FIQL Parser for PHP

Parse FIQL (feed item query language) expressions in PHP. The parser creates a syntax tree from a string expression in the Feed Item Query Language (

Build Status

Checkout the code

Note that this library is not yet stable enough for production usage. If you find a bug, please help by creating an issue on github.


This library currently does not use any third party dependencies. A PHP version >= 5.4 is required. For testing, phpspec is used.

Basic Usage

// autoloading is psr-4 compliant, so we can use composer
require 'vendor/autoload.php';

// initialize scanner and parser
$scanner = new \Ckr\Fiql\Scanner();
$parser = new \Ckr\Fiql\Parser($scanner);

// parse expression to a syntax tree
$syntaxTree = $parser->parse('field==value,second=lt=val;requiredField');

// example visitor usage
$visitor = new \Ckr\Fiql\Visitor\Printer();

echo 'The syntax tree visualized:' . PHP_EOL;
echo $visitor->getText();
echo PHP_EOL;

Syntax Tree

The syntax tree is composed of nodes implementing \Ckr\Fiql\Tree\Node.


You can implement a custom visitor class (implementing \Ckr\Fiql\Tree\Visitor) to process the syntax tree for your purposes, e.g. to check for matching feeds items. This library provides only one visitor, \Ckr\Fiql\Visitor\Printer, which is mainly used to visualize and compare syntax trees.


  • FIQL definition:
  • FIQL parser python: