Symfony
sponsored by SensioLabs
Menu
  • About
  • Documentation
  • Screencasts
  • Cloud
  • Certification
  • Community
  • Businesses
  • News
  • Download
  1. Home
  2. Documentation
  3. Components
  4. Expression Language
  5. Dumping and Manipulating the AST of Expressions
  • Documentation
  • Book
  • Reference
  • Bundles
  • Cloud
Search by Algolia

Table of Contents

  • Dumping the AST
  • Manipulating the AST

Dumping and Manipulating the AST of Expressions

Edit this page

Warning: You are browsing the documentation for Symfony 4.1, which is no longer maintained.

Read the updated version of this page for Symfony 6.2 (the current stable version).

Dumping and Manipulating the AST of Expressions

Manipulating or inspecting the expressions created with the ExpressionLanguage component is difficult because they are plain strings. A better approach is to turn those expressions into an AST. In computer science, AST (Abstract Syntax Tree) is "a tree representation of the structure of source code written in a programming language". In Symfony, a ExpressionLanguage AST is a set of nodes that contain PHP classes representing the given expression.

Dumping the AST

Call the getNodes() method after parsing any expression to get its AST:

1
2
3
4
5
6
7
8
9
10
11
12
use Symfony\Component\ExpressionLanguage\ExpressionLanguage;

$ast = (new ExpressionLanguage())
    ->parse('1 + 2', [])
    ->getNodes()
;

// dump the AST nodes for inspection
var_dump($ast);

// dump the AST nodes as a string representation
$astAsString = $ast->dump();

Manipulating the AST

The nodes of the AST can also be dumped into a PHP array of nodes to allow manipulating them. Call the toArray() method to turn the AST into an array:

1
2
3
4
5
6
7
// ...

$astAsArray = (new ExpressionLanguage())
    ->parse('1 + 2', [])
    ->getNodes()
    ->toArray()
;
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.
We stand with Ukraine.
Version:
Symfony Code Performance Profiling

Symfony Code Performance Profiling

Check Code Performance in Dev, Test, Staging & Production

Check Code Performance in Dev, Test, Staging & Production

↓ Our footer now uses the colors of the Ukrainian flag because Symfony stands with the people of Ukraine.

Avatar of Jean-Guilhem Rouel, a Symfony contributor

Thanks Jean-Guilhem Rouel (@jean-gui) for being a Symfony contributor

2 commits • 90 lines changed

View all contributors that help us make Symfony

Become a Symfony contributor

Be an active part of the community and contribute ideas, code and bug fixes. Both experts and newcomers are welcome.

Learn how to contribute

Symfony™ is a trademark of Symfony SAS. All rights reserved.

  • What is Symfony?
    • Symfony at a Glance
    • Symfony Components
    • Case Studies
    • Symfony Releases
    • Security Policy
    • Logo & Screenshots
    • Trademark & Licenses
    • symfony1 Legacy
  • Learn Symfony
    • Symfony Docs
    • Symfony Book
    • Reference
    • Bundles
    • Best Practices
    • Training
    • eLearning Platform
    • Certification
  • Screencasts
    • Learn Symfony
    • Learn PHP
    • Learn JavaScript
    • Learn Drupal
    • Learn RESTful APIs
  • Community
    • SymfonyConnect
    • Support
    • How to be Involved
    • Code of Conduct
    • Events & Meetups
    • Projects using Symfony
    • Downloads Stats
    • Contributors
    • Backers
  • Blog
    • Events & Meetups
    • A week of symfony
    • Case studies
    • Cloud
    • Community
    • Conferences
    • Diversity
    • Documentation
    • Living on the edge
    • Releases
    • Security Advisories
    • SymfonyInsight
    • Twig
    • SensioLabs
  • Services
    • SensioLabs services
    • Train developers
    • Manage your project quality
    • Improve your project performance
    • Host Symfony projects
    Deployed on
Follow Symfony
Search by Algolia