diff options
Diffstat (limited to 'Calc.php')
| -rw-r--r-- | Calc.php | 138 |
1 files changed, 0 insertions, 138 deletions
diff --git a/Calc.php b/Calc.php deleted file mode 100644 index e8dba8d..0000000 --- a/Calc.php +++ /dev/null @@ -1,138 +0,0 @@ -<?php - -namespace kch42\ste; - -/* Class Calc contains static methods needed by <ste:calc /> */ -class Calc { - private function __construct() {} - - /* We could also just eval() the $infix_math code, but this is much cooler :-D (Parser inception) */ - public static function shunting_yard($infix_math) { - $operators = array( - "+" => array("l", 2), - "-" => array("l", 2), - "*" => array("l", 3), - "/" => array("l", 3), - "^" => array("r", 4), - "_" => array("r", 5), - "(" => array("", 0), - ")" => array("", 0) - ); - - preg_match_all("/\s*(?:(?:[+\\-\\*\\/\\^\\(\\)])|(\\d*[\\.]?\\d*))\\s*/s", $infix_math, $tokens, PREG_PATTERN_ORDER); - $tokens_raw = array_filter(array_map('trim', $tokens[0]), function($x) { return ($x === "0") || (!empty($x)); }); - $output_queue = array(); - $op_stack = array(); - - $lastpriority = NULL; - /* Make - unary, if neccessary */ - $tokens = array(); - foreach($tokens_raw as $token) { - $priority = isset($operators[$token]) ? $operators[$token][1] : -1; - if(($token == "-") && (($lastpriority === NULL) || ($lastpriority >= 0))) { - $priority = $operators["_"][1]; - $tokens[] = "_"; - } else { - $tokens[] = $token; - } - $lastpriority = $priority; - } - - while(!empty($tokens)) { - $token = array_shift($tokens); - if(is_numeric($token)) { - $output_queue[] = $token; - } else if($token == "(") { - $op_stack[] = $token; - } else if($token == ")") { - $lbr_found = false; - while(!empty($op_stack)) { - $op = array_pop($op_stack); - if($op == "(") { - $lbr_found = true; - break; - } - $output_queue[] = $op; - } - if(!$lbr_found) { - throw new RuntimeError("Bracket mismatch."); - } - } else if(!isset($operators[$token])) { - throw new RuntimeError("Invalid token ($token): Not a number, bracket or operator. Stop."); - } else { - $priority = $operators[$token][1]; - if($operators[$token][0] == "l") { - while((!empty($op_stack)) and ($priority <= $operators[$op_stack[count($op_stack)-1]][1])) { - $output_queue[] = array_pop($op_stack); - } - } else { - while((!empty($op_stack)) and ($priority < $operators[$op_stack[count($op_stack)-1]][1])) { - $output_queue[] = array_pop($op_stack); - } - } - $op_stack[] = $token; - } - } - - while(!empty($op_stack)) { - $op = array_pop($op_stack); - if($op == "(") { - throw new RuntimeError("Bracket mismatch..."); - } - $output_queue[] = $op; - } - - return $output_queue; - } - - public static function pop2(&$array) { - $rv = array(array_pop($array), array_pop($array)); - if(array_search(NULL, $rv, true) !== false) { - throw new RuntimeError("Not enough numbers on stack. Invalid formula."); - } - return $rv; - } - - public static function calc_rpn($rpn) { - $stack = array(); - foreach($rpn as $token) { - switch($token) { - case "+": - list($b, $a) = self::pop2($stack); - $stack[] = $a + $b; - break; - case "-": - list($b, $a) = self::pop2($stack); - $stack[] = $a - $b; - break; - case "*": - list($b, $a) = self::pop2($stack); - $stack[] = $a * $b; - break; - case "/": - list($b, $a) = self::pop2($stack); - $stack[] = $a / $b; - break; - case "^": - list($b, $a) = self::pop2($stack); - $stack[] = pow($a, $b); - break; - case "_": - $a = array_pop($stack); - if($a === NULL) { - throw new RuntimeError("Not enough numbers on stack. Invalid formula."); - } - $stack[] = -$a; - break; - default: - $stack[] = $token; - break; - } - } - return array_pop($stack); - } - - public static function calc($expr) { - return self::calc_rpn(self::shunting_yard($expr)); - } -}
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