Liskell – Haskell Semantics with Lisp Syntax [pdf] | Hacker News Reader

Liskell – Haskell Semantics with Lisp Syntax [pdf]

clemens.endorphin.org

73 pointstodsacerdoti25 comments

The other way round, a Haskell on top of a Lisp, in production today: https://github.com/coalton-lang/coalton/

> Coalton is an efficient, statically typed functional programming language that supercharges Common Lisp.

Presentation this year on the ELS: https://www.youtube.com/watch?v=of92m4XNgrM

I'm not sure I'd say this is "the other way around"; Coalton strives to implement Haskell or ML-adjacent semantics (in the type system, for example) with Lisp syntax. "With" here meaning that it is both implemented in and written with Lisp syntax.

Edit: I think I see what you mean now. Lisp backend vs Haskell backend.

Anyway, Coalton is a joy to use and IMO a breath of fresh air in CL. It's quite easy start using as a library; go all-in or only use it in specific parts of the code. It's great to be able to choose between (or intermix)the flexibility of CL and the guarantees of a statically typed language (as well as some nice performance boosts with arguably less work). Some aspects are still young (some of the standard library, ecosystem, editor support), but it's quite thoughtfully crafted and I'm excited to see where it goes.

>Coalton strives to implement Haskell or ML-adjacent semantics (in the type system, for example) with Lisp syntax. "With" here meaning that it is both implemented in and written with Lisp syntax.

Not exactly. Coalton brings ML-style strong typing to Common Lisp. But Coalton code is also Lisp code.

The backend, thus, is Common Lisp, and it is available at all times, thus leveraging all its power.

I think I meant the same thing, but you said it much more clearly, thanks!

I will prempt the comment that always shows up in discussions of this kind:

No. Typeclasses do not replace proper macros. Go home, you are drunk.

Another argument I've often heard is that laziness largely obviates macros. Personally, I agree that this is often true—but not always, and that last bit is where Lisp-style macros would be really nice.

(^^ edited based on one of the responses below.)

do you know of a post or something you could point to that elaborates that argument? interested because I'm having trouble coming up with the line of reasoning on my own

This is not a direct response to the question of how laziness obviates the need for macros, but it mentions some specific relevant cases:

https://augustss.blogspot.com/2011/05/more-points-for-lazy-e...

I'm having trouble finding anything concrete online (other than people simply repeating the folk wisdom) other than control flow operators, which are implemented as normal functions in Haskell (i.e. including custom control flow operators).[0] Although, one Reddit comment[1] did also mention typeclasses as obviating other types of macros, so I've edited my earlier comment accordingly.

[0] https://www.reddit.com/r/haskell/comments/5xge0v/comment/deh...

[1] https://www.reddit.com/r/haskell/comments/1929xn/comment/c8k...

The venerable master Qc Na was walking with his student, Anton. Hoping to prompt the master into a discussion, Anton said "Master, I have heard that objects are a very good thing - is this true?" Qc Na looked pityingly at his student and replied, "Foolish pupil - objects are merely a poor man's closures."

Chastised, Anton took his leave from his master and returned to his cell, intent on studying closures. He carefully read the entire "Lambda: The Ultimate..." series of papers and its cousins, and implemented a small Scheme interpreter with a closure-based object system. He learned much, and looked forward to informing his master of his progress.

On his next walk with Qc Na, Anton attempted to impress his master by saying Master, I have diligently studied the matter, and now understand that objects are truly a poor man's closures." Qc Na responded by hitting Anton with his stick, saying "When will you learn? Closures are a poor man's object."

At that moment, Anton became enlightened.

Some fun code examples in Ruby: https://medium.com/@citizen428/of-closures-and-objects-e9507...

I'll get in trouble if I show up this drunk at this hour, can't I just bolt on a templating system?

There's also Hackett: Haskell with Racket's syntax and macro system, by Alexis King

To save folks a search:

github repo: https://github.com/lexi-lambda/hackett

Documentation: https://lexi-lambda.github.io/hackett/

It is time for Rusted !!!

Rust semantics with D syntax (garbage collector is a bonus).

Didn’t D get an ownership model, a la Rust’s affine types, relatively recently?

I don't think so, but they are working towards it.

The big news is that this will cover the GC cases too, not only the manual memory management.

How does it compare to Shen?

https://shenlanguage.org

Kinda hard to tell when I can’t find a single example of the language on its website.

really, I did't realize there was no link

https://shen-language.github.io

Ok well that at least has examples of the syntax. But not a single example of actually using the language to do anything. That is, no examples of actual code.

It took a while to click through a link to an actual implementation on github, which had some test examples. None of which were documented.

So idk? I'm not going to buy the ebook for $41 to find out.

So to answer your original question: Liskell, despite being 13 years old and unmaintained, does actually have an accessible document that _explains what it is_.

I was told Lisp didn’t have syntax.

It has minimal, very regular, syntax.

Which is a strength in some aspects, and, although many lispers will never admit it, a weakness in others.

Date of publication is from 2007.

Savior of the universe.

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