Some weak docs

Message-ID: <20011215005913.GC28596@blackrider>

p4raw-id: //depot/perl@13697

1 files changed, 35 insertions, 1 deletions

diff --git a/ext/B/B/Bblock.pm b/ext/B/B/Bblock.pm
index 9bef3ac3e1..624bae4f09 100644
--- a/ext/B/B/Bblock.pm
+++ b/ext/B/B/Bblock.pm
@@ -168,7 +168,12 @@ B::Bblock - Walk basic blocks
 
 =head1 SYNOPSIS
 
-	perl -MO=Bblock[,OPTIONS] foo.pl
+  # External interface
+  perl -MO=Bblock[,OPTIONS] foo.pl
+
+  # Programmatic API
+  use B::Bblock qw(find_leaders);
+  my $leaders = find_leaders($root_op, $start_op);
 
 =head1 DESCRIPTION
 
@@ -176,6 +181,35 @@ This module is used by the B::CC back end.  It walks "basic blocks".
 A basic block is a series of operations which is known to execute from
 start to finish, with no possiblity of branching or halting.
 
+It can be used either stand alone or from inside another program.
+
+=for _private
+Somebody who understands the stand-alone options document them, please.
+
+=head2 Functions
+
+=over 4
+
+=item B<find_leaders>
+
+  my $leaders = find_leaders($root_op, $start_op);
+
+Given the root of the op tree and an op from which to start
+processing, it will return a hash ref representing all the ops which
+start a block.
+
+=for _private
+The above description may be somewhat wrong.
+
+The values of %$leaders are the op objects themselves.  Keys are $$op
+addresses.
+
+=for _private
+Above cribbed from B::CC's comments.  What's a $$op address?
+
+=back
+
+
 =head1 AUTHOR
 
 Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>