From ae583ef458dd44698f1743aead7b771fb410d282 Mon Sep 17 00:00:00 2001
From: Ailbhe Tweedie <atweedie@protonmail.ch>
Date: Tue, 2 Apr 2019 18:16:12 +0200
Subject: 002-p5-02: document & clean-up script

---
 challenge-002/ailbhe-tweedie/perl5/ch-02.pl | 37 +++++++++++++++++++----------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/challenge-002/ailbhe-tweedie/perl5/ch-02.pl b/challenge-002/ailbhe-tweedie/perl5/ch-02.pl
index 05826d4efc..84d904ee09 100755
--- a/challenge-002/ailbhe-tweedie/perl5/ch-02.pl
+++ b/challenge-002/ailbhe-tweedie/perl5/ch-02.pl
@@ -12,6 +12,8 @@
 #
 # Test with:
 # >  echo {0..99} | ./ch-02.pl to | awk '{print $3}' | ./ch-02.pl from
+#
+# TODO: add tests
 
 use strict;
 use warnings;
@@ -20,6 +22,7 @@ use Data::Dump;
 
 use v5.10;
 
+# TODO: split the string right here into an array and don't keep the $BASE variable
 my $BASE = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXY";
 
 exit 1 unless @ARGV == 1;
@@ -47,45 +50,55 @@ exit 0;
 
 sub toBase35 {
 	my $input = shift;
+
 	my @base = split "", $BASE;
 	my @convert;
-	my $baseNum = @base;
 	my $max = 0;
+
+	# Figure out the highest power of the base we need by incrementing
+	# base^power until it is bigger than the input. The exponent we're
+	# looking for is 1 less.
 	while (1) {
-		last unless $baseNum ** ++$max <= $input;
+		last unless @base ** ++$max <= $input;
 	}
+
+	# Figure out the number's place values in a similar way by subtracting
+	# base^power from the input until the input is smaller than the value
+	# we're subtracting from it. The place values are saved in the array @convert.
 	while ($max > 0) {
 		my $exp = $max - 1;
-		#print "$baseNum to the $exp is ", $baseNum ** $exp, " which is smaller than $input\n";
-		my $pow = $baseNum ** $exp;
-		my $place = 0;
+		my $pow = @base ** $exp;
+		my $place;
 		while ($pow <= $input) {
 			$input -= $pow;
 			$place++;
-			#print "input $input; place $place\n";
 		}
 		push @convert, $place;
 		$max--;
 	}
-	#print "@convert: ";
-	#dd @convert;
-	#print "\n";
+
+	# Return our number in the new base, by indexing the @base array with
+	# the @convert array.
+	# TODO: figure out if this implict return is `bad style'
 	my $output = join "", @base[@convert];
 }
 
 sub fromBase35 {
-	my $input = shift; # APX
+	my $input = shift;
 
-	# create a hash converting a base35 alphanumeric character to a base10 value
+	# We create a hash converting an alphanumeric character in the new base to
+	# a base10 value
+	# TODO: move this out of the function
 	my %hash;
 	my @base = split "", $BASE;
 	for my $i (0..@base-1) {
 		$hash{$base[$i]} = $i;
 	}
 
-	my @based = split "", $input; #  (A, P, X)
+	my @based = split "", $input; # bad variable name
 	my $max = @based - 1;
 	my $output;
+	# TODO: A for loop would probably be more clear at this point.
 	while ($max >= 0) {
 		$output += ( @base ** $max ) * $hash{@based[@based - $max - 1]};
 		$max--;
-- 
cgit