protected function doScan(Scanner $scanner)
{
$quotechar = $scanner->tokenType();
$ret = false;
$string = "";
while ($token = $scanner->nextToken()) {
if ($token == $quotechar) {
$ret = true;
break;
}
$string .= $scanner->token();
}
if ($string && !$this->discard) {
$scanner->getContext()->pushResult($string);
}
return $ret;
}
final function scan(Scanner $scanner)
{
if ($scanner->tokenType() == Scanner::SOF) {
$scanner->nextToken();
}
$ret = $this->doScan($scanner);
if ($ret && !$this->discard && $this->term()) {
$this->push($scanner);
}
if ($ret) {
$this->invokeHandler($scanner);
}
if ($this->term() && $ret) {
$this->next($scanner);
}
$this->report("::scan returning {$ret}");
return $ret;
}
/**
* sign: '!' sign | '+' sign | '-' sign | index
*/
private static function parseSign(Scanner $scanner)
{
switch ($scanner->tokenType()) {
case '!':
$scanner->nextToken();
$result = new NotExpression(self::parseSign($scanner));
break;
case '+':
$scanner->nextToken();
$result = self::parseSign($scanner);
break;
case '-':
$scanner->nextToken();
$result = new MinusExpression(self::parseSign($scanner));
break;
default:
$result = self::parseIndex($scanner);
}
return $result;
}
}
$char = substr($this->in, $this->pos, 1);
$this->pos++;
return $char;
}
public function getPos()
{
return $this->pos;
}
public function pushBackChar()
{
$this->pos--;
}
public function string()
{
return $this->in;
}
}
/**
* Demo
*/
$context = new Context();
$user_in = "\$input equals '4' or \$input equals 'four'";
$reader = new StringReader($user_in);
$scanner = new Scanner($reader, $context);
while ($scanner->nextToken() != Scanner::EOF) {
// var_dump($scanner->token(), $scanner->char_no(), $scanner->getTypeString());
print $scanner->token();
print "\t{$scanner->char_no()}";
print "\t{$scanner->getTypeString()}\n";
}
public function testPeekToken()
{
$grammar = "comment :== literal .";
$scanner = new Scanner(trim($grammar));
$scanner->nextToken();
$t = $scanner->currentToken();
$this->assertEquals("comment", $t->getValue());
$this->assertEquals(":==", $scanner->peekToken()->getValue());
$scanner->nextToken();
$t = $scanner->currentToken();
$this->assertEquals(":==", $t->getValue());
$this->assertEquals("literal", $scanner->peekToken()->getValue());
$scanner->nextToken();
$t = $scanner->currentToken();
$this->assertEquals("literal", $t->getValue());
$scanner->nextToken();
$t = $scanner->currentToken();
$this->assertEquals(".", $t->getValue());
$scanner->nextToken();
$t = $scanner->currentToken();
$this->assertEquals(Token::EOF, $t->getType());
}
