More out of curiousity that anything else (but with the expectation that it might occasionally be a useful trick for performance tuning), is it possible to use Clojure macros to "inline" an existing function?
i.e. I would like to be able to do something like:
(defn my-function [a b] (+ a b))
(defn add-3-numbers [a b c]
(inline (my-function
a
(inline (my-function
b
c)))))
And have it produce (at compile time) exactly the same function as if I had inlined the additions myself, such as:
(defn add-3-numbers [a b c]
(+ a (+ b c)))
In case you didn't know, you can define inlined functions using definline
(doc definline)
-------------------------
clojure.core/definline
([name & decl])
Macro
Experimental - like defmacro, except defines a named function whose
body is the expansion, calls to which may be expanded inline as if
it were a macro. Cannot be used with variadic (&) args.
nil
Also checking the source,
(source definline)
-------------------------
(defmacro definline
[name & decl]
(let [[pre-args [args expr]] (split-with (comp not vector?) decl)]
`(do
(defn ~name ~@pre-args ~args ~(apply (eval (list `fn args expr)) args))
(alter-meta! (var ~name) assoc :inline (fn ~name ~args ~expr))
(var ~name))))
definline simply defines a var with meta-data {:inline (fn definition)}. So although its not exactly what you were asking but you can rebind the var with new metadata to get inlined behavior.