polysemy-methodology

polysemy-methodology provides an algebra for domain modelling in polysemy.

A simple program might look something like this:

prog :: Members '[ Input a
                 , Methodology a b
                 , Output b]
prog = input @a >>= process @a @b >>= output @b

That is, this program transforms an Input a into an Output b by way of a Methodology a b that turns a into b. We can then type apply a and b and connect this to main.

If we have a solution readily available, we can consume a Methodology by running one of the interpreters runMethodologyPure or runMethodologySem.

Otherwise, we can use the other interpreters in this package to break the problem down into components or branches and solve each section separately. Each interpreter will produce a new set of Methodologys to be solved.

This allows you to work up a solution to a domain problem backwards, by running the program you intend to solve directly and using holes to guide the requirements.