01/01: build: Generate man pages after compiling Guile objects.

[Mathieu Lirzin]

mthl pushed a commit to branch master
in repository guix.

commit 36629097523b0abd89d1b931293150cb9c1f242d
Author: Eric Bavier <address@hidden>
Date:   Wed Jan 27 20:31:04 2016 -0600

    build: Generate man pages after compiling Guile objects.
    
    This reduces compilation time since scripts are not compiled twice.
    When building with 'make -j4' from a clean repository on an Intel
    i5-2540M, compilation time gets from:
    
    real        4m48.708s
    user        17m29.892s
    sys 0m9.596s
    
    down to:
    
    real        2m23.399s
    user        6m48.604s
    sys 0m6.420s
    
    * doc.am (subcommand-manual-target): Delete function.
    (SUBCOMMANDS): Delete variable.
    (sub_command_mans, gen_man): New variables.
    (dist_man1_MANS): Add $(sub_commands_mans).
    (doc/guix-%.1): New target for sub-commands man pages.  It ensures that
    man pages are built only after compiling Guile objects.
    (doc/guix-daemon.1): Use $(gen_man).  Build only if BUILD_DAEMON.
    (doc/guix.1): Use $(gen_man).  Add $(sub_command_mans) prerequisite.
    
    Co-authored-by: Mathieu Lirzin <address@hidden>
---
 doc.am |   93 +++++++++++++++++++++++++++++++++------------------------------
 1 files changed, 49 insertions(+), 44 deletions(-)

diff --git a/doc.am b/doc.am
index 05b42cd..e542161 100644
--- a/doc.am
+++ b/doc.am
@@ -1,7 +1,9 @@
 # GNU Guix --- Functional package management for GNU
+# Copyright © 2016 Eric Bavier <address@hidden>
 # Copyright © 2012, 2013, 2014, 2015, 2016 Ludovic Courtès <address@hidden>
 # Copyright © 2013 Andreas Enge <address@hidden>
 # Copyright © 2016 Taylan Ulrich Bayırlı/Kammer <address@hidden>
+# Copyright © 2016 Mathieu Lirzin <address@hidden>
 #
 # This file is part of GNU Guix.
 #
@@ -91,55 +93,58 @@ ps-local: $(DOT_FILES=%.dot=$(top_srcdir)/%.eps)            
\
          $(top_srcdir)/doc/images/coreutils-size-map.eps
 dvi-local: ps-local
 
-
-# Manual pages.
-
-doc/guix.1: $(SUBCOMMANDS:%=guix/scripts/%.scm)
-       -$(AM_V_HELP2MAN)LANGUAGE= $(top_builddir)/pre-inst-env         \
-         $(HELP2MAN) --output="$@" guix
-
-# Note: Do not depend on 'guix-daemon' since that would trigger a rebuild even
-# for people building from a tarball.
-doc/guix-daemon.1: nix/nix-daemon/guix-daemon.cc
-       -$(AM_V_HELP2MAN)LANGUAGE= $(top_builddir)/pre-inst-env         \
-         $(HELP2MAN) --output="$@" guix-daemon
-
-define subcommand-manual-target
-
-doc/guix-$(1).1: guix/scripts/$(1).scm
-       -$$(AM_V_HELP2MAN)LANGUAGE= $(top_builddir)/pre-inst-env        \
-         $(HELP2MAN) --output="$$@" "guix $(1)"
-
-endef
-
-SUBCOMMANDS :=                                 \
-  archive                                      \
-  build                                                \
-  challenge                                    \
-  download                                     \
-  edit                                         \
-  environment                                  \
-  gc                                           \
-  hash                                         \
-  import                                       \
-  lint                                         \
-  package                                      \
-  publish                                      \
-  pull                                         \
-  refresh                                      \
-  size                                         \
-  system
-
-$(eval $(foreach subcommand,$(SUBCOMMANDS),                    \
-          $(call subcommand-manual-target,$(subcommand))))
+## ----------- ##
+##  Man pages. ##
+## ----------- ##
+
+sub_commands_mans =                            \
+  doc/guix-archive.1                           \
+  doc/guix-build.1                             \
+  doc/guix-challenge.1                         \
+  doc/guix-download.1                          \
+  doc/guix-edit.1                              \
+  doc/guix-environment.1                       \
+  doc/guix-gc.1                                        \
+  doc/guix-hash.1                              \
+  doc/guix-import.1                            \
+  doc/guix-lint.1                              \
+  doc/guix-package.1                           \
+  doc/guix-publish.1                           \
+  doc/guix-pull.1                              \
+  doc/guix-refresh.1                           \
+  doc/guix-size.1                              \
+  doc/guix-system.1
 
 dist_man1_MANS =                               \
   doc/guix.1                                   \
-  $(SUBCOMMANDS:%=doc/guix-%.1)
+  $(sub_commands_mans)
+
+# Man pages are generated using GNU help2man.
+gen_man = LANGUAGE= $(top_builddir)/pre-inst-env $(HELP2MAN)
+
+# Note: Do not depend on 'scripts/guix' since that would trigger a rebuild
+# even for people building from a tarball.
+doc/guix.1: $(sub_commands_mans)
+       -$(AM_V_HELP2MAN)$(gen_man) --output="$@" `basename "$@" .1`
+
+# Note: The dependency on $(GOBJECTS) is meant to force these docs to be made
+# only after all Guile modules have been compiled.  The 'case' ensures the man
+# pages are only generated if the corresponding script source has been
+# changed.
+doc/guix-%.1: guix/scripts/%.scm $(GOBJECTS)
+       address@hidden '$?' in \
+         *$<*) $(AM_V_P) && set -x || echo "  HELP2MAN $@"; \
+               $(gen_man) --output="$@" "guix $*";; \
+         *)    : ;; \
+       esac
 
 if BUILD_DAEMON
 
-dist_man1_MANS +=                              \
-  doc/guix-daemon.1
+dist_man1_MANS += doc/guix-daemon.1
+
+# Note: Do not depend on 'guix-daemon' since that would trigger a rebuild even
+# for people building from a tarball.
+doc/guix-daemon.1: nix/nix-daemon/guix-daemon.cc
+       -$(AM_V_HELP2MAN)$(gen_man) --output="$@" `basename "$@" .1`
 
 endif