8000 feature #7831 Added an article about ExpressionLanguage AST (javiereg… · symfony/symfony-docs@cf274b7 · GitHub
[go: up one dir, main page]
Skip to content
  • Insights

    • Commit cf274b7

    Browse files
    xabbuhxabbuh
    committed
    feature #7831 Added an article about ExpressionLanguage AST (javiereguiluz)
    This PR was squashed before being merged into the 3.2 branch (closes #7831). Discussion ---------- Added an article about ExpressionLanguage AST I need ExpressionLanguage experts to review the first part of the new article and to give me clues about how to write the second part. Thanks! Let's ping some experts in this: @lyrixx and @nicolas-grekas. This fixes #7185. Commits ------- a91a590 Added an article about ExpressionLanguage AST
    2 parents 412fe84 + a91a590 commit cf274b7

    File tree

    2 files changed

    +55
    -0
    lines changed

    2 files changed

    +55
    -0
    lines changed

    ‎components/expression_language.rst‎

    Lines changed: 6 additions & 0 deletions
    Original file line numberDiff line numberDiff line change
    @@ -112,6 +112,12 @@ Caching
    112112
    The component provides some different caching strategies, read more about them
    113113
    in :doc:`/components/expression_language/caching`.
    114114

    115+
    AST Dumping and Editing
    116+
    -----------------------
    117+
    118+
    The AST (*Abstract Syntax Tree*) of expressions can be dumped and manipulated
    119+
    as explained in :doc:`/components/expression_language/ast`.
    120+
    115121
    Learn More
    116122
    ----------
    117123

    ‎components/expression_language/ast.rst‎

    Lines changed: 49 additions & 0 deletions
    Original file line numberDiff line numberDiff line change
    @@ -0,0 +1,49 @@
    1+
    .. index::
    2+
    single: AST; ExpressionLanguage
    3+
    single: AST; Abstract Syntax Tree
    4+
    5+
    Dumping and Manipulating the AST of Expressions
    6+
    ===============================================
    7+
    8+
    Manipulating or inspecting the expressions created with the ExpressionLanguage
    9+
    component is difficult because they are plain strings. A better approach is to
    10+
    turn those expressions into an AST. In computer science, `AST`_ (*Abstract
    11+
    Syntax Tree*) is *"a tree representation of the structure of source code written
    12+
    in a programming language"*. In Symfony, a ExpressionLanguage AST is a set of
    13+
    nodes that contain PHP classes representing the given expression.
    14+
    15+
    Dumping the AST
    16+
    ---------------
    17+
    18+
    Call the :method:`Symfony\\Component\\ExpressionLanguage\\ExpressionLanguage::getNodes`
    19+
    method after parsing any expression to get its AST::
    20+
    21+
    use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
    22+
    23+
    $ast = (new ExpressionLanguage())
    24+
    ->parse('1 + 2')
    25+
    ->getNodes()
    26+
    ;
    27+
    28+
    // dump the AST nodes for inspection
    29+
    var_dump($ast);
    30+
    31+
    // dump the AST nodes as a string representation
    32+
    $astAsString = $ast->dump();
    33+
    34+
    Manipulating the AST
    35+
    --------------------
    36+
    37+
    The nodes of the AST can also be dumped into a PHP array of nodes to allow
    38+
    manipulating them. Call the :method:`Symfony\\Component\\ExpressionLanguage\\ExpressionLanguage::toArray`
    39+
    method to turn the AST into an array::
    40+
    41+
    // ...
    42+
    43+
    $astAsArray = (new ExpressionLanguage())
    44+
    ->parse('1 + 2')
    45+
    ->getNodes()
    46+
    ->toArray()
    47+
    ;
    48+
    49+
    .. _`AST`: https://en.wikipedia.org/wiki/Abstract_syntax_tree

    0 commit comments

    Comments
     (0)
    0