openrat-cms

DslInterpreter.class.php (2811B)

---

 <?php
 
 namespace dsl\executor;
 
 use dsl\DslAstParser;
 use dsl\DslException;
 use dsl\DslLexer;
 use dsl\standard\Number;
 use dsl\standard\Script;
 use dsl\standard\StandardArray;
 use dsl\standard\StandardDate;
 use dsl\standard\StandardMath;
 use dsl\standard\StandardString;
 use dsl\standard\System;
 use dsl\standard\Write;
 
 class DslInterpreter
 {
 	/**
 	 * Execution context.
 	 *
 	 * @var array
 	 */
 	private $context = [];
 
 	/**
 	 * Holds a reference to the write()-Function for getting the output buffer after execution.
 	 * @var Write
 	 */
 	private $writer;
 	private $flags;
 
 	const FLAG_SHOW_ERROR  =  1;
 	const FLAG_SHOW_TRACE  =  2;
 	const FLAG_THROW_ERROR =  4;
 	const FLAG_DEBUG       =  8;
 	const FLAG_SECURE      = 16;
 
 	private static $secure = true;
 
 	public function __construct( $flags = self::FLAG_SHOW_ERROR + self::FLAG_SECURE )
 	{
 		$this->flags = $flags;
 
 		self::$secure = boolval($this->flags & self::FLAG_SECURE );
 
 		// Standard-Globals
 		$this->addContext( [
 
 			// Standard JS objects
 			'Math'   => new StandardMath(),
 			'Array'  => new StandardArray(),
 			'String' => new StandardString(),
 			'Number' => new Number(),
 			'Date'   => new StandardDate(),
 
 			// Custom Scriptbox objects
 			'System' => new System(),
 			'write'  => $this->writer = new Write(),
 		] );
 	}
 
 	/**
 	 * adds an external context to the interpreter environment.
 	 *
 	 * @param $context []
 	 */
 	public function addContext($context ) {
 		$this->context = array_merge( $this->context, $context );
 	}
 
 
 	/**
 	 * Parses and runs the DSL code.
 	 *
 	 * @param $code String Script-Code
 	 * @throws DslException
 	 * @return mixed value of last return statement (if any)
 	 */
 	public function runCode( $code ) {
 
 		// Step 1: Splitting the source code into tokens (the "Lexer")
 		$lexer = new DslLexer();
 		$token = $lexer->tokenize( $code );
 
 		// Step 2: Creating a syntax tree (abstract syntax tree, AST).
 		try {
 
 			$parser = new DslAstParser();
 			$parser->parse( $token );
 
 			//if   ( $this->flags & self::FLAG_DEBUG )
 			// it has no security impact, so lets do it always.
 				$this->addContext(
 					[ 'Script' => new Script( $token,$parser->rootStatement ) ]
 				);
 
 			// Step 3: Executing the syntax tree.
 			return $parser->execute( $this->context );
 		} catch ( \Exception $e ) {
 			if   ( $this->flags & self::FLAG_SHOW_ERROR ) {
 				if   ( $this->flags & self::FLAG_SHOW_TRACE )
 					$this->writer->buffer .= $e->__toString();
 				else
 					$this->writer->buffer .= $e->getMessage();
 			}
 			if   ( $this->flags & self::FLAG_THROW_ERROR )
 				throw $e;
 		}
 	}
 
 
 	/**
 	 * Gets the output which was written by the code.
 	 *
 	 * @return mixed
 	 */
 	public function getOutput() {
 
 		return $this->writer->buffer;
 	}
 
 	/**
 	 * @return bool
 	 */
 	public static function isSecure() {
 		return self::$secure;
 	}
 }