#!/usr/bin/perl -w
# usage: $0 filename [optional output file]
# If the output file is not specified, it will print to STDOUT

use strict;

my $outp;

open FILE, $ARGV[0] or die "A grim and horrible death: $!";
if ( defined( $ARGV[1] ) ) {
    open OUTP, ">$ARGV[1]" or die "Couldn't write: $!";
    $outp = \*OUTP;
}
else {
    $outp = \*STDOUT;
}

my ( %calls, $name, @context );
#---
# First parsing phase is to try to gather all the return codes together,
# keyed by the function name
#---
while ( <FILE> ) {
     next if /^\s*#/;
    next if /^\s*$/;
    last if /__END__/;

    $name = $1 if /^sub (\w+)/;

    #---
    # Push the context and get next line if possible
    #---
    if ( /^\s*return (\$?[\w->:]+) (if .+)[;{]$/ ||
        /^\s*return (\$?[\w->:]+) (unless .+)[;{]$/ ) {
        my ( $code, $context ) = ( $1, $2 );

        chomp $context;
        $context =~ s/^\s+//;

        push @{$calls{$name}{$code}}, $context;
        next;
    }

    if ( /(.+){$/ ) {
        chomp;
        s/^\s+//;
        push @context, $_ 
    }

    pop  @context if ( /}$/ );

    push(@{$calls{$name}{$1}}, $context[-1]),next if ( /\s*return (\$?[\w->:{}]+
)/ );
}
close FILE;

for my $name ( sort keys %calls ) {
    for my $rc ( sort keys %{$calls{$name}} ) {
        print $outp "$rc when:\n\t";
        local $" = "\n\t";
        print $outp "@{$calls{$name}{$rc}}\n";
    }
}