PHP Parser Written in Go

PHP Parser written in Go

This project uses goyacc and golex libraries to parse PHP sources into AST . It can be used to write static analysis, refactoring, metrics, code style formatting tools.

Try it online: demo

Features:

• Fully support PHP 5 and PHP 7 syntax
• Abstract syntax tree (AST) representation
• Traversing AST
• Namespace resolver
• Able to parse syntax-invalid PHP files

Roadmap

• Pretty printer
• Control Flow Graph (CFG)
• PhpDocComment parser
• Stabilize api

Install

go get github.com/z7zmey/php-parser

CLI

php-parser [-php5 -noDump] <path> ...

Dump AST to stdout.

Example

package main

import (
	"fmt"
	"bytes"
	"os"

	"github.com/z7zmey/php-parser/php7"
	"github.com/z7zmey/php-parser/visitor"
)

func main() {
	src := bytes.NewBufferString(`<? echo "Hello world";`)

	parser := php7.NewParser(src, "example.php")
	parser.Parse()

	for _, e := range parser.GetErrors() {
		fmt.Println(e)
	}

	visitor := visitor.Dumper{
		Writer:    os.Stdout,
		Indent:    "",
		Comments:  parser.GetComments(),
		Positions: parser.GetPositions(),
	}

	rootNode := parser.GetRootNode()
	rootNode.Walk(visitor)
}

Namespace resolver

Namespace resolver is a visitor that resolves nodes fully qualified name and saves into map[node.Node]string structure

• For Class , Interface , Trait , Function , Constant nodes it saves name with current namespace.
• For Name , Relative , FullyQualified nodes it resolves use aliases and saves a fully qualified name.

Parsing syntax-invalid PHP files

If we try to parse $a$b; then the parser triggers error 'syntax error: unexpected T_VARIABLE'. Token $b is unexpected, but parser recovers parsing process and returns $b; statement to AST, because it is syntactically correct.

Pretty printer [work in progress]

nodes := &stmt.StmtList{
	Stmts: []node.Node{
		&stmt.Namespace{
			NamespaceName: &name.Name{
				Parts: []node.Node{
					&name.NamePart{Value: "Foo"},
				},
			},
		},
		&stmt.Class{
			Modifiers: []node.Node{
				&node.Identifier{Value: "abstract"},
			},
			ClassName: &name.Name{
				Parts: []node.Node{
					&name.NamePart{Value: "Bar"},
				},
			},
			Extends: &stmt.ClassExtends{
				ClassName: &name.Name{
					Parts: []node.Node{
						&name.NamePart{
							Value: "Baz"
						},
					},
				},
			},
			Stmts: []node.Node{
				&stmt.ClassMethod{
					Modifiers: []node.Node{
						&node.Identifier{Value: "public"},
					},
					MethodName: &node.Identifier{Value: "greet"},
					Stmt: &stmt.StmtList{
						Stmts: []node.Node{
							&stmt.Echo{
								Exprs: []node.Node{
									&scalar.String{Value: "'Hello world'"},
								},
							},
						},
					},
				},
			},
		},
	},
}

file := os.Stdout
p := printer.NewPrinter(file, "    ")
p.PrintFile(nodes)

It prints to stdout:

<?php
namespace Foo;
abstract class Bar extends Baz
{
	public function greet()
	{
		echo 'Hello world';
	}
}