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June 29, 2019 02:54
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macro that given a sequence of values and default binding values evaluates body of form with bindings in args or defaults.
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(ns with-args) | |
;; input | |
#_(with-args args | |
[hostname "127.0.0.1" ;; default values if args at position are not provided | |
port "3030"] | |
[hostname port]) | |
;; output | |
#_(let [{hostname 0 | |
port 1 | |
:or {hostname "127.0.0.1" | |
port "3030"}} (vec args)] | |
[hostname port]) | |
;; wors with argv | |
#_( | |
(defmacro with-args | |
"Bind a sequence of values to defaults listed in `arg-bindings` and evaluate body. " | |
{:style/indent [1]} | |
[argv arg-bindings & body] | |
(let [bind-list (->> (partition 2 arg-bindings) | |
(map-indexed (fn [i v] | |
[(first v) i])) | |
flatten) | |
bind-form (-> (apply hash-map bind-list) | |
(assoc :or (apply hash-map arg-bindings)))] | |
`(let [~bind-form (vec ~argv)] | |
~@body))) |
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