aboutsummaryrefslogtreecommitdiff
path: root/src/NXP/Classes/Lexer.php
diff options
context:
space:
mode:
Diffstat (limited to 'src/NXP/Classes/Lexer.php')
-rw-r--r--src/NXP/Classes/Lexer.php161
1 files changed, 0 insertions, 161 deletions
diff --git a/src/NXP/Classes/Lexer.php b/src/NXP/Classes/Lexer.php
deleted file mode 100644
index 9964de9..0000000
--- a/src/NXP/Classes/Lexer.php
+++ /dev/null
@@ -1,161 +0,0 @@
-<?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\TokenMinus;
-use NXP\Classes\Token\TokenNumber;
-use NXP\Classes\Token\TokenRightBracket;
-use NXP\Classes\Token\TokenStringDoubleQuoted;
-use NXP\Classes\Token\TokenStringSingleQuoted;
-use NXP\Classes\Token\TokenVariable;
-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 = [];
- $lastToken = null;
-
- foreach ($tokensStream as $token) {
- if ($token instanceof TokenStringDoubleQuoted) {
- $output[] = $token;
- } elseif ($token instanceof TokenStringSingleQuoted) {
- $output[] = $token;
- } elseif ($token instanceof TokenNumber) {
- // if the number starts with a minus sign, it could be a negative number, or it could be an operator grabbed by the greedy regex
- // if previous token is an operator or open bracket, then it negative, otherwise remove the minus sign and put a negative operator on the stack
- if ($lastToken !== null) {
- $value = $token->getValue();
- if (($value < 0 || $this->isNegativeZero($value)) && ! ($lastToken instanceof AbstractOperator || $lastToken instanceof TokenLeftBracket)) {
- $token = new TokenNumber(abs($value));
- $output[] = $token;
- $output[] = new TokenMinus('-');
- } else {
- $output[] = $token;
- }
- } else {
- $output[] = $token;
- }
- } elseif ($token instanceof TokenVariable) {
- $output[] = $token;
- } elseif ($token instanceof TokenFunction) {
- $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);
- }
-
- // Comma operators do nothing really, don't put them on the stack
- if (! ($token instanceof TokenComma)) {
- $stack[] = $token;
- }
- } elseif ($token instanceof TokenLeftBracket) {
- $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);
- }
- }
- $lastToken = $token;
- }
- while (!empty($stack)) {
- $token = array_pop($stack);
- if ($token instanceof TokenLeftBracket || $token instanceof TokenRightBracket) {
- throw new IncorrectBracketsException();
- }
- $output[] = $token;
- }
-
- return $output;
- }
-
- /**
- * Check if the value is a negative zero
- *
- * @param int|float $x The value to check
- * @return boolean True if negative zero, false otherwise
- */
- private function isNegativeZero($x)
- {
- $floatVal = floatval($x);
-
- return $floatVal === 0.0 && $floatVal ** -1 === -INF;
- }
-}