Perl 6 - Starting with the basics - Strings(encryption, Caesar chipher, rotating word, built-in functions(ord, chr))

Think Perl 6

開発環境

• macOS Sierra - Apple (OS)
• Emacs (Text Editor)
• Perl 6 (プログラミング言語)
• Rakudo(コンパイラ、実装)

Think Perl 6: How to Think Like a Computer Scientist (Laurent Rosenfeld(著)、Allen B. Downey(著)、Oreilly & Associates Inc)のPart 1(Starting with the basics)、Chapter 7(Strings)の Exercises 7-3.を取り組んでみる。

Exercises 7-3.

コード(Emacs)

#!/usr/bin/env perl6
# -*- coding: utf-8 -*-

sub rotate-word($word, $n) {
    my $result = '';
    my $m = $n % 26;
    for $word.comb -> $letter {
        my $k = $letter.ord + $m;
        $k -= 26 if 'Z'.ord < $k;
        $result = $result ~ $k.chr;
    }
    $result;
}

say rotate-word('IBM', -1);
say rotate-word('Z', 1);
my $word = 'PRRL';
say $word;
$word = rotate-word($word, 13);
say $word;
$word = rotate-word($word, 13);
say $word;

入出力結果(Terminal, REPL)

$ ./sample3.pl
HAL
A
PRRL
CEEY
PRRL
$