#69

Merge with a Function

 

Write a function which takes a function f and a variable number of maps. Your function should return a map that consists of the rest of the maps conj-ed onto the first. If a key occurs in more than one map, the mapping(s) from the latter (left-to-right) should be combined with the mapping in the result by calling (f val-in-result val-in-latter)

	(= (__ * {:a 2, :b 3, :c 4} {:a 2} {:b 2} {:c 5}) {:a 4, :b 6, :c 20})
	(= (__ - {1 10, 2 20} {1 3, 2 10, 3 15}) {1 7, 2 10, 3 15})
	(= (__ concat {:a [3], :b [6]} {:a [4 5], :c [8 9]} {:b [7]}) {:a [3 4 5], :b [6 7], :c [8 9]})