PHPClosure2SQL

prototype.php

<?php

class Collection
{
	private $items = array();



	function add($item)
    {
    	$this->items[] = $item;
    }



	function select($closure)
    {
    	$selected = array();
		foreach ($this->items as $item) {
			if ($closure($item)) {
				$selected[] = $item;
			}
		}
		return $selected;
    }
}


class DatabaseCollection
{
	function select($closure)
    {
		echo $this->buildSql($closure), "\n";
    }



    function buildSql($closure)
    {
    	$reflection = new ReflectionFunction($closure);
		$parameters = $reflection->getParameters();
		$staticVars = $reflection->getStaticVariables();

		$table = reset($parameters)->name;
		$sql = "SELECT *\nFROM " . $table;
		$where = '';
		$skip = TRUE;
		$expectProperty = FALSE;
		$join = NULL;

		foreach (token_get_all('<?php ' . $this->getSourceOf($reflection)) as $token) {
			if (is_string($token)) {
				$token = array($token, $token, NULL);
			}

			//echo @token_name($token[0]), ' ', $token[1], "\n";

			if ($skip) {
				switch ($token[0]) {
				case T_RETURN:
					$skip = FALSE;
					break;
				}

			} else {
				switch ($token[0]) {
				case T_VARIABLE:
					$var = substr($token[1], 1);
					$where .= isset($staticVars[$var]) ? '"' . $staticVars[$var] . '"' : $var;
					break;
				case T_OBJECT_OPERATOR:
					if ($join) {
						$sql .= "\nINNER JOIN $join ON $join.id = $table.{$join}_id ";
					}
					$where .= '.';
					break;
				case T_IS_IDENTICAL:
					$where .= '=';
					break;
				case '}':
					break 2;
				case ';':
					break;
				case T_STRING:
					if ($expectProperty) {
						$join = $token[1];
					}
				default:
					$where .= $token[1];
					break;
				}

				$expectProperty = $token[0] === T_OBJECT_OPERATOR;
			}
		}

		return $sql . "\nWHERE " . trim($where);
    }



    function getSourceOf($reflection)
    {
        $f = fopen($reflection->getFileName(), 'r');
		$source = '';
		for ($i = 1; $i <= $reflection->getEndLine(); $i++) {
			$line = fgets($f);
			if ($i >= $reflection->getStartLine()) {
				$source .= $line;
			}
		}
		return $source;
    }
}



$pages = new DatabaseCollection;

$catName = 'news';
$pages->select(function($page) use ($catName)
{
	return $page->category->name === $catName;
});

/* Output:
SELECT *
FROM page
INNER JOIN category ON category.id = page.category_id
WHERE page.category.name = "news"
*/