do
-    IFS="$lt_save_ifs"
-    # Check whether tagname contains only valid characters
-    case `$echo "X$tagname" | $Xsed -e 
's:[[-_ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890,/]]::g'` 
in
-    "") ;;
-    *)  AC_MSG_ERROR([invalid tag name: $tagname])
-       ;;
-    esac
-
-    if grep "^# ### BEGIN LIBTOOL TAG CONFIG: $tagname$" < "${ofile}" > 
/dev/null
-    then
-      AC_MSG_ERROR([tag name \"$tagname\" already exists])
-    fi
-
-    # Update the list of available tags.
-    if test -n "$tagname"; then
-      echo appending configuration tag \"$tagname\" to $ofile
-
-      case $tagname in
-      CXX)
-       if test -n "$CXX" && test "X$CXX" != "Xno"; then
-         AC_LIBTOOL_LANG_CXX_CONFIG
-       else
-         tagname=""
-       fi
-       ;;
-
-      F77)
-       if test -n "$F77" && test "X$F77" != "Xno"; then
-         AC_LIBTOOL_LANG_F77_CONFIG
-       else
-         tagname=""
-       fi
-       ;;
-
-      GCJ)
-       if test -n "$GCJ" && test "X$GCJ" != "Xno"; then
-         AC_LIBTOOL_LANG_GCJ_CONFIG
-       else
-         tagname=""
-       fi
-       ;;
-
-      RC)
-       AC_LIBTOOL_LANG_RC_CONFIG
-       ;;
-
-      *)
-       AC_MSG_ERROR([Unsupported tag name: $tagname])
-       ;;
-      esac
-
-      # Append the new tag name to the list of available tags.
-      if test -n "$tagname" ; then
-      available_tags="$available_tags $tagname"
-    fi
-    fi
-  done
-  IFS="$lt_save_ifs"
+  AC_FOREACH([_LT_TAG], _LT_TAGS,
+      [m4_if(_LT_TAG, C, ,
+          [m4_if(_LT_TAG, C++, 
+              [_LT_AC_CHECK_TAG([CXX])
+  echo appending configuration tag \"_LT_TAG\" to $ofile
+  if test -n "$CXX" && test "X$CXX" != "Xno"; then
+      AC_LIBTOOL_LANG_CXX_CONFIG
+      available_tags="$available_tags _LT_TAG"
+  fi],
+              [m4_if(_LT_TAG, F77,
+                  [_LT_AC_CHECK_TAG(_LT_TAG)
+  echo appending configuration tag \"_LT_TAG\" to $ofile
+  if test -n "$F77" && test "X$F77" != "Xno"; then
+      AC_LIBTOOL_LANG_F77_CONFIG
+      available_tags="$available_tags _LT_TAG"
+  fi],
+                  [m4_if(_LT_TAG, GCJ,
+                      [_LT_AC_CHECK_TAG(_LT_TAG)
+  echo appending configuration tag \"_LT_TAG\" to $ofile
+  if test -n "$GCJ" && test "X$GCJ" != "Xno"; then
+      AC_LIBTOOL_LANG_GCJ_CONFIG
+      available_tags="$available_tags _LT_TAG"
+  fi],
+                      [m4_if(_LT_TAG, RC,
+                          [_LT_AC_CHECK_TAG(_LT_TAG)
+  echo appending configuration tag \"_LT_TAG\" to $ofile
+  AC_LIBTOOL_LANG_RC_CONFIG
+  available_tags="$available_tags _LT_TAG"
+  fi],
+                          m4_errprintn(m4_location[: error: invalid tag name: 
]"_LT_TAG")
+  )])])])])])
 
   # Now substitute the updated list of available tags.
   if eval "sed -e 's/^available_tags=.*\$/available_tags=\"$available_tags\"/' 
\"$ofile\" > \"${ofile}T\""; then