Encode/Decode EDN in PHP

A tool to encode/decode between EDN and PHP data structures.

Note

When converting from EDN to PHP the conversion is lossy as the richness of datatypes supported by EDN is not available in PHP. So a conversion from EDN to PHP and back to EDN would not lose you data, but it would lose type information.

Usage

The interface is via some static functions on the Edhen class. To decode an EDN element...

$element = Edhen::decode('(1 :foo [2])');

// array(1, ':foo', array(2))

If you have EDN with multiple elements, you can use decodeAll

$elements = Edhen::decodeAll(':foo :bar :baz');

// array(':foo', ':bar', ':baz')

Then for encoding use the encode function, passing it the data to encode...

$ednString = Edhen::encode(array(1, 2));

// '[1 2]'

Data Type Translations

When decoding EDN to PHP...

EDN	PHP
nil	null
true	true
false	false
strings	string
characters	string
symbols	string
keywords	string
integer	integer
floating-point	double
lists	array
vectors	array
maps	array
sets	array

Builtin Tags

EDN	PHP
inst	DateTime
uuid	string

When encoding PHP to EDN...

PHP	EDN
null	nil
boolean	boolean
integer	integer
double	float
array	vector
array (assoc)	hashmap
object	hashmap
resource	nil
callable	nil

The decision on if an array is to be converted to a vector or hashmap is done by checking its keys. If any of the keys are non-numeric then a hashmap is used.

EDN is generated as a single string, no pretty-printing is currently supported. Another tool should be used for this.

Custom Tag Handlers

To implement your own tag handlers, create a class which implements the Edhen\TagHandler interface and pass it in an array as the second argument to decode/decodeAll

$myHandler = new MyCustomTagHandler();

$element = Edhen::decode($edn, array($myHandler));

You can see an example in the tests.

Installation

Edhen can be installed via Composer.