[ww520]

What about using scope environments and variable binding? For lambda calculus, variable binding (of the single variable x) in an environment (the current application of lambda) is a fundamental part of it anyway.

A scope environment gives you a place to name "things". "Things" can be functions. It's just a name-value map. You create a local scope environment for every function invocation. You can bind things (value or functions) to names in the local environment. Then you can refer to "things" by their names, like calling a function using its name.

Parent scope environments can be nested in the local scope when the function is called. A search on a name not found on the current scope can be delegated to the parent scope, so that functions defined and named in outer scope can be referenced in inner scope.

Recursive call is not a problem for named function since you can look up the function by name. It becomes a problem for anonymous function (lambda) since it can't be looked by name. For that you can introduce a special name like "_lamb" for it. Upon entry of a function, you bind the current function to the name in the current environment. A reference to it would call the current function again. e.g. _lamb(). You can even have a special name "_parent" to bind to the parent environment. In that case you can call the anonymous parent function. E.g. _parent._lamb()

Function calling and recursive function have nothing to do with OO or Java/Python/Ruby. It has everything to do with name, binding, scope, and environment.