Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
a selector-based (à la CSS) templating and transformation system for Clojure
Clojure
branch: lazy

This branch is even with cgrand:lazy

Fetching latest commit…

Cannot retrieve the latest commit at this time

Failed to load latest commit information.
lib
src/net/cgrand
README.textile
epl-v10.html

README.textile

Enlive

Enlive is a selector-based (à la CSS) templating library for Clojure.

An Enlive template has two parts: a HTML file and a deftemplate form
somewhere in a clj file.

Syntax

A deftemplate form looks like this:

(deftemplate template-name “path/to/the/resource/html/file.html” [regular function & arguments] ; once compiled a template is a fn returning a seq of strings selector1 action1 selector2 action2 … … selectorN actionN)

How does it work?

Overview

  1. The HTML file is parsed into a clojure.xml tree,
  2. nodes matched by selectors are replaced by the result of applying the
    associated action to them (this result may be some clojure code — we are in
    a macro),
  3. the resulting tree is compiled into a form like this one
    '(list "<a><big><constant><string>" (some code) "</string>" (some other code) "</constant></big></a>").

Selectors

Selectors are states in an infinite state machine. step-selector is the
transition function. A selector is said to be successful (accept state) if
(action selector) is non-nil.

When then selector is successful, its action is applied to the current node
and returns a transformed node (a mix of a clojure.xml tree and clojure code).

Template-macros

When a subtree is selected it is passed to the action part of the rule which
is either a direct or indirect call to a template-macro or regular clojure
code.

A template macro is defined using deftemplate-macro. The first parameter of
a template-macro is the selected xml subtree. Note that you must not pass this
parameter when you call the template-macro: Enlive takes care of that.

A template-macro must return a transformed node (a mix of a clojure.xml tree
and clojure code).

Flattening

Each transformed node is flattened: it is first turned into nested seqs of
strings and clojure code, then these nested seqs are flattened and runs of
strings are merged.

Clojure code

Return value

When you put clojure code into a template (that is into the resulting
transformed node) it must either return a string or a seq of strings or a seq
of seq of strings and strings etc. As long as
(remove seq? (tree-seq seq? seq (list returned-value))) yields a seq of
strings that’s ok.

So, yes, nil is a legit return value and it’s pretty useful to remove the
selected node. Hence the idiom (when test ~(show)).

Calling a template-macro

To call a template macro when you are inside some clojure code, you have to
use unquote: (when test ~(show)). Note that you must not pass the selected
node to the template-macro (here show).

Something went wrong with that request. Please try again.