Pretty printing =============== Pretty printing is the process of converting a syntax tree back to PHP code. In its basic mode of operation the pretty printer provided by this library will print the AST using a certain predefined code style and will discard (nearly) all formatting of the original code. Because programmers tend to be rather picky about their code formatting, this mode of operation is not very suitable for refactoring code, but can be used for automatically generated code, which is usually only read for debugging purposes. Basic usage ----------- ```php $stmts = $parser->parse($code); // MODIFY $stmts here $prettyPrinter = new PhpParser\PrettyPrinter\Standard; $newCode = $prettyPrinter->prettyPrintFile(); ``` The pretty printer has three basic printing methods: `prettyPrint()`, `prettyPrintFile()` and `prettyPrintExpr()`. The one that is most commonly useful is `prettyPrintFile()`, which takes an array of statements and produces a full PHP file, including opening ` **Note:** This functionality is **experimental** and not yet complete. For automated code refactoring, migration and similar, you will usually only want to modify a small portion of the code and leave the remainder alone. The basic pretty printer is not suitable for this, because it will also reformat parts of the code, which have not been modified. Since PHP-Parser 4.0 an experimental formatting-preserving pretty-printing mode is available, which attempts to preserve the formatting of code, those AST nodes have not changed, and only reformat code which has been modified or newly inserted. Use of the formatting-preservation functionality currently requires some additional preparatory steps: ```php use PhpParser\{Lexer, NodeTraverser, NodeVisitor, Parser, PrettyPrinter}; $lexer = new Lexer\Emulative([ 'usedAttributes' => [ 'comments', 'startLine', 'endLine', 'startTokenPos', 'endTokenPos', ], ]); $parser = new Parser\Php7($lexer); $traverser = new NodeTraverser(); $traverser->addVisitor(new NodeVisitor\CloningVisitor()); $printer = new PrettyPrinter\Standard(); $oldStmts = $parser->parse($code); $oldTokens = $lexer->getTokens(); $newStmts = $traverser->traverse($oldStmts); // MODIFY $newStmts HERE $newCode = $printer->printFormatPreserving($newStmts, $oldStmts, $oldTokens); ``` This functionality is experimental and not yet fully implemented. It should not provide incorrect code, but it may sometimes reformat more code than necessary. Open issues are tracked in [issue #344][https://github.com/nikic/PHP-Parser/issues/344]. If you encounter problems while using this functionality, please open an issue, so we know what to prioritize.