[PATCH] {master} missing: better tips about missing tools

[Stefano Lattarini]

* lib/missing: Try to point the user to the home page of such tools
where possible.  Also, make clear that some tools (e.g., aclocal or
autoheader) are distributed as part of bigger projects (resp. automake
and autoconf, in those cases).  While at it, refactor and re-format
the existing code heavily, in particular introducing
(give_advice): ... this new function in the process.

Signed-off-by: Stefano Lattarini <address@hidden>
---

 I plan to push this by this evening if there is no objection.

 lib/missing |  196 ++++++++++++++++++++++++++++++-----------------------------
 1 file changed, 100 insertions(+), 96 deletions(-)

diff --git a/lib/missing b/lib/missing
index 06e0af1..b24ebab 100755
--- a/lib/missing
+++ b/lib/missing
@@ -1,7 +1,7 @@
 #! /bin/sh
 # Common wrapper for a few potentially missing GNU programs.
 
-scriptversion=2012-06-14.10; # UTC
+scriptversion=2012-06-23.01; # UTC
 
 # Copyright (C) 1996-2012 Free Software Foundation, Inc.
 # Originally written by Fran,cois Pinard <address@hidden>, 1996.
@@ -104,102 +104,106 @@ else
   exit $st
 fi
 
-# Normalize program name to check for.
-program=`echo "$1" | sed '
-  s/^gnu-//; t
-  s/^gnu//; t
-  s/^g//; t'`
-
-# If it does not exist, or fails to run (possibly an outdated version),
-# advise the user how to get it.
-case $program in
-
-  aclocal*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified 'acinclude.m4' or '${configure_ac}'.  You might want
-         to install the Automake and Perl packages.  Grab them from
-         any GNU archive site."
+perl_URL=http://www.perl.org/
+flex_URL=http://flex.sourceforge.net/
+gnu_software_URL=http://www.gnu.org/software
+
+program_details ()
+{
+  case $1 in
+    aclocal|automake)
+      echo "The '$1' program is part of the GNU Automake package:"
+      echo "<$gnu_software_URL/automake>"
+      echo "It also requires GNU Autoconf, GNU m4 and Perl in order to run:"
+      echo "<$gnu_software_URL/autoconf>"
+      echo "<$gnu_software_URL/m4/>"
+      echo "<$perl_URL>"
+      ;;
+    autoconf|autom4te|autoheader)
+      echo "The '$1' program is part of the GNU Autoconf package:"
+      echo "<$gnu_software_URL/autoconf/>"
+      echo "It also requires GNU m4 and Perl in order to run:"
+      echo "<$gnu_software_URL/m4/>"
+      echo "<$perl_URL>"
+      ;;
+  esac
+}
+
+give_advice ()
+{
+  # Normalize program name to check for.
+  normalized_program=`echo "$1" | sed '
+    s/^gnu-//; t
+    s/^gnu//; t
+    s/^g//; t'`
+
+  printf '%s\n' "'$1' is $msg."
+ 
+  configure_deps="'${configure_ac}' or m4 files included by '${configure_ac}'"
+  case $normalized_program in
+    autoconf*)
+      echo "You should only need it if you modified '${configure_ac}',"
+      echo "or m4 files included by it."
+      program_details 'autoconf'
+      ;;
+    autoheader*)
+      echo "You should only need it if you modified 'acconfig.h' or"
+      echo "$configure_deps."
+      program_details 'autoheader'
+      ;;
+    automake*)
+      echo "You should only need it if you modified 'Makefile.am' or"
+      echo "$configure_deps."
+      program_details 'automake'
+      ;;
+    aclocal*)
+      echo "You should only need it if you modified 'acinclude.m4' or"
+      echo "$configure_deps."
+      program_details 'aclocal'
+      ;;
+   autom4te*)
+      echo "You might have modified some maintainer files that require"
+      echo "the 'automa4te' program to be rebuilt."
+      program_details 'autom4te'
+      ;;
+    bison*|yacc*)
+      echo "You should only need it if you modified a '.y' file."
+      echo "You may want to install the GNU Bison package:"
+      echo "<$gnu_software_URL/bison/>"
+      ;;
+    lex*|flex*)
+      echo "You should only need it if you modified a '.l' file."
+      echo "You may want to install the Fast Lexical Analyzer package:"
+      echo "<$flex_URL>"
+      ;;
+    help2man*)
+      echo "You should only need it if you modified a dependency" \
+           "of a man page."
+      echo "You may want to install the GNU Help2man package:"
+      echo "<$gnu_software_URL/help2man/>"
     ;;
-
-  autoconf*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified '${configure_ac}'.  You might want to install the
-         Autoconf and GNU m4 packages.  Grab them from any GNU
-         archive site."
-    ;;
-
-  autoheader*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified 'acconfig.h' or '${configure_ac}'.  You might want
-         to install the Autoconf and GNU m4 packages.  Grab them
-         from any GNU archive site."
-    ;;
-
-  automake*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified 'Makefile.am', 'acinclude.m4' or '${configure_ac}'.
-         You might want to install the Automake and Perl packages.
-         Grab them from any GNU archive site."
-    ;;
-
-  autom4te*)
-    echo 1>&2 "\
-WARNING: '$1' is needed, but is $msg.
-         You might have modified some files without having the
-         proper tools for further handling them.
-         You can get '$1' as part of Autoconf from any GNU
-         archive site."
-    ;;
-
-  bison*|yacc*)
-    echo 1>&2 "\
-WARNING: '$1' $msg.  You should only need it if
-         you modified a '.y' file.  You may need the Bison package
-         in order for those modifications to take effect.  You can get
-         Bison from any GNU archive site."
-    ;;
-
-  lex*|flex*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified a '.l' file.  You may need the Flex package
-         in order for those modifications to take effect.  You can get
-         Flex from any GNU archive site."
-    ;;
-
-  help2man*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-        you modified a dependency of a manual page.  You may need the
-        Help2man package in order for those modifications to take
-        effect.  You can get Help2man from any GNU archive site."
-    ;;
-
-  makeinfo*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified a '.texi' or '.texinfo' file, or any other file
-         indirectly affecting the aspect of the manual.  The spurious
-         call might also be the consequence of using a buggy 'make' (AIX,
-         DU, IRIX).  You might want to install the Texinfo package or
-         the GNU make package.  Grab either from any GNU archive site."
-    ;;
-
-  *)
-    echo 1>&2 "\
-WARNING: '$1' is needed, and is $msg.
-         You might have modified some files without having the
-         proper tools for further handling them.  Check the 'README' file,
-         it often tells you about the needed prerequisites for installing
-         this package.  You may also peek at any GNU archive site, in case
-         some other package would contain this missing '$1' program."
-    ;;
-
-esac
+    makeinfo*)
+      echo "You should only need it if you modified a '.texi' file, or"
+      echo "any other file indirectly affecting the aspect of the manual."
+      echo "You might want to install the Texinfo package:"
+      echo "<$gnu_software_URL/texinfo/>"
+      echo "The spurious makeinfo call might also be the consequence of"
+      echo "using a buggy 'make' (AIX, DU, IRIX), in which case you might"
+      echo "want to install GNU make:"
+      echo "<$gnu_software_URL/make/>"
+      ;;
+    *)
+      echo "You might have modified some files without having the proper"
+      echo "tools for further handling them.  Check the 'README' file, it"
+      echo "often tells you about the needed prerequisites for installing"
+      echo "this package.  You may also peek at any GNU archive site, in"
+      echo "case some other package contains this missing '$1' program."
+      ;;
+  esac
+}
+
+give_advice "$1" | sed -e '1s/^/WARNING: /' \
+                       -e '2,$s/^/         /' >&2
 
 # Propagate the correct exit status (expected to be 127 for a program
 # not found, 63 for a program that failed due to version mismatch).
-- 
1.7.9.5