Add new modules to standard library

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

@@ -4,6 +4,6 @@ import org.pf4j.Extension
 
 @Extension
 class CollectionModule : LanguageModuleProvider("smnp.collection") {
-   override fun files() = listOf("list.mus")
+   override fun files() = listOf("list.mus", "map.mus")
    override fun dependencies() = listOf("smnp.lang")
 }

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

@@ -12,4 +12,34 @@ function _flatten(list: list, output: list) {
     }
 
     return output;
+}
+
+extend list as this {
+    function toFlat() {
+        return flatten(this);
+    }
+
+    function contains(value) {
+        return (this as item ^ item % item == value).size > 0;
+    }
+
+    function join(separator: string = ", ") {
+        output = ""
+        this as (item, index) ^ {
+            output = output + item;
+            if (index < this.size - 1) {
+                output = output + separator;
+            }
+        }
+
+        return output;
+    }
+
+    function isEmpty() {
+        return this.size == 0;
+    }
+
+    function isNotEmpty() {
+        return not this.isEmpty();
+    }
 }

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

@@ -0,0 +1,21 @@
+extend map as this {
+    function containsKey(key) {
+        return this.keys.contains(key);
+    }
+
+    function containsValue(value) {
+        return this.values.contains(value);
+    }
+
+    function contains(key, value) {
+        return (this as (v, k) ^ v % (k == key) and (v == value)).size > 0;
+    }
+
+    function isEmpty() {
+        return this.size == 0;
+    }
+
+    function isNotEmpty() {
+        return not this.isEmpty();
+    }
+}