问题
Even looking closely over documentation on Clojure, I do not see any direct confirmation as to whether or not Clojure supports operator overloading.
If it does, could someone provide me with a quick snipplet of how to overload, let's say, the "+" operator to delegate to some predefined method that we can call myPlus.
I am very new to Clojure, so someone's help here would be greatly appreciated.
回答1:
Clojure's (as any Lisp's) operators are plain functions; you can define an "operator" like a function:
(defn ** [x y] (Math/pow x y))
The "+" operator (and some other math-operators) is a special case in Clojure, since it is inlined (for the binary case, at least). You can to a certain extent avoid this by not referring to clojure.core (or excluding clojure.core/+) in your namespace, but this can be very hairy.
To create a namespace where + is redefined:
(ns my-ns
(:refer-clojure :exclude [+]))
(defn + [x y] (println x y))
(+ "look" "ma")
One good strategy would probably be to make your + a multimethod and call core's + function for the numeric cases.
回答2:
Take a look at this: http://clojure.org/multimethods
Certain functions, like + are core and cannot be redefined.
You could make a new function and call it ".+" or "!+" for example, which is similar in terms of readability.
Using the information in the multimethods URL included above, you can build a function that tells your .+ which implementation to use.
来源：https://stackoverflow.com/questions/1535176/operator-overloading-in-clojure