# Re\_template 0.0.1.2

**URL:** <https://www.ruby-forum.com/t/re-template-0-0-1-2/179403>\
**Category:** Ruby\
**Created:** [November 24, 2009, 6:44am UTC](https://www.ruby-forum.com/t/re-template-0-0-1-2/179403 "2009-11-24T06:44:29Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![dgm](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/df788c/32.png) [@dgm](https://www.ruby-forum.com/u/dgm)\
**Post date:** [November 24, 2009, 6:44am UTC](https://www.ruby-forum.com/t/re-template-0-0-1-2/179403/1 "2009-11-24T06:44:29Z")

</div>

A very simple template engine based on Regular Expressions.

gem install re\_template

or

> **[GitHub - masover/re\_template: Simple, Regular Expression powered template...](https://github.com/masover/re_template)**
>
> Simple, Regular Expression powered template engine. Intelligently handles HTML input. - GitHub - masover/re\_template: Simple, Regular Expression powered template engine. Intelligently handles HTML ...

No meaningful changes, or changelog. From the README:

# Features

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

# Usage

template = ReTemplate::Text.new  
template.expressions = {/{foo}/ =\> :foo, /{bar}/ =\> :bar}  
template.parse! ‘A {foo} is not a {bar}.’  
template.render :foo =\> ‘plant’, :bar =\> ‘rhinocerous’,  
:other\_expression =\>  
‘ignored’  
=\> ‘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  
change).  
Multiple calls to ‘render’ will work by design.  
It also works with HTML:

template = ReTemplate::Html.new  
template.add\_text\_expressions ‘’ =\> :foo, ‘|lang|’ =\> :lang  
template.parse! ‘

\<foo\> is not a valid |lang| tag.

’  
template.render :foo =\> ‘’, :lang =\> ‘HTML’  
=\> ‘

\<bar\> is not a valid HTML tag.

’

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.

# Motivation/Examples

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 \<user\>. 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  
HTML.

# CAVEATS

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  
know!