clj-mustache

{{ mustache }} for Clojure.

Compliant with the Mustache spec.

Usage

Leiningen:

[org.clojars.majorcluster/clj-mustache "LAST RELEASE NUMBER"]

This is how you use clj-mustache:

(use 'clj-mustache.parser)
(render "Hello, {{name}}!" {:name "Felix"})

You can render a resource from the classpath like this:

(use 'clj-mustache.parser)
(render-resource "templates/hello.mustache" {:name "Michael"})

You can extract mustache variables like this:

(use 'clj-mustache.parser)
(extract-mustache-variables "<ul>\n{{#people}}\n    <li>{{name}}</li>\n{{/people}}\n</ul>")

Each function supports an optional third argument, containing partials (see below).

Examples

Variable replacement

Variables are tags enclosed by two curly brackets (mustaches) and will be replaced with the respective data.

Template:

Hello, {{person}}!

Data:

{:person "World"}

Output:

Hello, World!

Escaped output

The following characters will be replaced with HTML entities: &"<>. Tags that use three curly brackets or start with {{& will not be escaped.

Template:

Escaped: {{html}}
Unescaped: {{{html}}}
Unescaped: {{&html}}

Data:

{:html "<h1>Hello, World!</h1>"}

Output:

Escaped: <h1>Hello, World!</h1>
Unescaped: <h1>Hello, World!</h1>
Unescaped: <h1>Hello, World!</h1>

Sections

Sections start with a tag beginning with {{# and end with one beginning with {{/. Their content is only rendered if the data is either the boolean value true, a value or a non-empty list.

Template:

{{#greet}}Hello, World!{{/greet}}

Data:

{:greet true}

Output:

Hello, World!

In case of a list, the section's content is rendered for each element, and it can contain tags refering to the elements.

Template:

<ul>
{{#people}}
    <li>{{name}}</li>
{{/people}}
</ul>

Data:

{:people [{:name "Felix"} {:name "Jenny"}]}

Output:

<ul>
    <li>Felix</li>
    <li>Jenny</li>
</ul>

For single values, the section is rendered exactly once.

Template:

{{#greeting}}{{text}}!{{/greeting}}

Data:

{:greeting {:text "Hello, World"}}

Output:

Hello, World!

Inverted sections

Inverted sections start with a tag beginning with {{^ and end with one beginning with {{/. Their content is only rendered if the data is either the boolean value false or an empty list.

Template:

{{^ignore}}Hello, World!{{/ignore}}

Data:

{:ignore false}

Output:

Hello, World!

Comments

Comments are tags that begin with {{!. They will not be rendered.

Template:

<h2>Felix' section<h2>
{{! Look ma, I've written a section }}

Output:

<h2>Felix' section</h2>

Dotted names

Dotted names are a shorter and more convenient way of accessing nested variables or sections.

Template:

{{greeting.text}}

Data:

{:greeting {:text "Hello, World"}}

Output:

Hello, World

Implicit iterators

Implicit iterators allow you to iterate over a one dimensional list of elements.

Template:

<ul>
{{#names}}
    <li>{{.}}</li>
{{/names}}
</ul>

Data:

{:names ["Felix" "Jenny"]}

Output:

<ul>
    <li>Felix</li>
    <li>Jenny</li>
</ul>

Partials

Partials allow you to include other templates (e.g. from separate files).

Template:

Hello{{>names}}!

Data:

{:people [{:name "Felix"} {:name "Jenny"}]}

Partials:

{:names "{{#people}}, {{name}}{{/people}}"}

Output:

Hello, Felix, Jenny!

Set delimiters

You don't have to use mustaches, you can change the delimiters to anything you like.

Template:

{{=<% %>=}}
Hello, <%name%>!

Data:

{:name "Felix"}

Output:

Hello, Felix!

Lambdas

You can also call functions from templates.

Template:

{{hello}}
{{#greet}}Felix{{/greet}}

Data:

{:hello "Hello, World!"}
{:greet #(str "Hello, " %)}

Output:

Hello, World!
Hello, Felix!

Functions can also render the text given to them if they need to do something more complicated.

Template:

"{{#people}}Hi {{#upper}}{{name}}{{/upper}}{{/people}}"

Data:

{:people [{:name "Felix"}] 
 :upper (fn [text] 
          (fn [render-fn] 
            (clojure.string/upper-case (render-fn text))))}

Output:

Hello FELIX

Development

To run the spec tests, fetch them like this:

git submodule update --init

And run them against all supported Clojure versions:

lein all test

License

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA