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frenchy64/update-in-macro.clj

Last active August 29, 2015 14:12
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update-in-macro.clj
(defmacro update-in*
"'Updates' a value in a nested associative structure, where ks is a
sequence of keys and f is a function that will take the old value
and any supplied args and return the new value, and returns a new
nested structure. If any levels do not exist, hash-maps will be
created."
([m [k & ks] f & args]
(if ks
`(let [m# ~m k# ~k] (assoc m# k# (update-in* (get m# k#) ~ks ~f ~@args)))
`(let [m# ~m k# ~k] (assoc m# k# (~f (get m# k#) ~@args))))))
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