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Comment by bmitc | Hacker News Reader

I like Racket's way of handling them, to a degree. Each of {}, [], and () are interchangeable, and the use of [] is mostly down to convention. For example, it is often used in let bindings:

    (define x
      (let ([a 1]
            [b 2])
          (+ a b)))

By to a degree, I would actually prefer if the convention was enforced.

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The convention is enforced in Clojure. [] for bindings, {} for maps.

It is not a convention in Clojure. (), [], {}, #{} represent different data structures.

It's really just syntactic sugar, so I would agree with the statement that the convention is being enforced.

You get different data structures. I.e. printing #{ 1 1 2 2 } prints #{ 1 2 } whereas [ 1 1 2 2 ] prints [ 1 1 2 2].

Not exactly, it uses square brackets for vectors sometimes and curly brackets for maps sometimes, yet other times it uses square brackets for maps:

  (let [a 1 b 2] (+ a b))

Instead of:

  (let {a 1 b 2} (+ a b))

(I think my map notation may be wrong, I always just bounce off Clojure so I'm bound to make mistakes).

I quite like how fennel handles it as well, {} for standard lua tables and [] for arrays, but [] stands to define variables in a let binding. Of course this comes from Lua's quirks, but its a nice, sane way to handle it.

This is an old feature of some Scheme implementations. There are also books where the Scheme code is written this way, IIRC.

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