Tidy comments and change input comparison.

question.php

@@ -150,8 +150,8 @@ class qtype_stack_question extends question_graded_automatically_with_countback
 
     /**
      * The next three fields cache the results of some expensive computations.
-     * The chache is only vaid for a particular response, so we store the current
-     * response, so that we can clearn the cached information in the result changes.
+     * The chache is only valid for a particular response, so we store the current
+     * response, so that we can learn the cached information in the result changes.
      * See {@link validate_cache()}.
      * @var array
      */
@@ -201,7 +201,7 @@ class qtype_stack_question extends question_graded_automatically_with_countback
 
     /**
      * @return bool do any of the inputs in this question require the student
-     *      validat the input.
+     *      validate the input.
      */
     protected function any_inputs_require_validation() {
         foreach ($this->inputs as $name => $input) {
@@ -467,7 +467,6 @@ class qtype_stack_question extends question_graded_automatically_with_countback
      */
     public function get_input_state($name, $response, $rawinput=false) {
         $this->validate_cache($response, null);
-
         if (array_key_exists($name, $this->inputstates)) {
             return $this->inputstates[$name];
         }
@@ -715,7 +714,6 @@ class qtype_stack_question extends question_graded_automatically_with_countback
      */
     protected function get_prt_input($index, $response, $acceptvalid) {
         $prt = $this->prts[$index];
-
         $prtinput = array();
         foreach ($prt->get_required_variables(array_keys($this->inputs)) as $name) {
             $state = $this->get_input_state($name, $response);

stack/input/inputbase.class.php

@@ -581,7 +581,7 @@ abstract class stack_input {
 
         if (!$valid) {
             $status = self::INVALID;
-        } else if ($this->get_parameter('mustVerify', true) && $validator != $this->contents_to_maxima($contents)) {
+        } else if ($this->get_parameter('mustVerify', true) && !($validator === $this->contents_to_maxima($contents))) {
             $status = self::VALID;
         } else {
             $status = self::SCORE;

stack/potentialresponsenode.class.php

@@ -139,7 +139,6 @@ class stack_potentialresponse_node {
         if ($this->required_atoptions() && !$this->process_atoptions()) {
             $ncasopts = $this->atoptions;
         }
-
         $at = new stack_ans_test_controller($this->answertest, $nsans, $ntans, $options, $ncasopts);
         $at->do_test();
 
@@ -190,7 +189,6 @@ class stack_potentialresponse_node {
         }
 
         $results->add_trace($at->get_trace());
-
         return $resultbranch['nextnode'];
     }