Blue is a minimal in design, but full-featured template language for Ruby.
- template inheritance (the only template language in Ruby I'm aware of that does)
- blocks
- filters
- functions
- super convenient variable substitution
- has a loader that caches pre-generated templates
Currently version 0.9. It's nearly fully functional and seems stable but it still needs a few small features, needs to be battle tested more, and I need to learn how to make it a gem. Other todos before release include Tilt support, a nice interface for Sinatra, and partials/includes.
Also, I'm pretty new to Ruby so please feel free to offer style suggestions.
require 'blue'
loader = Blue::TemplateLoader.new './templates'
namespace = {:entries => Weblog.entries, :breadcrumbs => breadcrumbs}
loader.get(:weblog).render(namespace)
There are only a few constructs. Here's an example template, I'll include more documentation later.
@extends base
@block content
% prevday = nil
% entries.each do |entry|
% day = entry.creation_dt.strftime('%B %d, %Y')
% if day != prevday
<h2>
<a title="permanent link for $day" href="$entry.dateuri">$entry.creation_dt|datefmt('%A, %B %d, %Y')</a>
</h2>
%end
<h3><a href="$entry.url">$entry.title</a></h3>
$printEntry(entry)
% prevday = day
% end
<p>There were ${entries.length} entries, and you can print a dollar sign like ${'$'}.
Though of course a dollar sign won't be misinterpreted if it appears by itself $ or
as part of something that doesn't look like a variable reference (i.e. like money $3.50)</p>
@end
@def printEntry(entry)
<div id="id$entry.id">
<h3><a href="$entry.permalink">$entry.title</a></h3>
@filter off
$entry.rawhtml
@filter
</div>
@end
As you can see, a line starting with '%' just escapes out to Ruby code, and anything in a ${...} is a Ruby expression. Variable substitution is done by starting something that looks like a variable reference or function call with a dollar sign. Blue tries to be somewhat smart about what "looks like" a variable substitution but it's not foolproof. You can define functions, use filters, template inheritance, and so on.
MIT licensed