From base35

1 files changed, 16 insertions, 3 deletions

diff --git a/challenge-002/john-barrett/perl5/ch-2.pl b/challenge-002/john-barrett/perl5/ch-2.pl
index 3293529824..f18215e4f0 100755
--- a/challenge-002/john-barrett/perl5/ch-2.pl
+++ b/challenge-002/john-barrett/perl5/ch-2.pl
@@ -2,7 +2,7 @@
 
 use strict;
 use warnings;
-use feature 'say';
+use feature qw/ say /;
 
 # Usage, e.g.
 # ./ch-2.pl -to-base35 123
@@ -13,7 +13,21 @@ my @charset = ( 0..9, 'A'..'Y' );
 my $base = @charset;
 
 say to_base35( $args{'-to-base35'} ) if $args{'-to-base35'};
-#say to_base35( $args{'-to-base35'} ) if $args{'-to-base35'};
+say from_base35( $args{'-from-base35'} ) if $args{'-from-base35'};
+
+sub from_base35 {
+    my ( $base35 ) = @_;
+    my $sign = $base35 =~ s/-//g ? '-' : '';
+    my @digits = split '', $base35;
+    my $idx = join '', @charset;
+    my $pos = 0;
+    my $val;
+    while ( my $char = pop @digits ) {
+        $val += index( $idx, $char ) * ( $base ** $pos );
+        $pos++;
+    }
+    $sign . $val;
+}
 
 sub to_base35 {
     my ( $int ) = @_;
@@ -23,7 +37,6 @@ sub to_base35 {
     do {
         push @digits, $charset[ $int % $base ];
         $int = int( $int / $base );
-        say $int;
     } while ( $int > 0 );
     $sign . join '', reverse @digits;
 }