Template engine (web)

This article is part of the Web Template Systems series.
Web template system Web template Template engine

A (web) template engine is software that is designed to process web templates and content information to produce output web documents. It runs in the context of a template system.

1 Types
2 Typical features
3 Example
4 Benefits
5 Comparison
6 Notes
7 See also
8 External links

Types

Template engine is ordinarily included as a part of a web template system or application framework, and may be used also as preprocessor, filter, or template processor. Currently, template processing software is most frequently used in the context of development for the web.

XSLT is a template processing model designed by W3C. It is designed primarily for transformations on XML data (into web documents or other output).

Programming languages such as Perl, Ruby, C, and Java support template processing either natively, or through add-on libraries and modules. JavaServer Pages (JSP), PHP, and Active Server Pages (ASP with VBScript, JScript or other languages) are examples, themselves, of web template engines.

Typical features

Template engines typically include features common to most high-level programming languages, with an emphasis on features for processing plain text.

Such features include:

variables and functions
text replacement
file inclusion (or transclusion)
conditional evaluation and loops

Example

The accompanying illustration depicts a simplified processing model for a typical web template engine. The template engine produces a web page by processing the web template source file along with data from a relational database. The template engine replaces variables with specific values. In the illustration, substitution of $X by the database content (in page 01 "Mother", on page 02 "World").

A web template might look like this:

<html>
   <h1>Hello {$X}</h1>
</html>

With additional template source code ...

templateAssign ('X', 'World');

... or, when specifying the relational database context:

$data[01]='Mother';  $data[02]='World';
templateAssign('X', $data[$i]);

Benefits

Benefits of using template engines include:

Encouraging organization of source code into operationally-distinct layers (see e.g., MVC)
Enhancing productivity by reducing unnecessary reproduction of effort
Enhancing teamwork by allowing separation of work based on skill-set (e.g., artistic vs. technical)

Comparison

The following table lists the various template engines discussed on Wikipedia and a brief rundown of their features. The content here is a work-in-progress.

Engine (Implementation)	Languages	License	Platform	Variables	Functions	Includes	Conditional Inclusion	Looping	Evaluation (Language)	Assignment	Errors & Exceptions	i18n	Natural Templates
Apache Velocity	Java, C#	Apache License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
ASP.net (Microsoft)	C#, VB.net	Proprietary	Microsoft Windows	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
ASP.net (Mono)	C#	GNU LGPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
AutoGen	C	GPL license	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes
Beilpuz	PHP 5	GNU LGPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes
Casper	Java, JavaScript	MIT	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
CheetahTemplate	Python	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Chip Template Engine	PHP, Perl	open-source?	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	Yes	No
CodeCharge Studio	Classic ASP, C#, VB.net, PHP, Perl, Java/JSP, ColdFusion	Proprietary	Microsoft Windows	Yes	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes
ColdFusion	CFML, CFScript	Proprietary	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Cottle	C#	BSD License	Microsoft Windows	Yes	Yes	Yes	Yes	Yes	No	Yes	No	No	No
csharptemplates	C#	New BSD	.NET	Yes	No	No	No	No	No	No	No
CTPP	C, C++, Perl, PHP, Python	BSD-like	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	No	Yes
dbPager	C++	GNU GPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Deihro TemplateEngine	PHP	open-source	Cross-Platform	Yes	Yes	indirect	No	No	No	No	No
Dermis	Classic ASP	MIT License	Microsoft Windows	Yes	No	Yes	No	Yes	No	Yes	No
Django	Python	BSD-like	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Djolt-objc	Objective-C	Apache License	iPhone/MacOS	Yes	No	No	No	Yes	No	No	No
Dwoo	PHP 5	BSD License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	Yes
Dylan Server Pages	Dylan language	unknown	unknown	Yes	Yes	Yes	Yes	No?	No	No	No
Engine (Implementation)	Languages	License	Platform	Variables	Functions	Includes	Conditional Inclusion	Looping	Evaluation (Language)	Assignment	Errors & Exceptions	i18n	Natural Templates
eRuby	Ruby	GPL / Ruby License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Evoque Templating	Python, Py3K	AFL v3.0	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Python)	No	Yes
FastTemplate	PHP	Artistic License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	Yes	No
FreeMarker	Java	BSD-like	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Genshi (templating language)	Python	BSD-like	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Python)	Yes	Yes	Yes
Google-ctemplate	C++	BSD License	Cross-Platform	Yes	No	Yes	Yes	Yes	No	No	No
Grantlee Template System	C++/Qt	LGPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
GvTags	Groovy	Apache License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Groovy)	Yes	No
H2o	PHP, Ruby	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes
HAH	PHP	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	No
Haml	Ruby, PHP (WIP)	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Ruby)	Yes	Yes
Hamlets	Java	BSD	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes
Hyperkit PHP/XML Template Engine	PHP, XML	open-source	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes			Yes
Jasper framework	Perl, PHP, C#, Java	open-source?	Cross-Platform	Yes	No	No	No	No	No	No	No
JavaServer Pages	Java	Proprietary	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Jenner	JavaScript	LGPL	In-Browser	Yes	Yes	No	No	Yes	Yes	Yes (if allowed by hosting application)	Yes
jin-template	Java, PHP	LGPL	Cross-Platform	Yes	No	No	No	No	No	Yes	No
Jinja	Python	BSD	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Python)	Yes	No
Jinja2	Python	BSD	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Python)	Yes	Yes
JScore	PHP + JS	Proprietary	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
JSP Weaver	Java	Proprietary	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Engine (Implementation)	Languages	License	Platform	Variables	Functions	Includes	Conditional Inclusion	Looping	Evaluation (Language)	Assignment	Errors & Exceptions	i18n	Natural Templates
Kalahari	Python	BSD-like	Cross-Platform	Yes	Yes	Through inheritance	No	Yes	No	Yes	Yes
Kid (templating language)	Python	MIT	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Python)	Yes	Yes
Mako	Python	MIT	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Python)	Yes	Yes
Mars-Templater	PHP 5	MIT License	Cross-Platform	Yes	No	No	Yes	Yes	No	No	No
MiniTemplator	PHP, Java, VB.net	GNU LGPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	No	No?
nTPL	node.js, JavaScript	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Obyx	Obyx	GNU GPL	Unix/Mac OS X	Yes	Yes	Yes	Yes	Yes	Yes (Obyx)	Yes	Yes	Yes	Yes
Open Power Template	PHP 5	BSD-like	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	Yes
Outline	PHP 5	open-source	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	Yes?
PHAML	PHP	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	Yes?
Phammable	PHP 5	GNU GPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	Yes
PHP	PHP	PHP License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
PURE Unobtrusive Rendering Engine	Javascript	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes		Yes
pyratemp	Python	MIT	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Python)	Yes	No
QueryTemplates	PHP 5, JavaScript	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
RainTPL	PHP	GNU LGPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	Yes
Scalate	Scala, Java	Apache License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Scala)	Yes	Yes
Simplate	PHP	GPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes		Yes
Smarty	PHP	GNU LGPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	Yes?	Yes
StringTemplate	Java (native), Python, C#	BSD^[1]	Cross-Platform	Yes	No	Yes	Yes	Yes	No	No	No
SUIT Framework	PHP, Python	GNU LGPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Engine (Implementation)	Languages	License	Platform	Variables	Functions	Includes	Conditional Inclusion	Looping	Evaluation (Language)	Assignment	Errors & Exceptions	i18n	Natural Templates
/ Talus' TPL
Template Attribute Language	Python, PHP 5	open-source	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
ATal	PHP 5.3	open-source	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Template Blocks	PHP 5	GNU GPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	Yes	Yes?
Template Toolkit	Perl, Python	open-source	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (Perl)	Yes	Yes
Thymeleaf	Java	Apache License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
TinyButStrong	PHP	GNU LGPL	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Toupl	Any with OOP and String class support	Apache License	Cross-Platform	Yes^[2]	Yes^[2]	Yes^[2]	Yes^[2]	Yes^[2]	Yes^[2]	Yes^[2]	Yes^[2]
Twig	PHP	BSD	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes
uBook Template	PHP	GPL	Cross-Platform	Yes	No	No	No	Yes	No	Yes	Yes	No	Yes
Vemplator	PHP	MIT License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes (PHP)	No	No
vlibTemplate	PHP	Artistic License	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	No	No
WebMacro	Java	open-source?	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Younicycle	PHP 5, JavaScript, ActionScript	Proprietary	Cross-Platform	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes
ZeniTPL	PHP	new BSD	Cross-Platform	Yes	No	No	No	Yes	No	Yes	No
BabaJS	Javascript	Open Source	Cross-Platform	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	No	No
Engine (Implementation)	Languages	License	Platform	Variables	Functions	Includes	Conditional Inclusion	Looping	Evaluation (Language)	Assignment	Errors & Exceptions	i18n	Natural Templates

LEGEND:

Engine (Implementation)= engine name
Languages= implemention language of the engine (not the template script language)
License= Software license agreement
Platform= Computing platform
Variables= script language power to use variables
Functions= script language power to use functions
Includes= script language power include external files
Conditional Inclusion= script language power to conditional includes
Looping= script language power to do loops (for, while) or recursion
Evaluation (Language)= script language power to do "eval command" (to the implemention language)
Assignment= set names and references to sub-templates (?)
Errors & Exceptions= engine output script errors.
i18n= Internationalization and localization feature
Natural Templates= the template can be a document as valid as the final result, the engine syntax doesn't break the document's structure

Notes

^ http://www.stringtemplate.org/license.html
^ ^a ^b ^c ^d ^e ^f ^g ^h Toupl is only compiler.Feature depend from target language