Hi all,
I have some functions that use destructuring on a map parameter, and it
seems I have a false assumption on the workings. Take for example this
one:
(defn foo
[{:keys [a b]
:or {a 1 b 2}
:as all}]
[(hash-map :a a :b b) all])
I expected it to always return a vector of two equal maps. However,
that's not true. all is in fact the map I gave at the call, not the map
with the default values declared in the :or applied.
Why is that? So that you can distinguish given actual args that happen
to match default values from real, non-given defaults?
That somehow makes sense, but is there some way to get the complete map
with defaults applied, too?
In my application, I don't care about if some value is an implicit or
explicit default, but I have some functions with many keys that are
split in two subfunctions. One public frontend functions with :or in
order to let callers see the defaults, and one private function that
does the actual work, assumes correct args and is called by the public
one:
(defn- foo-1 [{:keys [a b c]}] ...)
(def foo [{:keys [a b c]
:or {a 1 b 2 c 3}
:as all}]
;; do some stuff
;; (foo-1 all) ;; That won't work, instead I have to do the lengthy...
(foo-1 (hash-map :a a :b b :c c))
;; do more stuff
)
Any recourse?
Bye,
Tassilo
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