#!/usr/bin/perl

#
# For an internet draft of the form "draft-foo-bar-gork-03.txt",
# returns the previous version of the draft (e.g., -02).
#
# Updated:
#    4/6/07 rcg now ignores fluff between digits and dot
#               (e.g., "b" in "draft-ietf-eai-smtpext-05b.txt")
#
{
$foo = $ARGV[0];
if ( not $foo =~ /(.+-)([0-9]+)[^\.]*(.*)/ )
{
    printf stderr "\"$ARGV[0]\" doesn't seem to be an I-D\n";
    exit 1;
}

$base  = $1;
$vers  = $2;
$ext   = $3;

if ( $vers == 0 )
{
    printf stderr "Version is 00\n";
    exit 1;
}

$targ = $vers - 1;

if ( $targ < 10 ) { $fill = "0"; }

print "${base}${fill}${targ}${ext}\n";
}