Initial data commit

Task/Call-a-function/Dyalect/call-a-function-9.dyalect

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+//Built-in functions are regular functions from an implicitly imported "lang" module
+//There is no actual difference between these functions and user-defined functions
+
+//You can however write a function that would check if a given function is declared in "lang" module:
+func isBuiltin(fn) =>
+    fn.Name is not nil && fn.Name in lang && lang[fn.Name] == fn
+
+//Usage:
+func foo() { } //A user-defined function
+print(isBuiltin(foo)) //Prints: false
+print(isBuiltin(assert)) //Prints: true