Structured and unstructured computation...
in one programming language
Mindscript is an experimental programming language that offers a dual system of formal and informal types.
Types constrain the values that an expression can take. However, formal types impose constraints that can be deduced (via computation), while informal types impose inductive constraints which guide the black-box evaluation of an expression (much like our own thought processes are shaped by our observations).
Download MindScript from the Github repo.