i've worked through this article a couple times and his implementation never really sat well with me, the "with nice syntax for monad comprehensions" bit really obfuscates the implementation.
here's python source to a monadic lisp interpreter, which i wrote to follow along the paper "monad transformers and modular interpreters" [1]. i think this is a much simpler implementation of python monads than provided in the ValuedLessons article. https://github.com/dustingetz/monadic-interpreter
Study of this implementation will teach you why nobody actually uses monads in python for non-toy projects. A literal port of this code to clojure would feel so much more idiomatic and not hacky at all.
here are some smaller code dumps demonstrating the fundamental concepts to that monadic lisp interpreter:
I think the point of this article is to make a "nice" syntax for monadic operations in python (i.e. avoiding all the lambdas and extra parens in the "bind(mx, lambda x: my)"/"mx >> (lambda x: my)" pattern), no matter how unclear and non-pedagogical the implementation ends up.
here's python source to a monadic lisp interpreter, which i wrote to follow along the paper "monad transformers and modular interpreters" [1]. i think this is a much simpler implementation of python monads than provided in the ValuedLessons article. https://github.com/dustingetz/monadic-interpreter
Study of this implementation will teach you why nobody actually uses monads in python for non-toy projects. A literal port of this code to clojure would feel so much more idiomatic and not hacky at all.
here are some smaller code dumps demonstrating the fundamental concepts to that monadic lisp interpreter:
http://www.dustingetz.com/2012/10/02/reader-writer-state-mon... http://www.dustingetz.com/2012/10/07/monads-in-python-identi...
[1] http://haskell.cs.yale.edu/wp-content/uploads/2011/02/POPL96...