MDL-27418 qtype numeric go back to the very permissive number parsing…

… from Moodle 2.0.

I hope my unit tests are good enough to make this change safe.

question/type/numerical/questiontype.php

@@ -550,6 +550,11 @@ protected function build_regex() {
     }
 
     /**
+     * This method can be used for more locale-strict parsing of repsonses. At the
+     * moment we don't use it, and instead use the more lax parsing in apply_units.
+     * This is just a note that this funciton was used in the past, so if you are
+     * intersted, look through version control history.
+     *
      * Take a string which is a number with or without a decimal point and exponent,
      * and possibly followed by one of the units, and split it into bits.
      * @param string $response a value, optionally with a unit.
@@ -585,25 +590,44 @@ protected function parse_response($response) {
     }
 
     /**
-     * Takes a number in localised form, that is, using the decsep and thousandssep
-     * defined in the lanuage pack, and possibly with a unit after it. It separates
-     * off the unit, if present, and converts to the default unit, by using the
-     * given unit multiplier.
+     * Takes a number in almost any localised form, and possibly with a unit
+     * after it. It separates off the unit, if present, and converts to the
+     * default unit, by using the given unit multiplier.
      *
      * @param string $response a value, optionally with a unit.
      * @return array(numeric, sting) the value with the unit stripped, and normalised
      *      by the unit multiplier, if any, and the unit string, for reference.
      */
     public function apply_units($response, $separateunit = null) {
-        list($beforepoint, $decimals, $exponent, $unit) = $this->parse_response($response);
+        // Strip spaces (which may be thousands separators) and change other forms
+        // of writing e to e.
+        $response = str_replace(' ', '', $response);
+        $response = preg_replace('~(?:e|E|(?:x|\*|×)10(?:\^|\*\*))([+-]?\d+)~', 'e$1', $response);
+
+        // If a . is present or there are multiple , (i.e. 2,456,789 ) assume ,
+        // is a thouseands separator, and strip it, else assume it is a decimal
+        // separator, and change it to ..
+        if (strpos($response, '.') !== false || substr_count($response, ',') > 1) {
+            $response = str_replace(',', '', $response);
+        } else {
+            $response = str_replace(',', '.', $response);
+        }
 
-        if (is_null($beforepoint)) {
+        $regex = '[+-]?(?:\d+(?:\\.\d*)?|\\.\d+)(?:e[-+]?\d+)?';
+        if ($this->unitsbefore) {
+            $regex = "/$regex$/";
+        } else {
+            $regex = "/^$regex/";
+        }
+        if (!preg_match($regex, $response, $matches)) {
             return array(null, null);
         }
 
-        $numberstring = $beforepoint . '.' . $decimals;
-        if ($exponent) {
-            $numberstring .= 'e' . $exponent;
+        $numberstring = $matches[0];
+        if ($this->unitsbefore) {
+            $unit = substr($response, 0, -strlen($numberstring));
+        } else {
+            $unit = substr($response, strlen($numberstring));
         }
 
         if (!is_null($separateunit)) {

question/type/numerical/simpletest/testform.php

@@ -71,10 +71,10 @@ public function tearDown() {
 
     public function test_is_valid_number() {
         $this->assertTrue($this->form->is_valid_number('1,001'));
-        $this->assertFalse($this->form->is_valid_number('1.001'));
+        $this->assertTrue($this->form->is_valid_number('1.001'));
         $this->assertTrue($this->form->is_valid_number('1'));
         $this->assertTrue($this->form->is_valid_number('1,e8'));
         $this->assertFalse($this->form->is_valid_number('1001 xxx'));
-        $this->assertFalse($this->form->is_valid_number('1.e8'));
+        $this->assertTrue($this->form->is_valid_number('1.e8'));
     }
 }

question/type/numerical/simpletest/testquestion.php

@@ -110,17 +110,17 @@ public function test_grading_currency() {
         $this->assertEqual(array(1, question_state::$gradedright),
                 $question->grade_response(array('answer' => '$1332')));
         $this->assertEqual(array(1, question_state::$gradedright),
-                $question->grade_response(array('answer' => '$ 1,332')));
+                $question->grade_response(array('answer' => '$ 1332')));
         $this->assertEqual(array(0.8, question_state::$gradedpartial),
                 $question->grade_response(array('answer' => 'frog 1332')));
         $this->assertEqual(array(0.8, question_state::$gradedpartial),
                 $question->grade_response(array('answer' => '1332')));
         $this->assertEqual(array(0.8, question_state::$gradedpartial),
-                $question->grade_response(array('answer' => ' 1,332')));
+                $question->grade_response(array('answer' => ' 1332')));
         $this->assertEqual(array(0, question_state::$gradedwrong),
                 $question->grade_response(array('answer' => '1332 $')));
         $this->assertEqual(array(0, question_state::$gradedwrong),
-                $question->grade_response(array('answer' => '1,332 frogs')));
+                $question->grade_response(array('answer' => '1332 frogs')));
         $this->assertEqual(array(0, question_state::$gradedwrong),
                 $question->grade_response(array('answer' => '$1')));
     }
@@ -225,7 +225,7 @@ public function test_classify_response_currency() {
                 new question_classified_response(14, '$100', 0)),
                 $num->classify_response(array('answer' => '$100')));
         $this->assertEqual(array(
-                new question_classified_response(13, '1,332', 0.8)),
-                $num->classify_response(array('answer' => '1,332')));
+                new question_classified_response(13, '1 332', 0.8)),
+                $num->classify_response(array('answer' => '1 332')));
     }
 }