`fxmapping-union/combinator``proc``fxmap₁``fxmap₂``fxmap₃``…`procedure`fxmapping-intersection/combinator``proc``fxmap₁``fxmap₂``fxmap₃``…`procedure*proc*is a procedure of type`fixnum * * → *`.Return a fxmapping whose set of keys is the union/intersection of the sets of keys of the

*fxmaps*. The values associated with duplicate keys are combined left-associatively with*proc*, which is also passed the duplicated key as its first argument; that is, if an integer*k*is associated with values*v*₁,*v*₂, …,*v*ₙ in*fxmap*₁,*fxmap*₂, …,*fxmap*ₙ, respectively, then the resulting fxmapping will contain the association (*k*, (*proc k*… (*proc k v*₁*v*₂) …*v*ₙ)).Examples:

;; Right-biased union. (fxmapping->alist (fxmapping-union/combinator (lambda (_k _l r) r) (fxmapping 1 'b 2 'c) (fxmapping 2 "data" 3 "picard"))) ⇒ ((1 . b) (2 . "data") (3 . "picard")) (fxmapping->alist (fxmapping-intersection/combinator (lambda (_ l r) (string-append l " " r)) (fxmapping 1 "q" 3 "jean-luc" 5 "miles" 7 "quark") (fxmapping 3 "picard" 5 "o'brien"))) ⇒ ((3 . "jean-luc picard") (5 . "miles o'brien"))