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Comment by salsa_catsup | Hacker News Reader

Is Racket the Lisp where I wanted to write keywords like `foo:` or `:foo`, but they went with something like `'#:foo`, which ruined keyword syntax for me?

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Fear not, you can make `#%top` and `#:app` rewrite `foo:` to `#:foo`.

FWIW choosing `#:foo` over, say, `foo:` was due to backwards compatibility. In Scheme and Racket `foo:` is a legal identifier, so there might have been programs that stopped working, if `foo:` suddenly was a keyword.

I don't know about Racket, but I do know Guile does that and I kind of prefer it as a way to reduce syntax (because the number sign is syntax already for most Lisps as the marker for a vector, and it's also used to bring functions into the symbol namespace in a Lisp-2) by freeing the colon.

Do they do something neat with the colon? I do prefer the shorter keyword syntax, at least in Clojure because of how common they are.

Clojure tends to use them very heavily though, and last I looked it seemed like Racket used more lists (as a matter of community preference, not forced by the language).

Racket's lineage in Scheme is probably the reason it prefers lists over pretty much every other datastructure

Notice that Racket now supports "tree lists".

https://docs.racket-lang.org/reference/treelist.html

Scheme has had all major data structures for quite some years now.

A colon in Guile is just a regular character. For example:

  (define abc:def 3)
  (define :ghi 4)
  (* abc:def :ghi) ; => 12

In Common Lisp a colon is a package separator, with an optional package which defaults to the keyword package if not given.

  (eq :foo keyword:foo) ; => t

I don't know about Clojure or Racket because I don't know much about Clojure or Racket. I know Clojure differs in various ways where syntax is concerned to Common Lisp or Scheme (I do like the idea of using square brackets to visually indicate that a collection of atoms may not represent a function call, I hate the idea of the comma being a whitespace character) and that Racket has different languages (though I don't know what that means in practise).

That said, I don't quite know what to think of your third sentence:

> Clojure tends to use them very heavily though, and last I looked it seemed like Racket used more lists

I suppose them refers to keywords? But Racket uses more lists compared to how much Clojure uses keywords? As lists have more uses than keywords that seems likely, though as I said: I don't know anything about Clojure or Racket apart from Racket once being called PLT Scheme.

Guile keywords use the same #:foo syntax as Racket. The reader can also accept :foo or foo: notation.

https://doc.guix.gnu.org/guile/latest/en/html_node/Keyword-R...

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