Clean up PGrandom.pm

Author: drgrice1

lib/PGrandom.pm

@@ -1,6 +1,7 @@
 package PGrandom;
 
 use strict;
+use warnings;
 
 my $multiplier = 69069;
 
@@ -9,69 +10,64 @@ my $translate = 1;
 my $modulus = 2**32;
 
 sub new {
-	my $class = shift;
-	my $seed  = shift;
+	my ($class, $seed) = @_;
 
-	$seed = 1 unless defined($seed);
+	$seed //= 1;
 	my $original_seed = $seed;
 	$seed = mod($multiplier * $seed + $translate, $modulus);
 	my $self = {
-		'seed'            => $seed,
-		'original_seed'   => $original_seed,    # this and the next value are largely for debugging
-		'number_of_calls' => 1                  # there is always one call to set the seed.
+		seed            => $seed,
+		original_seed   => $original_seed,    # This and the next value are largely for debugging.
+		number_of_calls => 1                  # There is always one call to set the seed.
 	};
 
-	bless $self, $class;
-
-	return $self;
+	return bless $self, $class;
 }
 
-sub mod {    # for some reason perl's % doesn't seem to work for large numbers?
-	my $a = shift;
-	my $b = shift;
-	$a - int($a / $b) * $b;
+# Perl's % modulus operator does not work for large numbers. So use mod here instead. Although, does this ever actually
+# need to handle numbers greater than 2^63 - 1 which is where the % operator fails? I think this dates back to the days
+# of 32 bit integers being used.
+sub mod {
+	my ($m, $n) = @_;
+	return $m - int($m / $n) * $n;
 }
 
 sub random {
-	my $self  = shift;
-	my $begin = shift;
-	my $end   = shift;
-	my $incr  = shift;
-	my $out;
-	$self->{'number_of_calls'}++;
-	$incr = 1 unless defined($incr);
+	my ($self, $begin, $end, $incr) = @_;
+	++$self->{number_of_calls};
+	$incr //= 1;
 	my $seed     = $self->{'seed'};
 	my $new_seed = mod($multiplier * $seed + $translate, $modulus);
-	$self->{'seed'} = $new_seed;
+	$self->{seed} = $new_seed;
 
 	unless ($incr <= 0) {
-		$out = $begin + $incr * int(($new_seed / ($modulus)) * (int(($end - $begin) / $incr) + 1));
-	} else {    # if $incr is less than zero return "continuous" distribution
-		$out = $begin + ($end - $begin) * $new_seed / $modulus;
+		# If $incr is less than zero, then return a "continuous" distribution.
+		return $begin + $incr * int(($new_seed / ($modulus)) * (int(($end - $begin) / $incr) + 1));
+	} else {
+		return $begin + ($end - $begin) * $new_seed / $modulus;
 	}
-	$out;
-
 }
 
 sub rand {
-	my $self = shift;
-	my $end  = shift;
-	$end = 1 unless defined($end);
-	$self->random(0, $end, 0);
+	my ($self, $end) = @_;
+	$end //= 1;
+	return $self->random(0, $end, 0);
 }
 
 sub srand {
-	my $self     = shift;
-	my $new_seed = shift;
-	$self->{'original_seed'}   = $new_seed;
-	$new_seed                  = mod($multiplier * $new_seed + $translate, $modulus);    # reset the seed
-	$self->{'number_of_calls'} = 1;
-	$self->{'seed'}            = $new_seed;
+	my ($self, $new_seed) = @_;
+	$self->{original_seed}   = $new_seed;
+	$new_seed                = mod($multiplier * $new_seed + $translate, $modulus);    # reset the seed
+	$self->{number_of_calls} = 1;
+	$self->{seed}            = $new_seed;
+	return;
 }
 
-sub seed {    #synonym for srand
-	my $self = shift;
-	$self->srand(@_);
+# This is a synonym for srand.
+sub seed {
+	my ($self, $new_seed) = @_;
+	$self->srand($new_seed);
+	return;
 }
 
 1;