A Simple PHP REPL

REPL.php

<?php

class REPL {
	private $stream;
	
	public function __construct($streamPath = 'php://stdin'){
		$this->stream = fopen($streamPath, 'r');
	}
	
	public function begin(){
		$scopeCount = 0;
		$parenCount = 0;
		$inQuotes = 0; // 1 for single, 2 for double
		$lines = '';
		$currentLine;
		$char;
		
		echo "PHP Repl - Written by Dominic Charley-Roy\n\n";
		
		while (true) {
			if ($scopeCount == 0 && $parenCount == 0 && $inQuotes == 0)
				echo "> ";
			else
				echo "  ";
			
			$currentLine = trim(fgets($this->stream));
			
			for ($i = 0; $i < strlen($currentLine); $i++){
				$char = $currentLine[$i];
				
				if ($inQuotes == 0 && $char == '{')
					$scopeCount++;
				else if ($char == '\'' && 
						($i == 0 || $currentLine[$i-1] != '\\') && 
						($inQuotes == 1 || $inQuotes == 0))
					$inQuotes = ($inQuotes == 0) ? 1 : 0;
				else if ($char == '"' && 
						($i == 0 || $currentLine[$i-1] != '\\') && 
						($inQuotes == 2 || $inQuotes == 0))
					$inQuotes = ($inQuotes == 0) ? 2 : 0;
				else if ($inQuotes == 0 && $char  == '(')
					$parenCount++;
				else if ($inQuotes == 0 && $char == '}'){
					if ($scopeCount == 0){
						echo "\nERROR: Unbalanced scope braces.";
						$parenCount = $parenCount = $inQuotes = 0;
						$currentLine = '';
						break;
					}
					
					$scopeCount--;
				} else if ($inQuotes == 0 && $char == ')'){ 
					if ($parenCount == 0){
						echo "\nERROR: Unbalanced parenthesis.";
						$parenCount = $parenCount = $inQuotes = 0;
						$currentLine = '';
						break;
					}
					
					$parenCount--;
				}
			}
			
			$lines.=$currentLine."\n";
			
			if ($scopeCount == 0 && $parenCount == 0 && $inQuotes == 0){
				if (strpos($lines, ';') === false)
					$return = eval('var_dump('.$lines.');');
				else
					$return = eval($lines.';');
				echo $return;
				$lines = '';
			}
		}
	}
	
	public function __destruct(){
		fclose($this->stream);
	}
}


$repl = new REPL();
$repl->begin();