@hackage / s-cargot-letbind

This module allows let bindings to be introduced into the S-Expression syntax.

For example, instead of:

   (concat (if (enabled x) (+ (width x) (width y)) (width y))
           " meters")

this can be re-written with let bindings:

   (let ((wy    (width y))
         (wboth (+ (width x) wy))
         (wide  (if (enabled x) wboth wy))
        )
     (concat wide " meters"))

As S-expressions grow larger, let-binding can help readability for those expressions. This module provides the discoverLetBindings function that will convert an S-expression into one containing let-bound variables, and the inverse function letExpand which will expand let-bound variables back into the expression.