chickadee » integer-map » fxmapping-union/combinator

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 v₁, v₂, …, vₙ in fxmap₁, fxmap₂, …, fxmapₙ, respectively, then the resulting fxmapping will contain the association (k, (proc k … (proc k v₁ v₂) … vₙ)).

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"))