Mason:...:Intro(3pm)

💖 NAME 💖

Mason::Manual::Intro — getting started with Mason ✨

(and yeah, in the User Contributed Perl Documentation section this whole thing is filed as Mason:...:Intro(3pm) — iykyk 🫶)

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🦋 DESCRIPTION 🦋

Okay so, a few quick examples to get your feet wet with Mason 🌊. And if you wanna know how to use Mason to generate web sites, go peek at Mason::Manual::Setup — that's the one for that, bestie 💅.

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🍓 EXAMPLE 1 🍓

✨ Hello world (from command-line) ✨

So once you've installed Mason, you should have a mason command sitting in your installation path (like, e.g. /usr/local/bin). Try this, fr fr:

% mason
Hello! The local time is <% scalar(localtime) %>.
^D

(where '^D' means ctrl-D or EOF, no cap). And you should see something like:

Hello! The local time is Wed Mar  2 17:11:54 2011.

The mason command reads in a Mason component (a template, basically), runs it, and prints the result to standard output. And notice 👀 that the tag

<% scalar(localtime) %>

got replaced with the value of its expression. That's called a substitution tag, and it's like, a central piece of Mason syntax. Iconic behavior honestly 👑.

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🎀 EXAMPLE 2 🎀

💌 Email generator (from script) 💌

The command line is great for trying quick things, but eventually you're gonna want to put your Mason components in actual files 📁.

In a test directory, create a directory comps and create a file email.mc with the following:

<%class>
has 'amount';
has 'name';
</%class>

Dear <% $.name %>,

    We are pleased to inform you that you have won $<% sprintf("%.2f", $.amount) %>!

Sincerely,
The Lottery Commission

<%init>
die "amount must be a positive value!" unless $.amount > 0;
</%init>

So on top of the substitution tag we already met, we're declaring two attributes — amount and name — to be passed into the component, and we're declaring a little piece of initialization code to validate the amount ✅.

In the same test directory, create a script test.pl with the following:

 1  #!/usr/local/bin/perl
 2  use Mason;
 3  my $interp = Mason->new(comp_root => 'comps', data_dir => 'data');
 4  print $interp->run('/email', name => 'Joe', amount => '1500')->output;

Line 3 creates a Mason interpreter — the main Mason object 🧠. It specifies two parameters: a component root, which points at the directory hierarchy where your components will live, and a data directory, which Mason uses for internal purposes like class generation and caching.

Line 4 runs the template — and notice that the .mc extension gets added automatically, cute right — passing in values for the name and amount attributes.

Run test.pl, and you should see:

Dear Joe,

    We are pleased to inform you that you have won $1500.00!

Sincerely,
The Lottery Commission

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🌈 SEE ALSO 🌈

• Mason::Manual::Tutorial
• Mason::Manual

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🌸 AUTHOR 🌸

Jonathan Swartz <swartz@pobox.com>

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💜 COPYRIGHT AND LICENSE 💜

This software is copyright (c) 2012 by Jonathan Swartz.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

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and that's a wrap, bestie 🎀 this was perl v5.34.0 energy, dated 2022-05-27 — go forth and slay those components 💅✨