readLangRef() to accept complex language strings

ToxgExpression.php

	protected function readLangRef()
	{
		// It looks like this: #xyz.abc[$mno][nilla].$rpg
		// Which means:
		//   x.y.z = x [ y ] [ z ]
		//   x[y.z] = x [ y [ z ] ] 
		//   x[y][z] = x [ y ] [ z ]
		//   x[y[z]] = x [ y [ z ] ]
		//
		// When we hit a ., the next item is surrounded by brackets.
		// When we hit a [, the next item has a [ before it.
		// When we hit a ], there is no item, but just a ].

		if ($this->data_pos >= $this->data_len - 1 || $this->data[$this->data_pos + 1] === ':' || $this->data[$this->data_pos + 1] === '}')
			$this->toss('expression_lang_name_empty');

		$brackets = 0;
		$key = true;

		while ($this->data_pos < $this->data_len)
		{
			$next = $this->firstPosOf(array('[', '.', ']', '}', ':'), 1);
			if ($next === false)
				$next = $this->data_len;

			$c = $this->data[$this->data_pos];
			$this->data_pos++;

			switch ($c)
			{
			case '#':
				$name = $this->eatUntil($next);
				if ($name === '')
					$this->toss('expression_lang_name_empty');

				$this->built[] = self::$lang_function . '(array(\'' . $name . '\'';
				break;

			case '.':
				if ($key)
				{
					$this->built[] = ',';
					$this->readVarPart($next, true);
				}
				else
				{
					$this->built[] = '[';
					$this->readVarPart($next, true);
					$this->built[] = ']';
				}
				break;

			case '[':
				if ($key)
				{
					$this->built[] = ',';
					$this->eatWhite();
					$this->readVarPart($next, false);
					$this->eatWhite();
				}
				else
				{
					$this->built[] = '[';
					$this->eatWhite();
					$this->readVarPart($next, false);
					$this->eatWhite();
				}

				$brackets++;
				break;

			case ']':
				// Ah, hit the end, jump out.  Must be a nested one.
				if ($brackets <= 0)
				{
					$this->data_pos--;
					break 2;
				}

				if (!$key)
					$this->built[] = ']';

				$brackets--;
				break;

			// All done - but don't skip it, our caller doesn't expect that.
			case '}':
				$this->data_pos--;
				$this->built[] = '))';
				break 2;

			// Maybe we're done with this?
			case ':':
				if ($key)
				{
					$this->built[] = '), array(';
				}
				else
				{
					$this->built[] = ',';
				}
				$key = false;
				$this->readVarPart($next);
				break;
			}
		}

		if ($brackets != 0)
			$this->toss('expression_brackets_unmatched');
	}