- Added a new getExtensionInstanceOf() method in Compiler

src/Compiler.php

@@ -158,6 +158,19 @@ class Compiler
         return $this->extensionList[$tokenName];
     }
 
+    public function getExtensionInstanceOf(string $class) : Extension\Extension
+    {
+        foreach(array_reverse($this->extensionList) as $ext) {
+            if ( is_a($ext, $class, false) ) {
+                return $ext;
+            }
+        }
+
+        throw new \InvalidArgumentException(<<<MSG
+            Requested extension instance of `$class` could not be found from loaded Picea compiler's extension.
+        MSG);
+    }
+
     public function exportFunctions() : void
     {
         static $caching = [];