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Thanks for your comment. The idea behind the Lisp reader approach is that custom syntax is used for reading/printing objects of different types, not to demarcate syntactic elements. For example, double quotes are for strings, #P"" will read pathnames, and so on. In Common Lisp, some characters like [ and { are reserved for the user, meaning that no conforming implementation defines a custom syntax based on those characters. And you can define [a b c] to mean (vector a b c), which will build a vector, when executed, to hold the current values of a, b and c. The existing #(a b c) vector syntax is a literal vector that contains symbols. From this point of view, for Clojure, I don't think it is a bad idea to have a short syntax for vectors, set and map literals. But then, those objects are used when representing code, not because it has a real added value but because the visible syntax is a little bit nicer (maybe, maybe not). That IMO complexifies tools that work with code and does not really fulfill a practical purpose. If that was for practical reasons, I think bindings would had been better defined as maps: as far as I know, they seem to fit more naturally than vectors for this task. For example: (let {a 20 b 10} ...)
Somehow when compiling or interpreting the code, you could do "(get symbol env)" where "env" is the surrounding lexical environment associated with the let, which would be computed partly from a parent lexical environment and {a 20 b 10}. The environment and the map could be of the same type and be easy to combine.
But there is no such consideration, and it is actually a good thing that there is no link between how the code is represented and how it is interpreted (also, there can be different interpretations).Basically, I find Clojure a little bit confused about its use of external data representation for code.
I would have preferred a simpler syntax for code and keeping those notations for data, where they are self-describing without additional context. |