File dsl/executor/DslInterpreter.class.php

Last commit: Tue Jul 19 00:10:39 2022 +0200	Jan Dankert	Fetched from upstream.


     1 <?php
     2 
     3 namespace dsl\executor;
     4 
     5 use dsl\DslAstParser;
     6 use dsl\DslException;
     7 use dsl\DslLexer;
     8 use dsl\standard\ArrayWrapper;
     9 use dsl\standard\NumberInstance;
    10 use dsl\standard\NumberWrapper;
    11 use dsl\standard\Script;
    12 use dsl\standard\ArrayInstance;
    13 use dsl\standard\DateWrapper;
    14 use dsl\standard\MathWrapper;
    15 use dsl\standard\StringInstance;
    16 use dsl\standard\StringWrapper;
    17 use dsl\standard\System;
    18 use dsl\standard\Writer;
    19 use dsl\standard\WriteWrapper;
    20 
    21 class DslInterpreter
    22 {
    23 	/**
    24 	 * Execution context.
    25 	 *
    26 	 * @var array
    27 	 */
    28 	private $context = [];
    29 
    30 	/**
    31 	 * Holds a reference to the write()-Function for getting the output buffer after execution.
    32 	 * @var Writer
    33 	 */
    34 	private $writer;
    35 	private $flags;
    36 
    37 	const FLAG_SHOW_ERROR  =  1;
    38 	const FLAG_SHOW_TRACE  =  2;
    39 	const FLAG_THROW_ERROR =  4;
    40 	const FLAG_DEBUG       =  8;
    41 	const FLAG_SECURE      = 16;
    42 
    43 	private static $secure = true;
    44 
    45 	public function __construct( $flags = self::FLAG_SHOW_ERROR + self::FLAG_SECURE )
    46 	{
    47 		$this->flags = $flags;
    48 
    49 		self::$secure = boolval($this->flags & self::FLAG_SECURE );
    50 
    51 		// Standard-Globals
    52 		$this->addContext( [
    53 
    54 			// Standard JS objects
    55 			'Math'   => new MathWrapper(),
    56 			'Array'  => new ArrayWrapper(),
    57 			'String' => new StringWrapper(),
    58 			'Number' => new NumberWrapper(),
    59 			'Date'   => new DateWrapper(),
    60 
    61 			// Custom Scriptbox objects
    62 			'System'  => new System(),
    63 			'write'   => $this->writer = new Writer(),
    64 			'writeln' => new WriteWrapper( $this->writer,"\n" ),
    65 			'print'   => new WriteWrapper( $this->writer,'' ),
    66 			'println' => new WriteWrapper( $this->writer,"\n" ),
    67 		] );
    68 	}
    69 
    70 	/**
    71 	 * adds an external context to the interpreter environment.
    72 	 *
    73 	 * @param $context []
    74 	 */
    75 	public function addContext($context ) {
    76 		$this->context = array_merge( $this->context, $context );
    77 	}
    78 
    79 
    80 	/**
    81 	 * Parses and runs the DSL code.
    82 	 *
    83 	 * @param $code String Script-Code
    84 	 * @throws DslException
    85 	 * @return mixed value of last return statement (if any)
    86 	 */
    87 	public function runCode( $code ) {
    88 
    89 		// Step 1: Splitting the source code into tokens (the "Lexer")
    90 		$lexer = new DslLexer();
    91 		$token = $lexer->tokenize( $code );
    92 
    93 		// Step 2: Creating a syntax tree (abstract syntax tree, AST).
    94 		try {
    95 
    96 			$parser = new DslAstParser();
    97 			$parser->parse( $token );
    98 
    99 			//if   ( $this->flags & self::FLAG_DEBUG )
   100 			// it has no security impact, so lets do it always.
   101 				$this->addContext(
   102 					[ 'Script' => new Script( $token,$parser->rootStatement ) ]
   103 				);
   104 
   105 			// Step 3: Executing the syntax tree.
   106 			return $parser->execute( $this->context );
   107 		} catch ( \Exception $e ) {
   108 			if   ( $this->flags & self::FLAG_SHOW_ERROR ) {
   109 				if   ( $this->flags & self::FLAG_SHOW_TRACE )
   110 					$this->writer->buffer .= $e->__toString();
   111 				else
   112 					$this->writer->buffer .= $e->getMessage();
   113 			}
   114 			if   ( $this->flags & self::FLAG_THROW_ERROR )
   115 				throw $e;
   116 		}
   117 	}
   118 
   119 
   120 	/**
   121 	 * Gets the output which was written by the code.
   122 	 *
   123 	 * @return mixed
   124 	 */
   125 	public function getOutput() {
   126 
   127 		return $this->writer->buffer;
   128 	}
   129 
   130 	/**
   131 	 * @return bool
   132 	 */
   133 	public static function isSecure() {
   134 		return self::$secure;
   135 	}
   136 }



Download dsl/executor/DslInterpreter.class.php


History
Tue, 19 Jul 2022 00:10:39 +0200	Jan Dankert	Fetched from upstream.
Mon, 27 Jun 2022 00:41:50 +0200	Jan Dankert	Fetched from upstream.
Sun, 26 Jun 2022 15:47:05 +0200	Jan Dankert	Fetched from upstream.
Mon, 6 Jun 2022 14:06:46 +0200	Jan Dankert	First commit after fetching from upstream repo.