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4d47's solution

to Hello World in the Perl 6 Track

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Instructions
Test suite
Solution

The classical introductory exercise. Just say "Hello, World!".

"Hello, World!" is the traditional first program for beginning programming in a new language or environment.

The objectives are simple:

  • Write a function that returns the string "Hello, World!".
  • Run the test suite and make sure that it succeeds.
  • Submit your solution and check it at the website.

If everything goes well, you will be ready to fetch your first real exercise.

Resources

Remember to check out the Perl 6 documentation and resources pages for information, tips, and examples if you get stuck.

Running the tests

There is a test suite and module included with the exercise. The test suite (a file with the extension .t) will attempt to run routines from the module (a file with the extension .pm6). Add/modify routines in the module so that the tests will pass! You can view the test data by executing the command perl6 --doc *.t (* being the name of the test suite), and run the test suite for the exercise by executing the command prove6 . in the exercise directory.

Source

This is an exercise to introduce users to using Exercism http://en.wikipedia.org/wiki/%22Hello,_world!%22_program

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

hello-world.t

#!/usr/bin/env perl6
use v6;
use Test;
use lib $?FILE.IO.dirname; #`[Look for the module inside the same directory as this test file.]
use HelloWorld;
plan 1; #`[This is how many tests we expect to run.]

# Run the 'is' subroutine from the 'Test' module, with three arguments.
is(
  hello,           # Run the 'hello' subroutine, which is imported from your module.
  'Hello, World!', # The expected result to compare with 'hello'.
  'Say Hi!'        # The test description.
);
unit module HelloWorld:ver<1>;

sub hello(Str $name? --> Str) is export {
    "Hello, {$name || 'World'}!"
}

What can you learn from this solution?

A huge amount can be learnt from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.

Here are some questions to help you reflect on this solution and learn the most from it.

  • What compromises have been made?
  • Are there new concepts here that I could read more about to develop my understanding?

Community comments

See what others have said about this solution
almost 2 years ago
4d47 says

Remove default value on optional param, thanks @mienaikageb :)