Hacker News: lpil

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Wed, 07 Oct 2026 09:29:53 +0000

No AST was ever used for that. Printing algebra was used in the past, and the new Erlang binary and textual generators both work by appending to a buffer. Your assertion that we need an AST has never been correct. From my point of view it would be wasteful and slow for the compiler to construct this AST just to then consume it to push bytes to a buffer.

RE punctuation, the book-keeping required for the binary format is no less work than for the textual format. All these formats are similarly easy to implement, though the ones that are not human readable are more challenging to debug.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Wed, 07 Oct 2026 09:21:18 +0000

Right, and I’m explaining that my multiple years of experience teaching and helping newcomers that an expectation of similarity to Rust frequently results in difficulty, and that it is beneficial to downplay any perceived link.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 21:20:42 +0000

The old one had an inferior implementation, but that is unrelated to the output format. We also have a new Erlang source code generator that is used predominantly in the compiler test suite, and it too is superior.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 21:17:49 +0000

This shows only the base syntax and has nothing of the language functionality, so is incapable of showing overlap between the languages.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 21:15:11 +0000

Yes, exactly my point! Being a Rust user doesn’t mean you are going to prefer or even understand Gleam.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 17:28:45 +0000

LFE used to compile to core Erlang, but it now also compiles to abstract forms.

https://github.com/lfe/lfe/blob/387d0aa1092bdda0ca17481869e8...

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 17:21:53 +0000

The title says it no longer compiles to Erlang source. That's true, it now compiles to an IR of the Erlang compiler.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 16:57:29 +0000

Aye, I am saying that jumping from Rust to Gleam isn't easy because the languages are so different. "How do I do X in Gleam like I would in Rust" is one of the most common categories of support question from newcomers who assumed they were similar.

It can take a moment to understand that things are done quite differently in the two languages due to being so different: https://gleam.run/frequently-asked-questions/#How-does-Gleam...

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 16:55:12 +0000

The ML family clearly inspired Rust greatly, but the end result is very different.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 16:09:26 +0000

For that sort of compilation target more flexibility is beneficial, so C, Wasm, LLVM IR, Cranelift IR etc are better than Go, Nim, and D in my opinion.

> cross portability/small binaries/fast compiled language which is fast to compile

You don't need native compilation to build fast single file executables for a program, there's ways one can achieve this with Gleam today. Bundling the BEAM into your Gleam application executable with something like Gleepack is one option, and this will produce smaller executables than Go will by default for many applications.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 15:35:29 +0000

It's very possible that I'm misunderstanding you! I'm mostly just saying that Gleam is very unlike Rust, so if you pick it or avoid it for Rust related reasons you may not be making the most informed decision.

The languages that Gleam is most like might be Standard ML, OCaml, Elm, and F#.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 15:09:22 +0000

I think a Rust programmer is more likely to prefer Gleam to Elixir, but I don't think there is much link between Gleam and Rust, and I especially do not thing that Gleam should only be considered over Elixir if you are already a Rust programmer.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 15:07:47 +0000

Surprisingly yes! JavaScript's allocator and garbage collection system is quite well suited to immutable programming.

Rust is a very poor compile target as the compiler is slow and not commonly available, and the aspects of Rust that make it good for humans to write make it a poor choice for compilers to target. With humans the produced code is verified, but with a compiler the compiler is what is to be verified, so the inflexibility of Rust are largely a hindrance compared to other native compilation targets.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 14:57:54 +0000

I don't think that's the case, Rust and Gleam have almost nothing in common beyond having static type systems, and those type systems are very different too.

https://gleam.run/frequently-asked-questions/#How-does-Gleam...

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 14:56:23 +0000

Gleam is a simple functional programming language which leans into static typing , friendly tooling, and a one-way-to-do-it style. You'd want to use it if you enjoy the programming experience it provides.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 14:54:45 +0000

It's a general purpose programming language, like OCaml, Python, or Scheme. It's not intended for any specific business domain.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 14:53:46 +0000

JavaScript is useful in lots of places, and even if one compile target is especially good for in-browser user interfaces that doesn't mean that language is specifically intended for user interface development.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 14:52:25 +0000

Go's garbage collection isn't well suited for an immutable language like Gleam, so the performance would likely be disappointing compared to other targets.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 13:42:56 +0000

Gleam is not ostensibly intended for building user interfaces.

New comment by lpil in "Gleam doesn't compile to Erlang source anymore"

lpil — Tue, 06 Oct 2026 13:41:37 +0000

I don't think your "it is source as you can convert it back into source" argument holds water as all the Erlang formats can be decompiled into Erlang source code, including the final bytecode itself.

I think you're overthinking the cost of compiling to source, and also underestimating how common it is.