aoc2021 VS nom

With only a few small restrictions down from "fully general", I have a brute-force-ish solution in python running in about 15 seconds on my hardware and my input: https://github.com/fizbin/aoc2021/blob/main/aoc24b.py

With day 22, I actually have three different python approaches in my repo; the inclusion/exclusion approach is what I named aoc22c.py.

This sounds vaguely similar to the approach I took on my second python solution, minus one optimization that I used: namely, I determined the maximum allowable value of "z" at the end of each instruction if we were going to end the program with z=0 and used that to throw away states that weren't worth pursuing.

I've implemented that approach, and my code to do so takes less than five seconds on my machine, so I wonder: have you tried this on the sample input? What does it do there?

How about a python translation of my haskell solution?

My solution in my github repo

Here's the more straightforward Monad-based solution, which unfortunately takes well over a minute to run.

Just in case you are not familiar with nom, it is a parser combinator written in Rust. The most basic thing you can do with it is import one of its parsing functions, give it some byte or string input and then get a Result as output with the parsed value and the rest of the input or an error if the parser failed. tag for example is used to recognize literal character/byte sequences.

I may be the only one not familiar, but nom refers to https://github.com/rust-bakery/nom which looks like a pretty handy way to parse binary data in Rust.

Lots of people use nom for their parsing needs, but that's not the only game in town and there other options.

As much as I love nom as well as other parser combinator libraries, regex-based parsers, BNF/EBNF-based parsers, etc. I always end up going back to plain old text-based char-by-char scanners.

I am using nom / nom_locate to build the parser side because I've done a handful of other projects with it, and I plan to use tower-lsp to hook up the language server side.

Look into a parsing library such as https://github.com/rust-bakery/nom

If we were in /r/learnrust I'd have recommended the nom crate for this.

Thanks to the flexibility of [nom](https://github.com/rust-bakery/nom), it is very easy to write your own parser in rust, read [this article](https://github.com/metaworm/luac-parser-rs/wiki/Write-custom-luac-parser) to learn how to write a luac parser

I've been working on an assembler and right now it uses nom. While nom isn't great for error messages, good error messages will be important for this particular assembler (current code), so I've been attempting to use the methods described by Eyal Kalderon in Error recovery with parser combinators (using nom).