Haskelite is a step-by-step interpreter for a subset of Haskell inspired by Pythontutor and Lambda lessons.
Go ahead and type in definitions and an expression and hit Evaluate to run them step-by step. Or you may start by choosing an example: recursive factorial; sum of squares; removing duplicates; checking primes; list reverse; Collatz sequence; insertion sort; binary conversion; right and left folds; infinite lists; Fibonnacci numbers; insert into a BST; flatten a BST; expression evaluator; expression compiler.
Haskelite is open-source software; please visit the Github page.