blob: a511c9b9e25d98dfc174bb4b6b5339f51fd68119 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
|
<?php
/**
* This file is part of the MathExecutor package
*
* (c) Alexander Kiryukhin
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code
*/
namespace NXP\Classes;
use NXP\Classes\Token\AbstractOperator;
use NXP\Classes\Token\InterfaceOperator;
use NXP\Classes\Token\TokenComma;
use NXP\Classes\Token\TokenFunction;
use NXP\Classes\Token\TokenLeftBracket;
use NXP\Classes\Token\TokenNumber;
use NXP\Classes\Token\TokenRightBracket;
use NXP\Classes\Token\TokenStringSingleQuoted;
use NXP\Classes\Token\TokenVariable;
use NXP\Classes\Token\TokenStringDoubleQuoted;
use NXP\Exception\IncorrectBracketsException;
use NXP\Exception\IncorrectExpressionException;
/**
* @author Alexander Kiryukhin <a.kiryukhin@mail.ru>
*/
class Lexer
{
/**
* @var TokenFactory
*/
private $tokenFactory;
public function __construct($tokenFactory)
{
$this->tokenFactory = $tokenFactory;
}
/**
* @param string $input Source string of equation
* @return array Tokens stream
*/
public function stringToTokensStream($input)
{
$matches = [];
preg_match_all($this->tokenFactory->getTokenParserRegex(), $input, $matches);
$tokenFactory = $this->tokenFactory;
$tokensStream = array_map(
function ($token) use ($tokenFactory) {
return $tokenFactory->createToken($token);
},
$matches[0]
);
return $tokensStream;
}
/**
* @param array $tokensStream Tokens stream
* @return array Array of tokens in revers polish notation
* @throws IncorrectBracketsException
*/
public function buildReversePolishNotation($tokensStream)
{
$output = [];
$stack = [];
foreach ($tokensStream as $token) {
if ($token instanceof TokenStringDoubleQuoted) {
$output[] = $token;
} elseif ($token instanceof TokenStringSingleQuoted) {
$output[] = $token;
} elseif ($token instanceof TokenNumber) {
$output[] = $token;
} elseif ($token instanceof TokenVariable) {
$output[] = $token;
} elseif ($token instanceof TokenFunction) {
array_push($stack, $token);
} elseif ($token instanceof AbstractOperator) {
// While we have something on the stack
while (($count = count($stack)) > 0
&& (
// If it is a function
($stack[$count - 1] instanceof TokenFunction)
||
// Or the operator at the top of the operator stack
// has (left associative and equal precedence)
// or has greater precedence
(($stack[$count - 1] instanceof InterfaceOperator) &&
(
($stack[$count - 1]->getAssociation() == AbstractOperator::LEFT_ASSOC &&
$token->getPriority() == $stack[$count - 1]->getPriority())
||
($stack[$count - 1]->getPriority() > $token->getPriority())
)
)
)
// And not a left bracket
&& (!($stack[$count - 1] instanceof TokenLeftBracket))) {
$output[] = array_pop($stack);
}
array_push($stack, $token);
} elseif ($token instanceof TokenLeftBracket) {
array_push($stack, $token);
} elseif ($token instanceof TokenRightBracket) {
while (($current = array_pop($stack)) && (!($current instanceof TokenLeftBracket))) {
$output[] = $current;
}
if (!empty($stack) && ($stack[count($stack) - 1] instanceof TokenFunction)) {
$output[] = array_pop($stack);
}
}
}
while (!empty($stack)) {
$token = array_pop($stack);
if ($token instanceof TokenLeftBracket || $token instanceof TokenRightBracket) {
throw new IncorrectBracketsException();
}
$output[] = $token;
}
return $output;
}
}
|
