lib/Boris/ShallowParser.php
<?php
namespace Boris;
/**
* The ShallowParser takes whatever is currently buffered and chunks it into individual statements.
*/
class ShallowParser
{
private $_pairs = array('(' => ')', '{' => '}', '[' => ']', '"' => '"', "'" => "'", '//' => "\n", '#' => "\n", '/*' => '*/', '<<<' => '_heredoc_special_case_');
private $_initials;
public function __construct()
{
$this->_initials = '/^(' . implode('|', array_map(array(
$this,
'quote'
), array_keys($this->_pairs))) . ')/';
}
/**
* Break the $buffer into chunks, with one for each highest-level construct possible.
*
* If the buffer is incomplete, returns an empty array.
*
* @param string $buffer
*
* @return array
*/
public function statements($buffer)
{
$result = $this->_createResult($buffer);
while (strlen($result->buffer) > 0) {
$this->_resetResult($result);
if ($result->state == '<<<') {
if (!$this->_initializeHeredoc($result)) {
continue;
}
}
$rules = array(
'_scanUse',
'_scanEscapedChar',
'_scanRegion',
'_scanStateEntrant',
'_scanWsp',
'_scanChar'
);
foreach ($rules as $method) {
if ($this->$method($result)) {
break;
}
}
if ($result->stop) {
break;
}
}
if (!empty($result->statements) && trim($result->stmt) === '' && strlen($result->buffer) == 0) {
$this->_combineStatements($result);
$this->_prepareForDebug($result);
return $result->statements;
}
}
public function quote($token)
{
return preg_quote($token, '/');
}
// -- Private Methods
private function _createResult($buffer)
{
$result = new \stdClass();
$result->buffer = $buffer;
$result->stmt = '';
$result->state = null;
$result->states = array();
$result->statements = array();
$result->stop = false;
return $result;
}
private function _resetResult($result)
{
$result->stop = false;
$result->state = end($result->states);
$result->terminator = $result->state ? '/^(.*?' . preg_quote($this->_pairs[$result->state], '/') . ')/s' : null;
}
private function _combineStatements($result)
{
$combined = array();
foreach ($result->statements as $scope) {
if (trim($scope) == ';' || substr(trim($scope), -1) != ';') {
$combined[] = ((string) array_pop($combined)) . $scope;
} else {
$combined[] = $scope;
}
}
$result->statements = $combined;
}
private function _prepareForDebug($result)
{
$result->statements[] = $this->_prepareDebugStmt(array_pop($result->statements));
}
private function _initializeHeredoc($result)
{
if (preg_match('/^([\'"]?)([a-z_][a-z0-9_]*)\\1/i', $result->buffer, $match)) {
$docId = $match[2];
$result->stmt .= $match[0];
$result->buffer = substr($result->buffer, strlen($match[0]));
$result->terminator = '/^(.*?\n' . $docId . ');?\n/s';
return true;
} else {
return false;
}
}
private function _scanWsp($result)
{
if (preg_match('/^\s+/', $result->buffer, $match)) {
if (!empty($result->statements) && $result->stmt === '') {
$result->statements[] = array_pop($result->statements) . $match[0];
} else {
$result->stmt .= $match[0];
}
$result->buffer = substr($result->buffer, strlen($match[0]));
return true;
} else {
return false;
}
}
private function _scanEscapedChar($result)
{
if (($result->state == '"' || $result->state == "'") && preg_match('/^[^' . $result->state . ']*?\\\\./s', $result->buffer, $match)) {
$result->stmt .= $match[0];
$result->buffer = substr($result->buffer, strlen($match[0]));
return true;
} else {
return false;
}
}
private function _scanRegion($result)
{
if (in_array($result->state, array(
'"',
"'",
'<<<',
'//',
'#',
'/*'
))) {
if (preg_match($result->terminator, $result->buffer, $match)) {
$result->stmt .= $match[1];
$result->buffer = substr($result->buffer, strlen($match[1]));
array_pop($result->states);
} else {
$result->stop = true;
}
return true;
} else {
return false;
}
}
private function _scanStateEntrant($result)
{
if (preg_match($this->_initials, $result->buffer, $match)) {
$result->stmt .= $match[0];
$result->buffer = substr($result->buffer, strlen($match[0]));
$result->states[] = $match[0];
return true;
} else {
return false;
}
}
private function _scanChar($result)
{
$chr = substr($result->buffer, 0, 1);
$result->stmt .= $chr;
$result->buffer = substr($result->buffer, 1);
if ($result->state && $chr == $this->_pairs[$result->state]) {
array_pop($result->states);
}
if (empty($result->states) && ($chr == ';' || $chr == '}')) {
if (!$this->_isLambda($result->stmt) || $chr == ';') {
$result->statements[] = $result->stmt;
$result->stmt = '';
}
}
return true;
}
private function _scanUse($result)
{
if (preg_match("/^use (.+?);/", $result->buffer, $use)) {
$result->buffer = substr($result->buffer, strlen($use[0]));
if (strpos($use[0], ' as ') !== false) {
list($class, $alias) = explode(' as ', $use[1]);
} else {
$class = $use[1];
$alias = substr($use[1], strrpos($use[1], '\\') + 1);
}
$result->statements[] = sprintf("class_alias('%s', '%s');", $class, $alias);
return true;
} else {
return false;
}
}
private function _isLambda($input)
{
return preg_match('/^([^=]*?=\s*)?function\s*\([^\)]*\)\s*(use\s*\([^\)]*\)\s*)?\s*\{.*\}\s*;?$/is', trim($input));
}
private function _isReturnable($input)
{
$input = trim($input);
if (substr($input, -1) == ';' && substr($input, 0, 1) != '{') {
return $this->_isLambda($input) || !preg_match('/^(' . 'echo|print|exit|die|goto|global|include|include_once|require|require_once|list|' . 'return|do|for|foreach|while|if|function|namespace|class|interface|abstract|switch|' . 'declare|throw|try|unset' . ')\b/i', $input);
} else {
return false;
}
}
private function _prepareDebugStmt($input)
{
if ($this->_isReturnable($input) && !preg_match('/^\s*return/i', $input)) {
$input = sprintf('return %s', $input);
}
return $input;
}
}