[nu11ptr]

I'm just saying a compiler is a program, and while the more important things are heavy algorithm related, supporting libraries like those for error handling, etc. all still matter and add up. No problem if you disagree - just my perspective. This isn't so much an objective thing as it is a personal opinion.

[brmgb]

Personally, it’s not so much that I disagree. It’s more that Ocaml has a top notch ecosystem for compiler writing. That’s probably by far its strongest point with library like Menhir having few equivalent in different ecosystem.

Not that there is anything wrong with Rust if you are ready to pay the price of having so much low level things to deal with.

[hardwaregeek]

Can you explain what Menhir does better than other parser frameworks? For what it's worth, I'm not a huge fan of parser frameworks. I tend to prefer hand written parsers, either via a combinator library or fully manually.

Rust has a pretty darn good ecosystem too btw. chumsky for parsing, rowan for syntax trees, salsa for incremental computation, miette for errors, inkwell/walrus for code generation.

[arcticbull]

Wow those library recommendations are fantastic, especially Chumsky. Thanks for sharing.

[hardwaregeek]

Yeah chumsky is fantastic, albeit with some rough compile errors and some unsafe. Still my favorite parser library by far and I’ve used a bunch by now.

[brmgb]

It can generate elegant and efficient parsers for LR(1) grammars.

> I tend to prefer hand written parsers, either via a combinator library or fully manually.

That’s common with people used to languages which provide poor parser generators.

[hardwaregeek]

What makes them more elegant than the average parser? How’s the error recovery? Can you parse into high fidelity syntax trees efficiently?

I don’t know of many production compilers that use parser generators

[klodolph]

You use the generated parser as a platform for experimentation.

If you know the language, and you have a bunch of users, and you are writing a parser for it, by all means, write a parser by hand and give it the best error recovery that you can muster. If you are developing a language and want to do a bunch of experiments, it pays dividends to use a parser generator. And then there is the whole space of DSLs and mini-languages you encounter, where beautiful error messages are a nice-to-have, but you would rather ship a generated parser and move on to more important work.

It’s easy to focus on compilers from the perspective of familiar languages like writing compilers for Rust or for OCaml, but you may end up writing a compiler that gets used by a much smaller number of people, for smaller tasks.

[hardwaregeek]

That's great and I agree for these use-cases a parser generator makes sense. But that doesn't answer my question about what makes these parsers particularly elegant. Nor does it seem to be a benefit specific to Mehnir, since any parser generator has the quick iteration speed.

I don't mean to blame you for that; you are answering a question about something that you did not say. But I find it frustrating that Mehnir seems to be cited as this fantastic cornerstone of the OCaml ecosystem when I haven't been presented with a good example of how it's better than any other parser generator. Not just my parent comment (who also decided to cast aspersions on my knowledge), but others in the OCaml community too.

[derriz]

I don’t think so - I’ve written parsers using flex/lex yacc/bison, antlr, a bunch of functional combinator libraries and maybe others I’ve forgotten but now would never consider anything except hand-written recursive descent with an embedded Pratt parser for expressions and precedence.

Simple to write, debug, recover from errors, provide decent error messages, unit test, integrate into build systems, IDEs etc.

I also believe that nearly all the popular compilers these days do something similar - gcc was rewritten a few years ago in this fashion because of the technical benefits I’ve listed above.

[moomin]

I mean, it’s also common with people who value great feedback in their tools.

[59nadir]

> That’s common with people used to languages which provide poor parser generators.

The vast majority of real languages have hand-rolled parsers and there is no real reason they shouldn't.

[foderking]

>That’s common with people used to languages which provide poor parser generators.

lmao