Handlebars (template System)

Mustache is a web template system with implementations available for ActionScript, C++, Clojure, CoffeeScript, ColdFusion, Common Lisp, Crystal, D, Dart, Delphi, Elixir, Erlang, Fantom, Go, Haskell, Io, Java, JavaScript, Julia, Lua, .NET, Objective-C, OCaml, Perl, PHP, Pharo, Python, R, Racket, Raku, Ruby, Rust, Scala, Smalltalk, Swift, Tcl, CFEngine, and XQuery.

Mustache is described as a ''logic-less'' system because it lacks any explicit control flow statements, like if and else conditionals or for loops; however, both looping and conditional evaluation can be achieved using section tags processing lists and anonymous functions (lambdas).

It is named "Mustache" because of heavy use of braces, , that resemble a sideways moustache.

Mustache is used mainly for mobile and web applications.

History and principles

''Mustache-1'' was inspired by ctemplate and et, and began as a GitHub distribution at the end of 2009. A first version of the template engine was implemented with Ruby, running YAML template texts. The (preserved) main principles were:
* ''Logic-less'': no explicit control flow statements, all control driven by data.
* Strong ''separation of concerns: logic from presentation'': it is impossible to embed application logic in the templates.

The input data can be a class so that input data can be characterized as an model–view–controller (MVC) view. The Mustache ''template'' does nothing but reference methods in the (input data) ''view''. All the logic, decisions, and code is contained in this ''view'', and all the markup (ex. output XML) is contained in the ''template''. In an model–view–presenter (MVP) context: input data is from MVP-''presenter'', and the Mustache template is the MVP-''view''.

Examples

The simplest template:

Hello

Template with section tag:

Some text

Here, when x is a Boolean value then the section tag acts like an ''if'' conditional, but when x is an array then it acts like a foreach loop.

Template that is un-escaped:

Here, if body contains HTML, it won't be escaped.

Technical details

Syntax highlighting is available in Atom, Coda, Emacs, TextMate, Vim and Visual Studio Code.

The Mustache templates support is built into many web application frameworks (ex. CakePHP). The support in JavaScript includes both client-side programming with many JavaScript libraries and Ajax frameworks such as jQuery, Dojo and YUI, as well as server-side JavaScript using Node.js and CommonJS.

Specification and implementations

There are many ''Mustache Engine'' implementations available, and all of them meet a common formal specification (see external links), that for final users results in the common syntax.

As of March 2011, the last SPEC_VERSION was 1.1.2.

All ''Mustache Engines'', in the v1.X architecture, have a ''render'' method, a ''Mustache_Compiler'' class and a ''Parser'' class.

Variations and derivatives

Mustache inspired numerous JavaScript template libraries which forked from the original simplicity to add certain functionality or use.

Handlebars

Handlebars.js is self-described as:

Handlebars differs from its predecessor in that, within ''Block Expressions'' (similar to sections in Mustache), ''Helpers'' allow custom function through explicit user-written code for that block.

See also

* JavaScript framework
* JavaScript library

References

External links

*
*

Mustache syntax

Mustache spec

{{JS templating

Free computer libraries
Template engines