Conditions can now be more than just class names

Author: sagikazarmark

spec/ClassDiscoverySpec.php

@@ -30,12 +30,42 @@ function it_registers_a_class_with_a_condition()
     {
         $this->reset();
 
-        $this->register('class1', 'spec\Http\Discovery\ClassToFind', 'invalid');
+        $this->register('class1', 'spec\Http\Discovery\ClassToFind', false);
         $this->register('class2', 'spec\Http\Discovery\AnotherClassToFind', 'spec\Http\Discovery\TestClass');
 
         $this->find()->shouldHaveType('spec\Http\Discovery\AnotherClassToFind');
     }
 
+    function it_registers_a_class_with_a_callable_condition()
+    {
+        $this->reset();
+
+        $this->register('class1', 'spec\Http\Discovery\ClassToFind', false);
+        $this->register('class2', 'spec\Http\Discovery\AnotherClassToFind', function() { return true; });
+
+        $this->find()->shouldHaveType('spec\Http\Discovery\AnotherClassToFind');
+    }
+
+    function it_registers_a_class_with_a_boolean_condition()
+    {
+        $this->reset();
+
+        $this->register('class1', 'spec\Http\Discovery\ClassToFind', false);
+        $this->register('class2', 'spec\Http\Discovery\AnotherClassToFind', true);
+
+        $this->find()->shouldHaveType('spec\Http\Discovery\AnotherClassToFind');
+    }
+
+    function it_registers_a_class_with_an_invalid_condition()
+    {
+        $this->reset();
+
+        $this->register('class1', 'spec\Http\Discovery\ClassToFind', new \stdClass);
+        $this->register('class2', 'spec\Http\Discovery\AnotherClassToFind', true);
+
+        $this->find()->shouldHaveType('spec\Http\Discovery\AnotherClassToFind');
+    }
+
     function it_resets_cache_when_a_class_is_registered()
     {
         $this->reset();

src/ClassDiscovery.php

@@ -31,7 +31,7 @@ public static function register($name, $class, $condition = null)
 
         static::$classes[$name] = [
             'class'     => $class,
-            'condition' => $condition ?: $class,
+            'condition' => isset($condition) ? $condition : $class,
         ];
     }
 
@@ -50,7 +50,7 @@ public static function find()
         }
 
         foreach (static::$classes as $name => $definition) {
-            if (class_exists($definition['condition'])) {
+            if (static::evaluateCondition($definition['condition'])) {
                 static::$cache = $definition['class'];
 
                 return new $definition['class'];
@@ -59,4 +59,25 @@ public static function find()
 
         throw new NotFoundException('Not found');
     }
+
+    /**
+     * Evaulates conditions to boolean
+     *
+     * @param mixed $condition
+     *
+     * @return boolean
+     */
+    protected static function evaluateCondition($condition)
+    {
+        if (is_string($condition)) {
+            // Should be extended for functions, extensions???
+            return class_exists($condition);
+        } elseif (is_callable($condition)) {
+            return $condition();
+        } elseif (is_bool($condition)) {
+            return $condition;
+        }
+
+        return false;
+    }
 }