Rust PHP Parser

A fast, fault-tolerant PHP parser written in Rust. Produces a full typed AST with source spans, recovers from syntax errors, and covers PHP 8.0–8.5 syntax.

Quick Start

use php_rs_parser::parse;

let arena = bumpalo::Bump::new();
let result = parse(&arena, "<?php echo 'Hello, world!';");

println!("{:#?}", result.program);

for err in &result.errors {
    println!("error at {:?}: {}", err.span(), err);
}

// Resolve byte offsets to line/column
let pos = result.source_map.offset_to_line_col(6);

API Reference

The three entry points you need for integration:

• parse() / parse_versioned() — main parser entry points in php-rs-parser; see crates/php-parser/src/lib.rs
• Visitor / ScopeVisitor — AST traversal traits in php-ast; see crates/php-ast/src/visitor.rs for the distinction between the two
• ParseError variants — see crates/php-parser/src/diagnostics.rs and docs/development/ERRORS.md for recovery behavior

Usage

Version-aware parsing

The parser targets PHP 8.5 by default. Use parse_versioned() to target an earlier version:

use php_rs_parser::{parse_versioned, PhpVersion};

let arena = bumpalo::Bump::new();
let result = parse_versioned(
    &arena,
    "<?php enum Status { case Active; }",
    PhpVersion::Php80,
);
// Enums require PHP 8.1 — a VersionTooLow diagnostic is emitted.
assert!(!result.errors.is_empty());

Supported versions: Php74, Php80, Php81, Php82, Php83, Php84, Php85.

Visitor API

Implement Visitor to walk the AST depth-first. Override only the node types you care about; the default implementations recurse into children automatically.

use php_ast::visitor::{Visitor, walk_expr};
use php_ast::ast::*;
use std::ops::ControlFlow;

struct VarCounter { count: usize }

impl<'arena, 'src> Visitor<'arena, 'src> for VarCounter {
    fn visit_expr(&mut self, expr: &Expr<'arena, 'src>) -> ControlFlow<()> {
        if matches!(&expr.kind, ExprKind::Variable(_)) {
            self.count += 1;
        }
        walk_expr(self, expr)
    }
}

Return ControlFlow::Break(()) to stop traversal early. Return ControlFlow::Continue(()) without calling walk_* to skip a subtree.

For scope-aware traversal (ScopeVisitor, ScopeWalker) and the PHPDoc parser, see docs/usage/VISITOR.md.

Pretty printer

let arena = bumpalo::Bump::new();
let result = php_rs_parser::parse(&arena, "<?php echo 1 + 2;");
let output = php_printer::pretty_print(&result.program);
// output == "echo 1 + 2;"

Use pretty_print_file to produce a complete file with a <?php\n\n prefix and trailing newline.

Architecture

Four crates, one workspace:

Crate	crates.io	Purpose
php-lexer		Hand-written tokenizer with handling for strings, heredoc/nowdoc, and inline HTML
php-ast		AST type definitions, Visitor trait, ScopeVisitor trait
php-rs-parser		Pratt-based recursive descent parser with panic-mode error recovery, PHPDoc parser, source map
php-printer		Pretty printer — converts an AST back to PHP source

Source flows through Lexer → Parser → arena-allocated AST nodes. The lexer is lazy (tokens produced on demand with peeking slots); the parser is Pratt-based recursive descent with panic-mode error recovery.

Performance

This parser is optimised for modern PHP applications with full typing (PHP 7.4+, 8.x). It delivers the fastest performance on Symfony, Laravel, and other typed codebases.

The fastest full-featured PHP parser. For detailed analysis see docs/performance/. For comparative benchmarks against other PHP parsers see php-parser-benchmark.

Contributing

See CONTRIBUTING.md for build instructions, testing, and contributor guides. Full documentation is in the docs/ directory.

Acknowledgements

Inspired by and indebted to nikic/PHP-Parser — test corpus fixtures were adapted from its test suite. Thanks to the PHP community contributors.

License

BSD 3-Clause