errant/tacit

<?php
namespace Tacit\Compiler;
/**
 * Tac Compiler
 *
 * @author Tom Morton
 */
class Tac {

    public static function run($tokens, $grammar)
    {
        $bytestream = array();
        $vectors = array();
        $targets = array();
        $i = 0;

        foreach($tokens as $command) {
            if(!isset($command['T_CMD'])) {
                throw new \Exception('Compiler Error: No command token');
            }
            if(!isset($grammar[$command['T_CMD']])) {
                throw new \Exception('Compiler Error: Missing Grammar - ' . $command['T_CMD']);
            }
            // Inc counter
            $i++;
            // Get instruction
            list($byte, $instruction) = $grammar[$command['T_CMD']];
            // 
            $vectors[$i] = count($bytestream);
            $result = $instruction->compile($bytestream, $byte, $command);
            if(is_array($result)) {
                list($target, $uuid) = $result;
                $targets[$uuid] = $i + $target;
            }
        }
        // resolve targets
        $bytestream = array_map(function($byte) use($vectors, $targets) { return array_key_exists($byte,$targets) ? $vectors[$targets[$byte]] - 1 : $byte; }, $bytestream);
        return $bytestream;
    }
}