Parameters and exception swallowing.

README.md

@@ -103,6 +103,31 @@ Upon running the code above, the control and trials are all executed. Using Jour
 
 Once we've checked our data, and we're confident that our trial is equivalent (or better!) to our control code, we'll replace the experiment with that implementation.
 
+## Parameters
+
+Your count might not be useful without additional parameters. Don't worry, we've got you covered.
+
+```php
+->run($param, $secondParam, $more);
+```
+
+or
+
+```php
+->result($param, $secondParam, $more);
+```
+
+You can pass parameters to the `run()` or `result()` methods, and the parameters will be provided to both the control and trial callbacks on execution. Simple, right?
+
+## Chance it!
+
+Your experiments might be a little weighty. You might not want to run them all the time. Provide a % chance parameter to alter the chance that an experiment will run.
+
+```php
+$lab->experiment('foo')
+    ->chance(50)...;
+```
+
 ## Journals
 
 Journals are assigned to a Laboratory, and are used to report on the result of experiments. You'll (hopefully soon) find a bunch of journals on packagist, or you can create your own.

src/Execution.php

@@ -33,18 +33,27 @@ class Execution
      */
     protected $match = false;
 
+    /**
+     * Thrown exception.
+     *
+     * @var boolean
+     */
+    protected $exception;
+
     /**
      * Construct a new execution.
      *
-     * @param mixed   $value
-     * @param float   $time
-     * @param boolean $match
+     * @param mixed      $value
+     * @param float      $time
+     * @param boolean    $match
+     * @param \Exception $exception
      */
-    public function __construct($value, $time, $match = false)
+    public function __construct($value, $time, $match = false, $exception = null)
     {
-        $this->value = $value;
-        $this->time  = (float) $time;
-        $this->match = (boolean) $match;
+        $this->value     = $value;
+        $this->time      = (float) $time;
+        $this->match     = (boolean) $match;
+        $this->exception = $exception;
     }
 
     /**
@@ -77,6 +86,16 @@ public function isMatch()
         return $this->match;
     }
 
+    /**
+     * Get a thrown exception.
+     *
+     * @return boolean
+     */
+    public function getException()
+    {
+        return $this->exception;
+    }
+
     /**
      * Retrieve the execution in JSON string format.
      *

src/Experiment.php

@@ -230,6 +230,16 @@ public function shouldRun()
         return rand(0, 100) <= $this->chance;
     }
 
+    /**
+     * Get the experiment parameters.
+     *
+     * @return array
+     */
+    public function getParams()
+    {
+        return $this->params;
+    }
+
     /**
      * Execute the experiment within the laboratory.
      *

src/Intern.php

@@ -2,6 +2,7 @@
 
 namespace Scientist;
 
+use Exception;
 use Scientist\Matchers\Matcher;
 
 /**
@@ -39,7 +40,11 @@ public function run(Experiment $experiment)
      */
     protected function runControl(Experiment $experiment)
     {
-        return $this->executeCallback($experiment->getControl(), $experiment->getMatcher());
+        return $this->executeCallback(
+            $experiment->getControl(),
+            $experiment->getParams(),
+            $experiment->getMatcher()
+        );
     }
 
     /**
@@ -55,7 +60,12 @@ protected function runTrials(Experiment $experiment, Execution $control)
         $executions = [];
 
         foreach ($experiment->getTrials() as $name => $trial) {
-            $executions[$name] = $this->executeCallback($trial, $experiment->getMatcher(), $control);
+            $executions[$name] = $this->executeCallback(
+                $trial,
+                $experiment->getParams(),
+                $experiment->getMatcher(),
+                $control
+            );
         }
 
         return $executions;
@@ -65,13 +75,15 @@ protected function runTrials(Experiment $experiment, Execution $control)
      * Execute a callback and record an execution.
      *
      * @param callable                    $callable
+     * @param array                       $params
      * @param \Scientist\Matchers\Matcher $matcher
      * @param \Scientist\Execution|null   $control
      *
      * @return \Scientist\Execution
      */
     protected function executeCallback(
         callable  $callable,
+        array     $params,
         Matcher   $matcher,
         Execution $control = null
     ) {
@@ -80,8 +92,18 @@ protected function executeCallback(
          * recorded timestamps, so that we can calculate
          * the execution time of the code.
          */
+        $exception = null;
         $before = microtime(true);
-        $value = call_user_func($callable);
+        if ($control) {
+            try {
+                $value = call_user_func_array($callable, $params);
+            } catch (Exception $ex) {
+                $value = null;
+                $exception = $ex;
+            }
+        } else {
+            $value = call_user_func_array($callable, $params);
+        }
         $after = microtime(true);
 
         /**
@@ -92,7 +114,8 @@ protected function executeCallback(
         return new Execution(
             $value,
             $after - $before,
-            $matcher->match($value, $compare)
+            $matcher->match($value, $compare),
+            $exception
         );
     }
 }

src/Laboratory.php

@@ -83,9 +83,12 @@ public function runExperiment(Experiment $experiment)
         if ($experiment->shouldRun()) {
             $result = $this->getResult($experiment);
             return $result->control()->getValue();
-        } else {
-            return call_user_func($experiment->getControl());
         }
+
+        return call_user_func_array(
+            $experiment->getControl(),
+            $experiment->getParams()
+        );
     }
 
     /**
@@ -99,6 +102,7 @@ public function getResult(Experiment $experiment)
     {
         $result = (new Intern)->run($experiment);
         $this->reportToJournals($experiment, $result);
+
         return $result;
     }