Made me feel like I understand monads finally...will read again in a couple days when I inevitably forget.
Out of curiosity, does this post help it stick any? https://philipnilsson.github.io/Badness10k/posts/2017-05-07-...
Haskell, Reverse Polish Notation, and Parsing
11–14 of 14 posts
Re: Haskell, Reverse Polish Notation, and Parsing
#12Agreed that RPN (and stack machines) are beautiful and underappreciated. Unfortunately, it's for a relevant reason that I have to push back against the author's newfound love of recursion. Like everyone else I had the same brain-exploding moment when I realized that recursion was possible and how if forced me to re-think what functions were capable of, but now that I'm old and ornery I'm of the Hot Take that recursio…
If I have to traverse a tree, then recursion is more natural to me. With a loop you’ll have to manually use a stack (it’s fine, but more error prone). For lists, I rarely write loops or recursion. It’s mostly folds and maps.
For sure. Data structures and call graphs like to converge, so when designing a data model, you are actually designing the (most natural) program flow too.
Re: Haskell, Reverse Polish Notation, and Parsing
#13I've always felt like RPN is a really powerful lesson in how subtly redefining the semantics of a problem can make it suddenly much easier to solve. My personal struggle with functional programming is how difficult I find it to be iterative. I've very frequently backed myself into a corner and ended up having to rewrite everything, whereas in C, even when I miss badly on the architecture, I'm still usually able to re…
I found writing in Lisp was liberating, as everything can be reused into a bigger program.
And Lisp is a functional programming language. It is also a programmable programming language, so you can even extend its syntax.
I am interested in your struggle. I want to know what is really difficult about functional programming for a learner.
Re: Haskell, Reverse Polish Notation, and Parsing
#14Agreed that RPN (and stack machines) are beautiful and underappreciated. Unfortunately, it's for a relevant reason that I have to push back against the author's newfound love of recursion. Like everyone else I had the same brain-exploding moment when I realized that recursion was possible and how if forced me to re-think what functions were capable of, but now that I'm old and ornery I'm of the Hot Take that recursio…
If I have to traverse a tree, then recursion is more natural to me. With a loop you’ll have to manually use a stack (it’s fine, but more error prone). For lists, I rarely write loops or recursion. It’s mostly folds and maps.
I feel like this is a common enough pattern with well-known translations from one form to the others, that a compiler might optimize it one way or the other. Or is it still too high-level for even modern awesome compilers/interpreters?