gnu: doc: Allow documentation to be translated.

* po/doc/contributing.pot: New file.
* po/doc/guix.pot: New file.
* po/doc/local.mk: New file.
* Makefile.am: Include it. Add gettext command. Add silent rules for po4a.
* configure.ac: Look for po4a-translate and po4a-updatepo.
* doc/local.mk: Add rules to generate translated texi files.
(TRANSLATED_INFO): New variable.
(BUILT_SOURCES, EXTRA_DIST, MAINTAINERCLEANFILES): Add it.
* .gitignore: Add generated files.

.gitignore

@@ -28,6 +28,21 @@
 /configure
 /doc/*.1
 /doc/.dirstamp
+/doc/guix.*.aux
+/doc/guix.*.cp
+/doc/guix.*.cps
+/doc/guix.*.fn
+/doc/guix.*.fns
+/doc/guix.*.html
+/doc/guix.*.info
+/doc/guix.*.info-[0-9]
+/doc/guix.*.ky
+/doc/guix.*.pg
+/doc/guix.*.toc
+/doc/guix.*.t2p
+/doc/guix.*.tp
+/doc/guix.*.vr
+/doc/guix.*.vrs
 /doc/guix.aux
 /doc/guix.cp
 /doc/guix.cps
@@ -47,6 +62,7 @@
 /doc/os-config-desktop.texi
 /doc/stamp-vti
 /doc/version.texi
+/doc/version-*.texi
 /etc/guix-daemon.cil
 /etc/guix-daemon.conf
 /etc/guix-daemon.service
@@ -79,6 +95,7 @@
 /nix/scripts/list-runtime-roots
 /nix/scripts/offload
 /nix/scripts/substitute
+/po/doc/*.mo
 /po/guix/*.gmo
 /po/guix/*.insert-header
 /po/guix/*.mo

Makefile.am

@@ -10,6 +10,7 @@
 # Copyright © 2017 Jan Nieuwenhuizen <janneke@gnu.org>
 # Copyright © 2017 Arun Isaac <arunisaac@systemreboot.net>
 # Copyright © 2018 Nils Gillmann <ng0@n0.is>
+# Copyright © 2018 Julien Lepiller <julien@lepiller.eu>
 #
 # This file is part of GNU Guix.
 #
@@ -26,6 +27,8 @@
 # You should have received a copy of the GNU General Public License
 # along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+MSGMERGE_UPDATE = @MSGMERGE@ --update
+
 bin_SCRIPTS = scripts/guix
 
 # Handle substitution of fully-expanded Autoconf variables.
@@ -51,6 +54,7 @@ MODULES_NOT_COMPILED =				\
   guix/man-db.scm
 
 include gnu/local.mk
+include po/doc/local.mk
 
 MODULES =					\
   guix/base16.scm				\
@@ -454,7 +458,7 @@ dist_fishcompletion_DATA = etc/completion/fish/guix.fish
 # SELinux policy
 dist_selinux_policy_DATA = etc/guix-daemon.cil
 
-EXTRA_DIST =						\
+EXTRA_DIST +=						\
   HACKING						\
   ROADMAP						\
   TODO							\
@@ -792,3 +796,7 @@ AM_V_DOT_0 = @echo "  DOT     " $@;
 AM_V_HELP2MAN = $(AM_V_HELP2MAN_$(V))
 AM_V_HELP2MAN_ = $(AM_V_HELP2MAN_$(AM_DEFAULT_VERBOSITY))
 AM_V_HELP2MAN_0 = @echo "  HELP2MAN" $@;
+
+AM_V_PO4A = $(AM_V_PO4A_$(V))
+AM_V_PO4A_ = $(AM_V_PO4A_$(AM_DEFAULT_VERBOSITY))
+AM_V_PO4A_0 = @echo "  PO4A" $@;

configure.ac

@@ -263,6 +263,10 @@ AM_MISSING_PROG([DOT], [dot])
 dnl Manual pages.
 AM_MISSING_PROG([HELP2MAN], [help2man])
 
+dnl Documentation translation.
+AM_MISSING_PROG([PO4A_TRANSLATE], [po4a-translate])
+AM_MISSING_PROG([PO4A_UPDATEPO], [po4a-updatepo])
+
 dnl Emacs (optional), for 'etc/indent-package.el'.
 AC_PATH_PROG([EMACS], [emacs], [/usr/bin/emacs])
 AC_SUBST([EMACS])

doc/local.mk

@@ -4,6 +4,7 @@
 # Copyright © 2013 Andreas Enge <andreas@enge.fr>
 # Copyright © 2016 Taylan Ulrich Bayırlı/Kammer <taylanbayirli@gmail.com>
 # Copyright © 2016, 2018 Mathieu Lirzin <mthl@gnu.org>
+# Copyright © 2018 Julien Lepiller <julien@lepiller.eu>
 #
 # This file is part of GNU Guix.
 #
@@ -51,10 +52,51 @@ OS_CONFIG_EXAMPLES_TEXI =			\
   %D%/os-config-desktop.texi			\
   %D%/os-config-lightweight-desktop.texi
 
+TRANSLATED_INFO =
+
 # Bundle this file so that makeinfo finds it in out-of-source-tree builds.
-BUILT_SOURCES        += $(OS_CONFIG_EXAMPLES_TEXI)
-EXTRA_DIST           += $(OS_CONFIG_EXAMPLES_TEXI)
-MAINTAINERCLEANFILES  = $(OS_CONFIG_EXAMPLES_TEXI)
+BUILT_SOURCES        += $(OS_CONFIG_EXAMPLES_TEXI) $(TRANSLATED_INFO)
+EXTRA_DIST           += $(OS_CONFIG_EXAMPLES_TEXI) $(TRANSLATED_INFO)
+MAINTAINERCLEANFILES  = $(OS_CONFIG_EXAMPLES_TEXI) $(TRANSLATED_INFO)
+
+PO4A_PARAMS := -M UTF-8 -L UTF-8 #master and localized encoding
+PO4A_PARAMS += -k 0 # produce an output even if the translation is not complete
+PO4A_PARAMS += -f texinfo # texinfo format
+
+# When a change to guix.texi occurs, it is not translated immediately.
+# Because @pxref and @xref commands are reference to a section by name, they
+# should be translated. If a modification adds a reference to a section, this
+# reference is not translated, which means it references a section that does not
+# exist.
+# This command loops through the translated files looking for references. For
+# each of these references, it tries to find the translation and replaces the
+# reference name, even in untranslated strings.
+# The last sed is a multiline sed because some references span multiple lines.
+define xref_command
+cat "$@.tmp" | egrep '@p?x?ref' -A1 | sed 'N;s|--\n||g;P;D' | sed 's|^| |g' | \
+        tr -d '\012' | sed 's|\(@p\?x\?ref\)|\n\1|g' | egrep '@p?x?ref' | \
+        sed 's|^.*@p\?x\?ref{\([^,}]*\).*$$|\1|g' | sort | uniq | while read e; do \
+  line=$$(grep -n "^msgid \"$$e\"" "$<" | cut -f1 --delimiter=":") ;\
+  ((line++)) ;\
+  if [ "$$line" != "1" ]; then \
+    translation=$$(head -n $$line "$<" | tail -1 | grep msgstr | sed 's|msgstr "\(.*\)"|\1|') ;\
+    if [ "$$translation" != "" ]; then \
+	  sed "N;s@\(p\?x\?ref\){$$(echo $$e | sed 's| |[\\n ]|g')\(,\|}\)@\1{$$translation\2@g;P;D" -i "$@.tmp" ;\
+    fi ;\
+  fi ;\
+done
+endef
+
+$(srcdir)/%D%/guix.%.texi: po/doc/guix.%.po $(srcdir)/%D%/contributing.%.texi
+	-$(AM_V_PO4A)$(PO4A_TRANSLATE) $(PO4A_PARAMS) -m "%D%/guix.texi" -p "$<" -l "$@.tmp"
+	-sed -i "s|guix\.info|$$(basename "$@" | sed 's|texi$$|info|')|" "$@.tmp"
+	-$(xref_command)
+	-mv "$@.tmp" "$@"
+
+$(srcdir)/%D%/contributing.%.texi: po/doc/guix.%.po po/doc/contributing.%.po
+	-$(AM_V_PO4A)$(PO4A_TRANSLATE) $(PO4A_PARAMS) -m "%D%/contributing.texi" -p "$(word 2,$^)" -l "$@.tmp"
+	-$(xref_command)
+	-mv "$@.tmp" "$@"
 
 %D%/os-config-%.texi: gnu/system/examples/%.tmpl
 	$(AM_V_GEN)$(MKDIR_P) "`dirname $@`";	\

po/doc/local.mk

+# GNU Guix --- Functional package management for GNU
+# Copyright © 2018 Julien Lepiller <julien@lepiller.eu>
+#
+# This file is part of GNU Guix.
+#
+# GNU Guix is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or (at
+# your option) any later version.
+#
+# GNU Guix is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+EXTRA_DIST =
+
+POT_OPTIONS = --package-name "guix" --package-version "$(VERSION)" \
+	          --copyright-holder "Ludovic Courtès" \
+			  --msgid-bugs-address "ludo@gnu.org"
+
+$(srcdir)/po/doc/guix.%.po: $(srcdir)/po/doc/guix.pot
+	@lang=`echo $$(basename "$@") | sed -e 's|^guix.||' -e 's|.po$$||'` ;\
+	if test -f "$@"; then \
+	  test "$(srcdir)" = . && cdcmd="" || cdcmd="cd $(srcdir) && "; \
+	  echo "$${cdcmd}$(MSGMERGE_UPDATE) $(MSGMERGE_OPTIONS) --lang=$${lang} $@ $<"; \
+	  cd $(srcdir) \
+	    && { case `$(MSGMERGE_UPDATE) --version | sed 1q | sed -e 's,^[^0-9]*,,'` in \
+	        '' | 0.[0-9] | 0.[0-9].* | 0.1[0-7] | 0.1[0-7].*) \
+	          $(MSGMERGE_UPDATE) $(MSGMERGE_OPTIONS) $@ $<;; \
+	        *) \
+	          $(MSGMERGE_UPDATE) $(MSGMERGE_OPTIONS) --lang=$${lang} $@ $<;; \
+	      esac; \
+	    }; \
+	  touch "$@"; \
+	else \
+	     echo "File $@ does not exist. If you are a translator, you can create it through 'msginit'." 1>&2; \
+	     exit 1; \
+	fi
+
+$(srcdir)/po/doc/contributing.%.po: $(srcdir)/po/doc/contributing.pot
+	@lang=`echo $$(basename "$@") | sed -e 's|^contributing.||' -e 's|.po$$||'` ;\
+	if test -f "$@"; then \
+	  test "$(srcdir)" = . && cdcmd="" || cdcmd="cd $(srcdir) && "; \
+	  echo "$${cdcmd}$(MSGMERGE_UPDATE) $(MSGMERGE_OPTIONS) --lang=$${lang} $@ $<"; \
+	  cd $(srcdir) \
+	    && { case `$(MSGMERGE_UPDATE) --version | sed 1q | sed -e 's,^[^0-9]*,,'` in \
+	        '' | 0.[0-9] | 0.[0-9].* | 0.1[0-7] | 0.1[0-7].*) \
+	          $(MSGMERGE_UPDATE) $(MSGMERGE_OPTIONS) $@ $<;; \
+	        *) \
+	          $(MSGMERGE_UPDATE) $(MSGMERGE_OPTIONS) --lang=$${lang} $@ $<;; \
+	      esac; \
+	    }; \
+	  touch "$@"; \
+	else \
+	     echo "File $@ does not exist. If you are a translator, you can create it through 'msginit'." 1>&2; \
+	     exit 1; \
+	fi
+
+$(srcdir)/po/doc/contributing.pot-update: doc/contributing.texi
+	$(AM_V_PO4A)$(PO4A_UPDATEPO) -M UTF-8 -f texinfo -m "$<" \
+		-p "$$(echo $@ | sed 's|-update||')" $(POT_OPTIONS)
+	@touch "$$(echo $@ | sed 's|-update||')"
+
+$(srcdir)/po/doc/guix.pot-update: doc/guix.texi
+	$(AM_V_PO4A)$(PO4A_UPDATEPO) -M UTF-8 -f texinfo -m "$<" \
+		-p "$$(echo $@ | sed 's|-update||')" $(POT_OPTIONS)
+	@touch "$$(echo $@ | sed 's|-update||')"
+
+doc-pot-update:
+	$(MAKE) $(srcdir)/po/doc/guix.pot-update
+	$(MAKE) $(srcdir)/po/doc/contributing.pot-update