Make changes in functionality, originally implemented by Petr to make

maths class suitable for use in grade book, dependent on boolean
switches in constructor which default to having the changes 'on'.

lib/evalmath/evalmath.class.php

@@ -111,7 +111,14 @@ class EvalMath {
         'mod'=>array(2),      'pi'=>array(0),    'power'=>array(2),
         'round'=>array(1, 2), 'sum'=>array(-1));
 
-    function EvalMath() {
+    var $allowimplicitmultiplication;
+
+    function EvalMath($allowconstants = false, $allowimplicitmultiplication = false) {
+        if ($allowconstants){
+            $this->v['pi'] = pi();
+            $this->v['e'] = exp(1);
+        }
+        $this->allowimplicitmultiplication = $allowimplicitmultiplication;
     }
 
     function e($expr) {
@@ -203,8 +210,12 @@ class EvalMath {
             //===============
             } elseif ((in_array($op, $ops) or $ex) and $expecting_op) { // are we putting an operator on the stack?
                 if ($ex) { // are we expecting an operator but have a number/variable/function/opening parethesis?
-                    return $this->trigger("expecting operand");
-                    //$op = '*'; $index--; // it's an implicit multiplication
+                    if (!$this->allowimplicitmultiplication){
+                        return $this->trigger("expecting operator, implicit multiplication not allowed.");
+                    } else {// it's an implicit multiplication
+                        $op = '*';
+                        $index--;
+                    }
                 }
                 // heart of the algorithm:
                 while($stack->count > 0 and ($o2 = $stack->last()) and in_array($o2, $ops) and ($ops_r[$op] ? $ops_p[$op] < $ops_p[$o2] : $ops_p[$op] <= $ops_p[$o2])) {