private function parseWithPreviousResult(InputStreamInterface $input, RepeaterExpressionResult $previous_result)
{
$part_results = $previous_result->getResults();
$length = count($part_results);
if ($length > 0) {
//we can backtrack the previous result
$index = $length - 1;
$position = $previous_result->getLength() - $part_results[$index]->getLength();
$input->move($position);
$last_part = $this->inner->parseInputStreamWithBacktracking($input, $part_results[$index]);
if ($last_part !== null) {
//succesfully backtracked, replace the entry
$part_results[$index] = $last_part;
return new RepeaterExpressionResult($part_results);
}
//failed to backtrack, fallthrough and find the next entry
$input->move($part_results[$index]->getLength());
}
if ($length >= $this->maximum) {
return null;
}
$next_result = $this->inner->parseInputStreamWithBacktracking($input);
if ($next_result === null) {
$input->move(-$previous_result->getLength());
return null;
}
$part_results[] = $next_result;
return new RepeaterExpressionResult($part_results);
}
private function parseWithPreviousResult(InputStreamInterface $input, RepeaterExpressionResult $previous_result)
{
$part_results = iterator_to_array($previous_result->getResults());
$length = count($part_results);
if ($length === 0) {
return null;
}
$index = $length - 1;
//we need to backtrack the last result.
//find the position where the last entry starts
$position = $previous_result->getLength() - $part_results[$index]->getLength();
$input->move($position);
//backtrack that entry
$last_part = $this->inner->parseInputStreamWithBacktracking($input, $part_results[$index]);
if ($last_part === null) {
//it failed, our new result excludes this item. Still atleast the minimum?
if ($index < $this->minimum) {
$input->move(-$position);
return null;
}
return new RepeaterExpressionResult(new \ArrayIterator(array_slice($part_results, 0, $index)));
}
//replace the entry
$part_results[$index] = $last_part;
return new RepeaterExpressionResult(new \ArrayIterator($part_results));
}
public function parseInputStreamWithBacktracking(InputStreamInterface $input, ExpressionResultInterface $previous_result = null)
{
if ($previous_result !== null) {
return null;
}
if ($input->isAtEnd() === false) {
return null;
}
return new ConstantExpressionResult("");
}
public function parseInputStreamWithBacktracking(InputStreamInterface $input, ExpressionResultInterface $previous_result = null)
{
if ($previous_result !== null) {
return null;
}
if ($input->matchesChar($this->string) === false) {
return null;
}
$input->move(1);
return $this->result;
}
public function parseInputStreamWithBacktracking(InputStreamInterface $input, ExpressionResultInterface $previous_result = null)
{
if ($previous_result !== null) {
return null;
}
$constant = $this->string;
if ($input->matchesString($constant) === false) {
return null;
}
$input->move(strlen($constant));
return $this->result;
}
public function parseInputStreamWithBacktracking(InputStreamInterface $input, ExpressionResultInterface $previous_result = null)
{
if ($previous_result !== null) {
return null;
}
$string = $input->getRemainingString();
$result = $this->string_parser->parse($string);
if ($result === null) {
$input->move(-strlen($string));
return null;
}
$input->move($result->getLength() - strlen($string));
return $result;
}
public function parseInputStreamWithBacktracking(InputStreamInterface $input, ExpressionResultInterface $previous_result = null)
{
if ($previous_result !== null && $previous_result instanceof ConcatenatedExpressionResult === false) {
throw new \Exception("Expected " . ConcatenatedExpressionResult::class);
}
/** @var ConcatenatedExpressionResult|null $previous_result */
$position = 0;
if ($previous_result !== null) {
$part_results = array_values($previous_result->getParts());
$index = count($this->parts) - 1;
for ($i = 0; $i < count($this->parts); $i += 1) {
$position += $part_results[$i]->getLength();
}
$input->move($position);
} else {
$part_results = array_fill(0, count($this->parts), null);
$index = 0;
}
for (; $index < count($this->parts);) {
$part = $this->parts[$index];
if ($part_results[$index] !== null) {
$input->move(-$part_results[$index]->getLength());
$position -= $part_results[$index]->getLength();
}
$part_result = $part->parseInputStreamWithBacktracking($input, $part_results[$index]);
if ($part_result === null) {
if ($index === 0) {
$input->move(-$position);
return null;
}
$part_results[$index] = $part_result;
$index -= 1;
} else {
$position += $part_result->getLength();
$part_results[$index] = $part_result;
$index += 1;
}
}
$corrected_part_results = array_combine($this->key_to_index, $part_results);
return new ConcatenatedExpressionResult($corrected_part_results);
}
