devel/mktodo: Add some comments

(cherry picked from commit e00ce51fae01f6ca67ee85158d42d483ede947e2)
Signed-off-by: Nicolas R <atoomic@cpan.org>

diff --git a/dist/Devel-PPPort/devel/mktodo b/dist/Devel-PPPort/devel/mktodo
index e7014f0..11ea19c 100755 (executable)
--- a/dist/Devel-PPPort/devel/mktodo
+++ b/dist/Devel-PPPort/devel/mktodo
@@ -3,6 +3,9 @@
 #
 #  mktodo -- generate baseline and todo files by running mktodo.pl
 #
+# It calls plain 'mktodo' on each perl version it finds based on the input
+# parameters.
+#
 ################################################################################
 #
 #  Version 3.x, Copyright (C) 2004-2013, Marcus Holland-Moritz.
@@ -20,13 +23,30 @@ use Getopt::Long;
 require './devel/devtools.pl';
 
 our %opt = (
-  base    => 0,
-  check   => 1,
+  base    => 0,     # If specified, this will generate base files, not todo ones
+  check   => 1,     # Do extra checking
   verbose => 0,
   install => '/tmp/perl/install/default',
   blead   => 'bleadperl-debug',
 );
 
+# The way this works, is it expects to find perl binaries for a bunch of
+# different versions in a given directory.  This defaults to the 'install' one
+# listed above, but is overriddable by the --install parameter.  It also uses
+# blead, again with an overridable default.
+#
+# It first verifies that the test file works properly for blead.
+#
+# Then it goes through the list of perl binaries sorted in decreasing order of
+# version number.  If something works in version n, but not in version n-1,
+# that means it was introduced (or perhaps fixed) in version n, and adds that
+# thing to the version n list.
+#
+# After everything is done, we have lists of what got added when.  The --base
+# parameter tells it to not use ppport.h when computing this.  Thus we get
+# what the official perls added when.  Without this parameter, we do use
+# ppport.h, so we get, as patched by ppport.h, what gets added when
+
 GetOptions(\%opt, qw( base check! verbose install=s blead=s blead-version=s )) or die;
 
 identify();