diff options
Diffstat (limited to 'src/NXP/Classes')
| -rw-r--r-- | src/NXP/Classes/Lexer.php | 16 | ||||
| -rw-r--r-- | src/NXP/Classes/Token/TokenMinus.php | 8 |
2 files changed, 20 insertions, 4 deletions
diff --git a/src/NXP/Classes/Lexer.php b/src/NXP/Classes/Lexer.php index 73c25ac..cd12d21 100644 --- a/src/NXP/Classes/Lexer.php +++ b/src/NXP/Classes/Lexer.php @@ -78,8 +78,8 @@ class Lexer // 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, then it negative, otherwise remove the minus sign and put a negative operator on the stack if ($lastToken !== null) { - $value = (int)$token->getValue(); - if ($value < 0 && ! ($lastToken instanceof AbstractOperator)) { + $value = $token->getValue(); + if (($value < 0 || $this->isNegativeZero($value)) && ! ($lastToken instanceof AbstractOperator)) { $token = new TokenNumber(abs($value)); $output[] = $token; $output[] = new TokenMinus('-'); @@ -145,4 +145,16 @@ class Lexer 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; + } } diff --git a/src/NXP/Classes/Token/TokenMinus.php b/src/NXP/Classes/Token/TokenMinus.php index d8ac079..b4b04e3 100644 --- a/src/NXP/Classes/Token/TokenMinus.php +++ b/src/NXP/Classes/Token/TokenMinus.php @@ -53,8 +53,12 @@ class TokenMinus extends AbstractOperator $op2 = array_pop($stack); $op1 = array_pop($stack); - if ($op1 === null || $op2 === null) { - throw new IncorrectExpressionException("Subtraction requires two operators"); + if ($op2 === null) { + throw new IncorrectExpressionException("Subtraction requires right operator"); + } + + if (!$op1) { + $op1 = new TokenNumber(0); } $result = $op1->getValue() - $op2->getValue(); |