#!/usr/bin/env perl
#    Sample usage:  man sh | jack.pl
#                   jack.pl -c -j jack.pl
# (Based on jack.c by Jamie Zawinski.)

use strict;

my( $text, $keep, $work );

$text = "All work and no play makes Jack a dull boy.  ";
$keep = qr<\t>;

while( 1 ) {
    $ARGV[0] =~ /-c/ and do
      { $keep = qr<[][;#(){}"]|/\*|\*/|//>; shift; next; };
    $ARGV[0] =~ /-j/ and do
      { $text = "Just another Perl hacker.  "; shift; next; };
    last;
}

while( <> ) {
    # Stupid `man` formatting
    s/.\10//g;  s/[^[:space:][:graph:]]//gs;

    # Expand tabs
    1 while s/\t+/' ' x (length($&)*8 - length($`)%8)/e;

    xify( split /($keep|(?:\A|\z|\s){4,})/s )
}

sub xify {
    print rep( shift ), shift
      while @_
}

sub rep {
    my( $len, $s, @s, $i );

    $s = shift;
    return "" unless $len = length $s;

    ($s, $work) = ($work . $text x (1 + (length($s) - length $work) / length $text))
      =~ m/^(.{0,@{[length $s]}})(?=\s|\A|\z)\s*(.*)/s;

    @s = split /\s(?=\S)/, $s;
    return $s . ' ' x ($len - length $s) if @s < 2;

    $s[-1] =~ s/\s+$//;
    for( @s ) { $len -= length $_ }
    for( $i = 0; $len--; $i = ($i+1) % $#s ) {
	$s[$i] .= ' '
    }
    join "", @s
}