FLAN and FLANGE

FLAN is a toy functional language realised as a series of evaluators written in C. It supports higher-order functions, simple types, user-defined algebraic datatypes, and strict and lazy evaluation. There is also a simpler first-order strict evaluator. There is no type inference or parametric polymorphism.
FLANGE is FLAN augmented with support for Peter Henderson's ideas about functional geometry. It generates SVG files.
Included are many examples of classical computer science algorithms, expressed in a functional style. Most come out cleanly.
The source code is available at at GitHub.

Gallery of FLANGE images

Fish Cycle Fish Limit H Tree Maze Henderson Fish Convex Hull Closed Path L-Systems