Dumping and Manipulating the AST of ExpressionsEdit this page
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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:
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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:
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// ... $astAsArray = (new ExpressionLanguage()) ->parse('1 + 2', ) ->getNodes() ->toArray() ;