Perl 6 - Starting with the basics - Functions(subroutines, right-justify, grid, repeat)

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 3(Functions)のExercises 3-1、2.を取り組んでみる。

Exercises 3-1、2.

コード(Emacs)

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

say '3-1.';
sub right-justify($input-string) {
    say ' ' x (70 - $input-string.chars) ~ $input-string;
}

right-justify 'Larry Wall';

sub right-justify1($input-string) {
    ' ' x (70 - $input-string.chars) ~ $input-string;
}

say chars(right-justify1 'Larry Wall') == 70;

say '3-2.';
sub do-twice($code, $value) {
    $code($value);
    $code($value);
}
sub greet {
    say 'Hello World!';
}
sub print-twice($value) {
    say $value;
    say $value;
}

do-twice(&print-twice, "What's up doc");

sub do-four($code, $value) {
    do-twice($code, $value);
    do-twice($code, $value);
}

do-four(&print-twice, "What's up doc 2");

say '3-3.';


sub grid {
    print '+';
    say ' - - - - +' x 2;
    do-four(&say,'|         |         |');
    print '+';
    say ' - - - - +' x 2;
    do-four(&say,'|         |         |');
    print '+';
    say ' - - - - +' x 2;
}

grid;

sub grid4 {
    print '+';
    say ' - - - - +' x 4;
    do-four(&say,'|         |         |         |         |');
    print '+';
    say ' - - - - +' x 4;
    do-four(&say,'|         |         |         |         |');
    print '+';
    say ' - - - - +' x 4;
    do-four(&say,'|         |         |         |         |');
    print '+';
    say ' - - - - +' x 4;
    do-four(&say,'|         |         |         |         |');
    print '+';
    say ' - - - - +' x 4;
}

grid4;

入出力結果(Terminal, REPL)

$ ./sample1.pl 
3-1.
                                                            Larry Wall
True
3-2.
What's up doc
What's up doc
What's up doc
What's up doc
What's up doc 2
What's up doc 2
What's up doc 2
What's up doc 2
What's up doc 2
What's up doc 2
What's up doc 2
What's up doc 2
3-3.
+ - - - - + - - - - +
|         |         |
|         |         |
|         |         |
|         |         |
+ - - - - + - - - - +
|         |         |
|         |         |
|         |         |
|         |         |
+ - - - - + - - - - +
+ - - - - + - - - - + - - - - + - - - - +
|         |         |         |         |
|         |         |         |         |
|         |         |         |         |
|         |         |         |         |
+ - - - - + - - - - + - - - - + - - - - +
|         |         |         |         |
|         |         |         |         |
|         |         |         |         |
|         |         |         |         |
+ - - - - + - - - - + - - - - + - - - - +
|         |         |         |         |
|         |         |         |         |
|         |         |         |         |
|         |         |         |         |
+ - - - - + - - - - + - - - - + - - - - +
|         |         |         |         |
|         |         |         |         |
|         |         |         |         |
|         |         |         |         |
+ - - - - + - - - - + - - - - + - - - - +
$