The Pyret Programming Language

Post by Mikeb85 » Sun, Aug 22, 2021, 2:14 PM UTC

Maksadbek wrote: post #55

The syntax is pretty much like Python and ruby: “end” to declare end of block statements and colon to start a block statement. But why to use “fun” to declare a function when “def” could be used. The same in other languages: function, func, fun, fn, etc.

Post by dTal » Sun, Aug 22, 2021, 2:25 PM UTC

srfsrvsr wrote: post #91

dTal wrote: post #88

I was excited that Pyret, which I was previously familiar with as a Racket #lang, had evidently gained enough independence to warrant its own website that does not even mention Racket. What a vindication of the #lang system! Then I read this: "Ultimately, Racket’s #lang facilities, though designed to create new languages—and a great prototyping ground for Pyret—proved to not be quite enough to support a language crea…

Is #lang really Racket's USP? I vaguely get that the idea is an extension of the Unix "shebang" convention to files which define modules. It might be preferable to a system based on file extensions or file associations (it's certainly less brittle). I guess the question is whether it's better than directives of the form "import(lang, file)", in other words, explicitly naming the interpretation language for each file…

Post by justinpombrio » Sun, Aug 22, 2021, 2:38 PM UTC

Waterluvian wrote: post #76

piperswe wrote: post #60

Earlier quoted context omitted.

I haven't used doctests in Python, but I have in Rust. It really helps that any code blocks in a docstring is a doctest by default, so they ensure that examples in your documentation stay evergreen. It's nice to know that if there's a code example in documentation, it will compile and run properly and hasn't been broken.

Practically speaking how useful are the Rust doctests? I thought they looked like a genius idea but I don’t get how they work 95% of the time when examples don’t come with all the plumbing required to make valid state for a function to actually work on.

Post by epidemian » Sun, Aug 22, 2021, 2:47 PM UTC

IshKebab wrote: post #89

skrishnamurthi wrote: post #78

Earlier quoted context omitted.

I've used rationals by default in Racket/Scheme for literally 3+ decades now. It's fine. Dart is trying to be an industrial-strength language. We're trying to create an awesome initial programming experience. To the beginner, those denominators are nowhere near as much of a problem as "numbers" that don't make sense. But we draw limits. Did you try the `sin(pi / 6)` example? You'll find that Pyret produces a rather i…

I'm a bit dubious that magic stuff like this really makes anything easier. It's like JavaScript's truthiness and type coersion. It's trying to be friendly and work most of the time, but in reality it is more complex because now you have to remember a whole set of rules about how exactly the magic behaves.

  ~0.49999999999999994

  Reading this expression errored:
  
  num-sin(PI / 6) == 1 / 2
  
  The == and / operations are at the same grouping level. Add parentheses to group the operations, and make the order of operations clear.

  Attempted to compare a Roughnum to an Exactnum for equality, which is not allowed:
  
  The left side was:
  
  ~0.49999999999999994
  
  The right side was:
  
  0.5
  
  Consider using the within function to compare them instead.

Post by dTal » Sun, Aug 22, 2021, 3:01 PM UTC

adsfsdfdsg wrote: post #95

dTal wrote: post #94

Earlier quoted context omitted.

#lang is much more than shebangs. Racket #langs are implemented on top of Racket - they can be nothing more than alternative syntaxes, or they can have different semantics (written in Racket). This has the effect of rendering different Racket #langs interoperable within a project. This is wildly powerful - someone reimplemented Python entirely as a #lang, for instance, which meant that Racket could use (pure) Python…

I understand all that. You don't seem to have understood my comment, which was asking questions about the suitability/fitness of the "#lang" mechanism, rather than questioning the idea of polyglot code on top of Racket. I guess it seems to me like it hasn't been established whether the "#lang" mechanism is a brilliant invention, or something cheesy. My initial reaction is that it seems cheesy.