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I think the convention predates both. boost::bind for C++ does something similar: http://www.boost.org/doc/libs/1_40_0/libs/bind/bind.html

I think Clojure copied Arc on this.

Actually it was inspired by Mathematica:

Goo appears to have something similar in its op (partial evaluation) function.

At least the _ part is used in both Haskell and Prolog.