From: David Masover on
A very simple template engine based on Regular Expressions.

gem install re_template


No meaningful changes, or changelog. From the README:


* Regular expressions or plain text
* Can be used for HTML->HTML (read on)
* Tested on Ruby 1.8.7 and 1.9.1


template =
template.expressions = {/\{foo\}/ => :foo, /\{bar\}/ => :bar}
template.parse! 'A {foo} is not a {bar}.'
template.render :foo => 'plant', :bar => 'rhinocerous', :other_expression =>
=> 'A plant is not a rhinocerous.'

Expressions must be set before parsing.
Multiple calls to parse! can be done with the same expressions (this may
Multiple calls to 'render' will work by design.
It also works with HTML:

template =
template.add_text_expressions '<foo>' => :foo, '|lang|' => :lang
template.parse! '<p>&lt;foo&gt; is not a valid |lang| tag.</p>'
template.render :foo => '<bar>', :lang => 'HTML'
=> '<p>&lt;bar&gt; is not a valid HTML tag.</p>'

Actually, I lied, as this will currently attach a doctype, and wrap things in
html and body tags, if any of these things are missing. I blame Nokogiri.

Read the specs for more.


Mail merge. A user can prepare an email like this, in their mail client:

Dear {customer_name},
Lorem ipsum dolor sit amet...

The curly brackets are merely a convention, because {user} is unlikely to be
intended in the body of a message. The important point is that this can also
be applied to an HTML message, even if the pattern or replacement text is not
valid HTML. For example:

Dear <customer_name>,

A simple text replacement would only see &lt;user&gt;. While we're at it, the
replacement text is automatically escaped.

I also looked at Liquid. It is very cool, but it was overkill for this
project, and it didn't look like it would behave well with WYSIWYG-generated


This is brand spanking this-afternoon new. [ed: not anymore, I haven't touched
it in a year.] The API is pretty much guaranteed to change. If you're using
this for anything important, either fork it or lock to a specific version.

The expressions hash is unordered. If you have a chunk of text that could
match two different regular expressions, one of them is going to be applied
first, and it's undefined which one. If this matters to you, you're probably
using the wrong tool -- personally, I won't be using the regexes directly at
all, they just seem to be faster (for some bizarre reason) than string#split.

Someone MUST have done a better job of this somewhere. If you find it, let me