On Jul 29, 2:02 pm, Ken Wesson <[email protected]> wrote:
> (fn [& args]
> (let [argmap__5673__auto (#'some-ns/parse-args args)
> foo (or (:foo argmap__5673__auto) 42)
> bar (or (:bar argmap__5673__auto) nil)
> ...]
> (body goes here)))
> where you define a private parse-args function in your namespace to
> turn an argument seq into a map of argument name keywords to values,
> with some omissions, and 42 and nil are the defaults which the macro
> builds right into the function.
>
> Of course, this has the slight issue that arguments whose values are
> false or nil will be changed to their defaults. You may need some
> trickier handling, e.g.
>
> (let [...
> foo (:foo argmap__5673__auto)
> foo (if (:foo argmap__5673__auto) foo 42)
> ...]
> ...)
(get :foo argmap__5673__auto 42) is the right way to solve this
problem.
Or if, as in the current example, you want to destructure a map with
lots of defaults, simply:
(let [{:keys [foo bar] :or {foo 42}} (parse-whatever)]
...body...)
>
> or
>
> (let [...
> foo (find argmap__5673__auto :foo)
> foo (if foo (val foo) 42)
> ...]
> ...)
>
> --
> Protege: What is this seething mass of parentheses?!
> Master: Your father's Lisp REPL. This is the language of a true
> hacker. Not as clumsy or random as C++; a language for a more
> civilized age.
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