lalrpop VS logos

And some related parser tools: - https://github.com/kevinmehall/rust-peg - https://github.com/pest-parser/pest - https://github.com/lalrpop/lalrpop

lalrpop

Rust is a very nice langage for implementing compilers, and has a nice ecosystem for it (logos, rust-peg, lalrpop, astmaker -- this one is mine --, etc...).

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.

Hi! For one of my projects I am currently using lalrpop (https://github.com/lalrpop/lalrpop/tree/master/doc/calculator/src), which is far from complete, but has the basic syntax I was looking for. I took some examples and worked around some lexer stuff but I’m currently happy with it. If you use it and have Intellij stuff installed, you can also use a plug-in for highlighting and SOMETIMES error checking. Otherwise, even VSCode had a great plug-in for highlighting!

How would you compare and contrast this with, say, lalrpop?

lalrpop is great. It's a completely different approach from nom, but for parsing a programming language, I would at least consider it. RustPython uses it.

I presume LALRPOP handles left recursion just fine.

I wanted to share an experimental side project I have been working on for some time. I constantly use commands like `jq` and `yq` for processing structured data in my day job and I was curious if a similar idea could be applied to images.

Another goal of mine was to get some exposure to with rust. I discovered the LALRPOP parser generator which really helped moved the project along (https://github.com/lalrpop/lalrpop)

The key point here is that we are going to depend on the lalrpop library to generate the parser based on the formal grammar we define. Note that we have it as part of the [build-dependencies] section and we only depend on a tiny utility crate called lalrpop-util at runtime. The reason for that is the main lalrpop "magic" would happen during the crate compilation (in the build.rs file) when lalrpop would generate the deterministic pushdown automaton based on our grammar. The code generation logic is not required to be part of our interpreter, we only need a few utility methods from the lalrpop-util for the automaton to operate. You might have noticed that we also enable the lexer feature of lalrpop, because we are going to use lexer provided by lalrpop as well (please refer to the Part I if you do not know what the lexer is).

This is mighty impressive! I've been trying to get some motivation for the mythical rewrite of the proc macro in Logos, and this might just do it for me :D. I'll have a proper look later today and see if any of your findings have something that can be generalized. Also really surprised to see aarch64 doing better than x86_64 since the latter is what I've been optimizing for!

Rust is a very nice langage for implementing compilers, and has a nice ecosystem for it (logos, rust-peg, lalrpop, astmaker -- this one is mine --, etc...).

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.

Thanks! For compile times you might find the CLI version that Andrew Hickman contributed useful, it's undocumented still mostly I fear but shouldn't be hard to use, see original PR: https://github.com/maciejhirsz/logos/pull/248

For my lexer generation purposes, I tend to use https://github.com/maciejhirsz/logos, as it not only generates an easy to use lazy lexer, but the result is also exceptionally fast!

Hi, I'm using rowan to create a parser and want to print more useful error messages with position in the text/file. I'm using logos (https://crates.io/crates/logos) to generate the lexer. Is there a way to get the starting and ending positions of a SyntaxToken? If not I thought of adding my own wrapper struct around the SyntaxTokens.

Is there a way for a lexer created with the logos crate (https://crates.io/crates/logos) to get the starting and ending positions for the tokens?

I wouldn't recommend Logos at this point. This recent bug is quite nasty and seems easy to hit, and the maintainer is unresponsive. Last commit was half a year ago. At this point I consider Logos abandonware, though it would be great if its development continued, or if it were forked.

logos uses "ridiculously fast".