MDL-27418 add validation to stop students intering a thosands sep.

If it might be confused by a decimal point from another locale.

question/type/numerical/lang/en/qtype_numerical.php

@@ -64,6 +64,7 @@
 $string['onlynumerical'] = 'Units are not used at all. Only the numerical value is graded.';
 $string['oneunitshown'] = 'Unit 1 is automatically displayed beside the answer box.';
 $string['pleaseenterananswer'] = 'Please enter an answer.';
+$string['pleaseenteranswerwithoutthousandssep'] = 'Please enter your answer without using the thousand separator ({$a}).';
 $string['relative'] = 'Relative';
 $string['rightexample'] = 'on the right, for example 1.00cm or 1.00km';
 $string['selectunits'] = 'Select units';

question/type/numerical/question.php

@@ -109,6 +109,10 @@ public function is_complete_response(array $response) {
             return false;
         }
 
+        if ($this->ap->contains_thousands_seaparator($response['answer'])) {
+            return false;
+        }
+
         return true;
     }
 
@@ -130,6 +134,11 @@ public function get_validation_error(array $response) {
             return get_string('unitnotselected', 'qtype_numerical');
         }
 
+        if ($this->ap->contains_thousands_seaparator($response['answer'])) {
+            return get_string('pleaseenteranswerwithoutthousandssep', 'qtype_numerical',
+                    $this->ap->get_separator());
+        }
+
         return '';
     }
 

question/type/numerical/questiontype.php

@@ -524,6 +524,19 @@ public function get_separator() {
         return $this->thousandssep;
     }
 
+    /**
+     * @return book If the student's response contains a '.' or a ',' that
+     * matches the thousands separator in the current locale. In this case, the
+     * parsing in apply_unit can give a result that the student did not expect.
+     */
+    public function contains_thousands_seaparator($value) {
+        if (!in_array($this->thousandssep, array('.', ','))) {
+            return false;
+        }
+
+        return strpos($value, $this->thousandssep) !== false;
+    }
+
     /**
      * Create the regular expression that {@link parse_response()} requires.
      * @return string