플러그인 31: 표현식 값 구하기

<?php // Plug-in 31: Evaluate Expression

// This is an executable example with additional code supplied
// To obtain just the plug-ins please click on the Download link

echo "<font face='Courier New'><pre>";
$s = "TAN(64)";
echo "$s\t\t\t= " . PIPHP_EvaluateExpression($s) . "
";
$s = "sqrt(77.3) / 99";
echo "$s\t\t= "   . PIPHP_EvaluateExpression($s) . "
";
$s = "1 + 2 / 3 * 4 - 5";
echo "$s\t= "     . PIPHP_EvaluateExpression($s) . "
";
$s = "log(100)";
echo "$s\t\t= "   . PIPHP_EvaluateExpression($s) . "
";
$s = "pi()";
echo "$s\t\t\t= " . PIPHP_EvaluateExpression($s) . "
";

function PIPHP_EvaluateExpression($expr)
{
   // Plug-in 31: Evaluate Expression
   //
   // This plug-in accepts a string containing an arithmetic
   // expression and returns the result of evaluating it.
   // Over 20 functions are also supported. The argument
   // required is:
   //
   //    $expr: The arithmetic expression
   
   $f1 = array ('abs',   'acos',  'acosh', 'asin',  'asinh',
                'atan',  'atan2', 'atanh', 'cos',   'cosh',
                'exp',   'expm1', 'log',   'log10', 'log1p',
                'pi',    'pow',   'sin',   'sinh',  'sqrt',
                'tan',   'tanh');

   $f2 = array ('!01!',  '!02!',  '!03!',  '!04!',  '!05!',
                '!06!',  '!07!',  '!08!',  '!09!',  '!10!',
                '!11!',  '!12!',  '!13!',  '!14!',  '!15!',
                '!16!',  '!17!',  '!18!',  '!19!',  '!20!',
                '!21!',  '!22!');

   $expr = strtolower($expr);
   $expr = str_replace($f1, $f2, $expr);
   $expr = preg_replace("/[^\d\+\*\/\-\.(),! ]/", '', $expr);
   $expr = str_replace($f2, $f1, $expr);

   // Uncomment the line below to see the sanitized expression
   // echo "$expr<br />
";

   return eval("return $expr;");
}

?>