[klibertp]

I'm not sure I like this syntax. It's unfamiliar both to lispers and "mainstreamers". The former will be irritated with { and commas, the latter will try to insert : everywhere.

I read an interview with Rich Hickey where he said that adding these three syntax constructs reduced cognitive burden on programmers. He meant () for lists, [] for vectors and {} for hashes.

I should implement it in Racket and just see how it feels.

[notimetorelax]

There was a discussion on the mailing list concerning colon in maps, here's the JIRA issue [1]. IIRC it was kind of decided to let it die, but maybe someone will implement it.

Personally I think that differentiating between lists and maps is important and the way Clojure does it (as well as JSON) is quite easy to write and read. FWIW example given by bitcracker is broken because there's no way to understand what does the following mean:

   (rels (author 9) (comments (5 12 17 20)))

The outermost element is it a list or a map?

[1] http://dev.clojure.org/jira/browse/CLJ-899