Perl 6 - Starting with the basics - Fruitful subroutines(Incremental development, hypotenuse)

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 5(Fruitful subroutines)の Incremental development の Exercise.を取り組んでみる。

Incremental development の Exercise.

コード(Emacs)

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

sub hypotenuse0($x, $y) {
    return 0.0;
}

say hypotenuse1(3, 4);

sub hypotenuse1($x, $y) {
    say '$x is ', $x;
    say '$y is ', $y;
    return 0.0;
}

say hypotenuse1(3, 4);

sub hypotenuse2($x, $y) {
    my $xsquared = $x * $x;
    my $ysquared = $y * $y;
    say '$xsquared is ', $xsquared;
    say '$ysquared is ', $ysquared;
    return 0.0;
}

say hypotenuse2(3, 4);

sub hypotenuse3($x, $y) {
    my $xsquared = $x * $x;
    my $ysquared = $y * $y;
    my $squared = $xsquared + $ysquared;
    say '$squared is ', $squared;
    return 0.0;
}

say hypotenuse3(3, 4);

sub hypotenuse($x, $y) {
    my $xsquared = $x * $x;
    my $ysquared = $y * $y;
    my $squared = $xsquared + $ysquared;
    my $result = sqrt $squared;
    return $result;
}

say hypotenuse(3, 4);
say hypotenuse(3, 4) == 5;

入出力結果(Terminal, REPL)

$ ./sample_hypotenuse.pl
$x is 3
$y is 4
0
$x is 3
$y is 4
0
$xsquared is 9
$ysquared is 16
0
$squared is 25
0
5
True
$