1: <?php
 2: 
 3: namespace BN\Compiler\Scanner\Converter;
 4: 
 5: use BN\Compiler\Token\Token;
 6: use BN\Compiler\Token\TokenType;
 7: use BN\Compiler\Scanner\LexemeConverter;
 8: 
 9: class LexemeToSignedNumber implements LexemeConverter
10: {
11:     public function canConvertLexeme($lexeme)
12:     {
13:         return $this->isStringNumeric($lexeme)
14:             || $this->numberWithUnarySign($lexeme);
15:     }
16: 
17:     private function isStringNumeric($lexeme)
18:     {
19:         return is_string($lexeme) && is_numeric($lexeme);
20:     }
21: 
22:     private function numberWithUnarySign($lexeme)
23:     {
24:         $afterSign = substr($lexeme, 1);
25:         return $this->startWithUnarySign($lexeme)
26:             && $this->isStringNumeric($afterSign)
27:             && $this->noUnarySign($afterSign);
28:     }
29: 
30:     private function noUnarySign($lexeme)
31:     {
32:         return !$this->startWithUnarySign($lexeme);
33:     }
34: 
35:     private function startWithUnarySign($lexeme)
36:     {
37:         return in_array($lexeme[0], array('+', '-'), true);
38:     }
39: 
40:     public function convertLexeme($lexeme)
41:     {
42:         return new Token(TokenType::NUMBER, $lexeme);
43:     }
44: }
45: