rand VS chumsky

Making compatibility promises for distributions means they cannot take advantage of potential advancements in the field.

Defining an error type that is meaningful, portable, and compatible with no-std isn't straightforward. If the std lib's getrandom requires std, then just like that, rand and many other crates won't use it anyway. Using io::Result seems to me to face this challenge.

Some wasm targets can’t generate random numbers at all but in the case of the book because you are using wasm in a browser you can use JS to generate random numbers. I believe there’s a way to get the rand crate to use JS as the backend for generating rand but its a bit more convoluted than the easy one-liner that the book suggests.

rand

This uses rand and xcomplex to handle the mathematics, png to write image files, and dialoguer and indicatif for some pretty prompts and progress bars.

You can often achieve this without any unsafe by putting an assert!() on the length before the hot loop. For example, I got rid of some unsafe in rand that way.

This is a widely used method to map random integers to floating point numbers, but it has the disadvantage of wasting 1 bit of float mantissa precision.

On modern CPUs, its computational advantage over full-precision mapping methods, such as multiplication by a float, is not always clear [1].

[1] https://github.com/rust-random/rand/issues/416

In fact, there are a lot of crates in Rust where in other programming languages, it would be included in the standard library. Examples are regex, random number generators, additional iterator methods, macros for other collections, num traits, loggers, HTTP libraries, error handling, async runtimes, serialization and deserialization, date and time, and many more.

I attempted to use this but was disheartened but the fact that it doesn't statically type node names. Tree Sitter doesn't either but it has much more of an excuse given that it targets C.

https://github.com/lezer-parser/lezer/issues/8

The dev seems mildly hostile to outside involvement too, so I moved on. These days I use Chumsky which is Rust rather than Typescript, but also way more awesome, if you can deal with the often incomprehensible compilation errors at least!

https://github.com/zesterer/chumsky

there’s also chumsky: https://github.com/zesterer/chumsky

We are using technique called parser combinator. And we are using a library chumsky to write parser combinators.

rust-langdev has a lot of libraries for building compilers in Rust. Perhaps you could use these to make your implementation easier, and revisit it later if you want to build things from scratch. I'd suggest logos for lexing, LALRPOP / chumsky for parsing, and rust-gc for garbage collection.

The examples that come with chumsky and the chumsky tutorial and guide all define their parsers using closures.

Parser: https://crates.io/crates/chumsky

chumsky's zero-copy rewrite has reached its first alpha release, and I have migrated my pep-508 parser to it, as suggested in my last announcement.

On my side, nom is still advancing well and a new major version is in preparation, with some interesting work a new GAT based design inspired from the awesome work on chumsky, that promises to bring great performance with complex error types. 2023 will be fun for parser libraries!

I am using chumsky because I like the API, but it doesn't support zero copy at the moment. Although efficiency is good to have, it is not my primary good. This will probably get supported once chumsky implements support for it (see upstream issue).

Checkout https://github.com/zesterer/chumsky or https://github.com/rust-bakery/nom