1: <?php
 2: 
 3: namespace BN\Compiler\Parser;
 4: 
 5: use BN\Compiler\Token\Token;
 6: use BN\Compiler\Token\TokenType;
 7: use BN\Compiler\Grammar\Operators;
 8: use BN\Compiler\Parser\Token\ParseValue;
 9: use BN\Compiler\Parser\Token\ParseOperator;
10: use BN\Compiler\Parser\Token\ParseOpeningBracket;
11: use BN\Compiler\Parser\Token\ParseClosingBracket;
12: use BN\Compiler\Parser\Token\ParseUnknownToken;
13: 
14: class ShuntingYardParser
15: {
16:     private $accumulator;
17:     private $parsers;
18:     private $postfix;
19:     private $tokensArray;
20: 
21:     public function __construct(ParserErrorHandler $errorHandler, Operators $operators)
22:     {
23:         $this->accumulator = new QueueAccumulator($errorHandler);
24:         $this->postfix = new StackCleaning($this->accumulator);
25:         $parseValue = new ParseValue($this->accumulator);
26:         $parseOperator = new ParseOperator($this->accumulator, $operators);
27:         $this->parsers = array(
28:             TokenType::NUMBER => $parseValue,
29:             TokenType::VARIABLE => $parseValue,
30:             TokenType::CONSTANT => $parseValue,
31:             TokenType::ASSIGN => $parseOperator,
32:             TokenType::OPERATOR => $parseOperator,
33:             TokenType::BRACKET_OPENING => new ParseOpeningBracket($this->accumulator),
34:             TokenType::BRACKET_CLOSING => new ParseClosingBracket($this->accumulator),
35:             TokenType::UNKNOWN => new ParseUnknownToken($this->accumulator)
36:         );
37:     }
38: 
39:     public function parse(array $tokensInInfixNotation)
40:     {
41:         $this->prepareParser($tokensInInfixNotation);
42:         while ($this->existsUnreadToken()) {
43:             $this->readNextToken();
44:         }
45:         $this->pushOperatorsFromStack();
46:         return $this->getTokensInPostfixNotation();
47:     }
48: 
49:     private function prepareParser($tokens)
50:     {
51:         $this->tokensArray = $tokens;
52:         $this->accumulator->init();
53:     }
54: 
55:     private function existsUnreadToken()
56:     {
57:         return !empty($this->tokensArray);
58:     }
59: 
60:     private function readNextToken()
61:     {
62:         $token = array_shift($this->tokensArray);
63:         $parser = $this->getParser($token);
64:         $parser->parse($token);
65:     }
66: 
67:     private function getParser(Token $token)
68:     {
69:         if (array_key_exists($token->type, $this->parsers)) {
70:             return $this->parsers[$token->type];
71:         } else {
72:             return $this->parsers[TokenType::UNKNOWN];
73:         }
74:     }
75: 
76:     private function pushOperatorsFromStack()
77:     {
78:         $this->postfix->pushOperatorsFromStack();
79:     }
80: 
81:     private function getTokensInPostfixNotation()
82:     {
83:         return $this->accumulator->getResult();
84:     }
85: }
86: