From 55f82a803e59ad68a56714ddf008b4f82baea3a3 Mon Sep 17 00:00:00 2001
From: Stefano Lattarini <stefano.lattarini@gmail.com>
Date: Mon, 27 May 2013 10:44:06 +0200
Subject: [PATCH] Automake::Rule: expose suffix rules as a function, not a
 scalar

This is just a preparatory refactoring in view of future patches.
No semantic change is intended.

* lib/Automake/Rule.pm ($suffix_rules): Turn from a package-level
variable to a lexical variable.
(suffix_rule): New function, expose the details of $suffix_rules
that are actually required by code outside thus modules --- and
only those details, no more.
(@EXPORT): Adjust.
* automake.in (derive_suffix): Likewise.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>
---
 automake.in          |  9 ++++-----
 lib/Automake/Rule.pm | 20 +++++++++++++++++---
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/automake.in b/automake.in
index ef2cf6d..7829875 100644
--- a/automake.in
+++ b/automake.in
@@ -5990,12 +5990,11 @@ sub derive_suffix ($$)
 {
   my ($source_ext, $obj) = @_;
 
-  while (! $extension_map{$source_ext}
-	 && $source_ext ne $obj
-	 && exists $suffix_rules->{$source_ext}
-	 && exists $suffix_rules->{$source_ext}{$obj})
+  while (!$extension_map{$source_ext} && $source_ext ne $obj)
     {
-      $source_ext = $suffix_rules->{$source_ext}{$obj}[0];
+      my $new_source_ext = suffix_rule ($source_ext, $obj);
+      last if not defined $new_source_ext;
+      $source_ext = $new_source_ext;
     }
 
   return $source_ext;
diff --git a/lib/Automake/Rule.pm b/lib/Automake/Rule.pm
index 47f3a9d..5f6f3a2 100644
--- a/lib/Automake/Rule.pm
+++ b/lib/Automake/Rule.pm
@@ -29,8 +29,8 @@ use Automake::DisjConditions;
 require Exporter;
 use vars '@ISA', '@EXPORT', '@EXPORT_OK';
 @ISA = qw/Automake::Item Exporter/;
-@EXPORT = qw (reset register_suffix_rule suffix_rules_count
-	      suffixes rules $suffix_rules $KNOWN_EXTENSIONS_PATTERN
+@EXPORT = qw (reset register_suffix_rule suffix_rules_count suffix_rule
+	      suffixes rules $KNOWN_EXTENSIONS_PATTERN
 	      depend %dependencies %actions register_action
 	      accept_extensions
 	      reject_rule msg_rule msg_cond_rule err_rule err_cond_rule
@@ -154,7 +154,7 @@ C<register_suffix_rule> function.
 
 =cut
 
-use vars '$suffix_rules';
+my $suffix_rules;
 
 =item C<$KNOWN_EXTENSIONS_PATTERN>
 
@@ -384,6 +384,20 @@ sub reset()
   %actions = ();
 }
 
+=item C<suffix_rule ($ext, $obj)>
+
+XXX
+
+=cut
+
+sub suffix_rule ($$)
+{
+  my ($source_ext, $obj) = @_;
+  return undef unless (exists $suffix_rules->{$source_ext} and
+                       exists $suffix_rules->{$source_ext}{$obj});
+  return $suffix_rules->{$source_ext}{$obj}[0];
+}
+
 =item C<register_suffix_rule ($where, $src, $dest)>
 
 Register a suffix rule defined on C<$where> that transforms
-- 
2.7.4