Create some new standard library modules

modules/collection/src/main/kotlin/io/smnp/ext/CollectionModule.kt

@@ -0,0 +1,9 @@
+package io.smnp.ext
+
+import org.pf4j.Extension
+
+@Extension
+class CollectionModule : LanguageModuleProvider("smnp.collection") {
+   override fun files() = listOf("list.mus")
+   override fun dependencies() = listOf("smnp.lang")
+}

modules/collection/src/main/resources/list.mus

@@ -0,0 +1,15 @@
+function flatten(...lists: list) {
+    return _flatten(lists as list ^ _flatten(list, []), []);
+}
+
+function _flatten(list: list, output: list) {
+    list as element ^ {
+        if (typeOf(element) == "list") {
+            output = _flatten(element, output);
+        } else {
+            output = output + [element];
+        }
+    }
+
+    return output;
+}