cjfrisz / core.match Goto Github PK

Currently, core.match allows for matching on one or more items thanks to Lisp-style sequence destructuring. For example, consider the following match clause:

[([a & b] :seq)] rhs

This will match a sequence of one or more items, with the first bound to a and the rest bound to a sequence identified by b.

This is pretty nice, but it falls short of the niceness we get in IU Scheme Match. Specifically, consider the following match clause in IU Scheme:

[(a* ...) rhs]

This will return a list matching all the elements if matching on a list (though this is pretty silly in practice). Note that this will match on the empty list, but there's no way express the same thing in clojure.core.match.

I'd be interested to see if this is possible, even if added with a more Scheme-like syntax.

Again, Clojure's core.match, while quite nice, lacks some of the trimmings of IU Scheme Match. Of note is the catamorphism syntax, or at least the simple version. In IU Match, this allows for recurring to the same instance of match with the variable(s) that matched the given pattern.

The official core.match repo claims that predicate dispatch is on their road map. This might map onto catamorphism syntax, so I'll have to stay apprised of that.