https://github.com/phplrt/phplrt

PHP Language Recognition Tool
https://github.com/phplrt/phplrt

ast combinator compiler grammar lexer library ll1 llk lookahead parser php phplrt recursive-descent-parser tool trace

Last synced: 3 months ago
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PHP Language Recognition Tool

• Host: GitHub
• URL: https://github.com/phplrt/phplrt
• Owner: phplrt
• License: mit
• Created: 2019-04-20T15:42:57.000Z (almost 6 years ago)
• Default Branch: 3.x
• Last Pushed: 2024-02-21T00:53:48.000Z (11 months ago)
• Last Synced: 2024-04-01T09:34:13.426Z (10 months ago)
• Topics: ast, combinator, compiler, grammar, lexer, library, ll1, llk, lookahead, parser, php, phplrt, recursive-descent-parser, tool, trace
• Language: PHP
• Homepage: https://phplrt.org
• Size: 6.63 MB
• Stars: 204
• Watchers: 9
• Forks: 6
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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## Introduction

The phplrt is a set of tools for programming languages recognition. The library 

provides lexer, parser, grammar compiler, library for working with errors, 

text analysis and so on.

## Installation

Phplrt is available as composer repository and can be 

installed using the following command in a root of your project:

```bash

$ composer require phplrt/phplrt

```

More detailed installation instructions [are here](https://phplrt.org/docs/installation).

## Documentation

- https://phplrt.org/

## Quick Start

First, we will create the grammar for our parser. 

> You can read more about the grammar syntax [here](https://phplrt.org/docs/compiler/grammar).

```php

load(<< (Operator() )* 

      ;

    #Operator

      : 

      | 

      | 

      | 

      ;

EBNF);

```

### Execution

In order to quickly check the performance of what has been written, you can use 

the simple `parse()` method. As a result, it will output the recognized abstract 

syntax tree along with the predefined AST classes which can be converted to their 

string representation.

```php

parse('2 + 2');

//

// Output:

//

// 

//     2

//     

//         +

//     

//     2

// 

//

```

### Compilation

After your grammar is ready and tested, it should be compiled. After that, 

you no longer need the `phplrt/compiler` dependency (see https://phplrt.org/docs/installation#runtime-only).

```php

file_put_contents(__DIR__ . '/grammar.php', (string)$compiler->build());

```

This file will contain your compiled data that can be used in your custom parser.

```php

use Phplrt\Lexer\Lexer;

use Phplrt\Parser\Parser;

use Phplrt\Parser\BuilderInterface;

use Phplrt\Parser\Context;

$data = require __DIR__ . '/grammar.php';

// Create Lexer from compiled data

$lexer = new Lexer($data['tokens']['default'], $data['skip']);

// Create Parser from compiled data

$parser = new Parser($lexer, $data['grammar'], [

    // Recognition will start from the specified rule

    Parser::CONFIG_INITIAL_RULE => $data['initial'],

    // Rules for the abstract syntax tree builder. 

    // In this case, we use the data found in the compiled grammar.

    Parser::CONFIG_AST_BUILDER => new class($data['reducers']) implements BuilderInterface {

        public function __construct(private array $reducers) {}

        public function build(Context $context, $result)

        {

            $state = $context->getState();

            return isset($this->reducers[$state])) 

                ? $this->reducers[$state]($context, $result)

                : $result

            ;

        }

    }

]);

// Now we are ready to parse any code using the compiled grammar

$parser->parse(' ..... ');

```