Sync eclasses from Emacs overlay (revision 1542).

elisp-common.eclass:
Remove dead function elisp-comp; it has	been deprecated more than two
years ago in bug 235442.
New function elisp-need-emacs, tests if the eselected Emacs version is
at least the major version specified as argument.

elisp.eclass:
Use function elisp-need-emacs in elisp_pkg_setup.

1 files changed, 33 insertions, 10 deletions

diff --git a/eclass/elisp-common.eclass b/eclass/elisp-common.eclass
index 9e530f3375af..8c73a3acf4da 100644
--- a/eclass/elisp-common.eclass
+++ b/eclass/elisp-common.eclass
@@ -1,6 +1,6 @@
 # Copyright 1999-2010 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
-# $Header: /var/cvsroot/gentoo-x86/eclass/elisp-common.eclass,v 1.68 2010/10/09 15:30:43 ulm Exp $
+# $Header: /var/cvsroot/gentoo-x86/eclass/elisp-common.eclass,v 1.69 2010/11/23 20:56:08 ulm Exp $
 #
 # Copyright 2002-2004 Matthew Kennedy <mkennedy@gentoo.org>
 # Copyright 2003      Jeremy Maitin-Shepard <jbms@attbi.com>
@@ -29,6 +29,19 @@
 # to your DEPEND/RDEPEND line and use the functions provided here to
 # bring the files to the correct locations.
 #
+# If your package requires a minimum Emacs version, e.g. Emacs 23, then
+# the dependency should be on >=virtual/emacs-23 instead.  Because the
+# user can select the Emacs executable with eselect, you should also
+# make sure that the active Emacs version is sufficient.  This can be
+# tested with function elisp-need-emacs(), which would typically be
+# called from pkg_setup(), as in the following example:
+#
+#   	elisp-need-emacs 23 || die "Emacs version too low"
+#
+# Please note that such tests should be limited to packages that are
+# known to fail with lower Emacs versions; the standard case is to
+# depend on virtual/emacs without version.
+#
 # .SS
 # src_compile() usage:
 #
@@ -126,11 +139,6 @@
 # the emacs USE flag is taken from the package database and not from the
 # environment, so it is no problem when you unset USE=emacs between
 # merge and unmerge of a package.
-#
-# .SS
-# Miscellaneous functions:
-#
-# elisp-emacs-version() outputs the version of the currently active Emacs.
 
 # @ECLASS-VARIABLE: SITELISP
 # @DESCRIPTION:
@@ -177,10 +185,6 @@ elisp-compile() {
 	eend $? "elisp-compile: batch-byte-compile failed"
 }
 
-elisp-comp() {
-	die "Function elisp-comp is not supported any more, see bug 235442"
-}
-
 # @FUNCTION: elisp-emacs-version
 # @DESCRIPTION:
 # Output version of currently active Emacs.
@@ -192,6 +196,25 @@ elisp-emacs-version() {
 	rm -f "${T}"/emacs-version.el
 }
 
+# @FUNCTION: elisp-need-emacs
+# @USAGE: <version>
+# @RETURN: 0 if true, 1 otherwise
+# @DESCRIPTION:
+# Test if the eselected Emacs version is at least the major version
+# specified as argument.
+
+elisp-need-emacs() {
+	local need_emacs=$1
+	local have_emacs=$(elisp-emacs-version)
+	einfo "Emacs version: ${have_emacs}"
+	if ! [[ ${have_emacs%%.*} -ge ${need_emacs%%.*} ]]; then
+		eerror "This package needs at least Emacs ${need_emacs%%.*}."
+		eerror "Use \"eselect emacs\" to select the active version."
+		return 1
+	fi
+	return 0
+}
+
 # @FUNCTION: elisp-make-autoload-file
 # @USAGE: [output file] [list of directories]
 # @DESCRIPTION: