#!/usr/bin/perl
#acro, a program to come up with a random acronym.
#copyright 1999 by thomas smith.  released under the GNU general public license.
$version = "2.1.02";

# Wow, on the day after i release this, someone comes up with a use!  random passwords!
#thanks, carlos.

srand(time ^ ($$ + ($$<<30)));
# maximum and minimum number of characters to generate by default.
$max = 7;
$min = 3;
# $letters is the number of letters in the acronym.  $presetletters is set if an argument
# was specified for the number of letters.
$letters = $presetletters = 0;
# acronym is uppercase (this is a default)? 1=yes, 0=no.
$uppercase = 1;
# $otherchars is set if the invoker supplied a character class to chose from.
$otherchars = 0;
# @goodchars is used if the invoker supplied a character class to chose from.  it is an array
# of characters to chose from.
@goodchars = ();
#debugging:$random = rand(127); print "Sample random number less than 127: $random\n";

# test for arguments.
foreach $arg (@ARGV) {  # go through the arguments.
    chomp $arg;
    if ($arg =~ /-h/i) {
        print "acro, by Thomas Smith, released under the GPL.  Version $version.\n";
        print "generates a random acronym, and prints it to STDOUT.\n";
        print "INVOCATION:\n";
        print "acro [ --help | --version ]\n";
        print "acro [ - | number ] { [ --lowercase | -l ] | [ --uppercase | -u ] [ -nlines ]}\n";
        exit 0;
    }
    elsif ($arg =~ /-v/i) {
        print "acro, by Thomas Smith, released under the GPL.  Version $version.\n";
        exit 0;
    }
    elsif ($arg =~ /^-u(.+)/i) { # this makes no sense unless the thing is a character class.
        # for instance, -u'[A-Za-z1380]' makes sense, but -u'hi' doesn't, since no one character
        # will match "hi".  -uh does, if you want h to be the only character in your acronym.
        $re = $1;
        $otherchars = 1;
    }
    elsif ($arg =~ /-n\s*(\d+)/) {
        $howmanyacros = $1;
    }
    elsif ($arg =~ /-l/i) {
        $uppercase = 0;
    }
    elsif ($arg =~ /-u/i) {
        $uppercase = 1;
    }
    elsif ($arg =~ /^-$/) {
        $letters = <STDIN>;
	if ($letters) {
	    $presetletters = 1;
	}
    }
    elsif ($arg =~ /\d+/) {
        $presetletters = 1;
        $letters = $arg;
    }
}
# okay, now the actual program starts.


if ($otherchars) { #set up the array of good characters, if we got the argument to use a custom set.
    for ($chrn = 0; $chrn < 128; $chrn += 1) {
        $curchr = chr($chrn);
        if ($curchr =~ /$re/) {
            push @goodchars, $curchr;
        }
    }
}

# newchar will find a new value for $char, one character.
if (!$otherchars) {
    $newchar = sub {
        $charnum = int(rand(26)); # integer part of a random number, will be 0..25.
        # add 97 to it (a is ASCII 97).
        $charnum += 97;
        $char = chr($charnum);    # convert number to character.
        if ($uppercase) {
            $char = uc($char);
        }
        return $char;
    }
}
else {
    $newchar = sub {
        $charnum = int(rand($#goodchars + 1));
        $char = $goodchars[$charnum];
        return $char;
    }
}

if (!defined($howmanyacros)) { 
    $howmanyacros=1;
}

for ($acrosdone = 0; $acrosdone < $howmanyacros; $acrosdone = $acrosdone + 1) {
    if (!$presetletters) {  #if the number of letters wasn't specified, make a random number.
	$letters = 0; #to eliminate spillover.
        until ($letters > $min) { $letters = rand($max); }
    }
    $acro = $char = "";
    #debugging:print "generacting acronym, $letters letters long...\n";
    $i = 1; # initialize i
    until ($i > $letters) {
        &$newchar;
        $acro .= $char;   # append $char to $acro, which is "" to start with.
        #debugging:print "\n **** $acro\n";
        $i += 1;
    }
print "$acro\n";
}
#debugging:print "for loop is done.\n";