public function parseInputStreamWithBacktracking(InputStreamInterface $input, ExpressionResultInterface $previous_result = null)
{
/** @var AlternativeExpressionResult $previous_result */
if ($previous_result !== null && $previous_result instanceof AlternativeExpressionResult === false) {
throw new \Exception("Expected " . AlternativeExpressionResult::class);
}
$alternatives = $this->alternatives;
/** @var BacktrackingStreamingParserInterface|false $current_alternative */
$current_alternative = reset($alternatives);
$active = $previous_result === null;
while ($active === false) {
$active = key($alternatives) === $previous_result->getKey();
if ($active === true) {
$alternative_result = $current_alternative->parseInputStreamWithBacktracking($input, $previous_result->getResult());
if ($alternative_result !== null) {
return new AlternativeExpressionResult($alternative_result, key($alternatives));
}
}
$current_alternative = next($alternatives);
}
while ($current_alternative !== false) {
$current_alternative = current($alternatives);
$alternative_result = $current_alternative->parseInputStreamWithBacktracking($input);
if ($alternative_result !== null) {
if ($previous_result !== null && $previous_result->getLength() === $alternative_result->getLength()) {
return null;
}
return new AlternativeExpressionResult($alternative_result, key($alternatives));
}
$current_alternative = next($alternatives);
}
return null;
}
public function reverseRewriteExpressionResult(ExpressionResultInterface $result)
{
/** @var \PeterVanDommelen\Parser\Expression\Alternative\AlternativeExpressionResult $result */
$key = $result->getKey();
$original_result = $this->alternative_rewriters[$key]->reverseRewriteExpressionResult($result->getResult());
return new AlternativeExpressionResult($original_result, $key);
}
public function reverseRewriteExpressionResult(ExpressionResultInterface $result)
{
/** @var AlternativeExpressionResult $result */
if ($result->getKey() === 1) {
//empty
return new JoinedExpressionResult(array(), array());
}
/** @var \PeterVanDommelen\Parser\Expression\Concatenated\ConcatenatedExpressionResult $maybe_part */
$maybe_part = $result->getResult();
/** @var \PeterVanDommelen\Parser\Expression\Repeater\RepeaterExpressionResult $repeater_part */
$repeater_part = $maybe_part->getPart(1);
$results = array($this->inner_result_rewriter->reverseRewriteExpressionResult($maybe_part->getPart(0)));
$seperators = array();
foreach ($repeater_part->getResults() as $repeater_part_part) {
/** @var \PeterVanDommelen\Parser\Expression\Concatenated\ConcatenatedExpressionResult $repeater_part_part */
$seperators[] = $this->seperator_result_rewriter->reverseRewriteExpressionResult($repeater_part_part->getPart(0));
$results[] = $this->inner_result_rewriter->reverseRewriteExpressionResult($repeater_part_part->getPart(1));
}
return new JoinedExpressionResult($results, $seperators);
}
