module Targetmap: sig .. end
target keyed finite maps
include Finite_map.Fmap
val apply_target : 'a t -> Target.target -> 'a option
apply_target m targ looks up the targ in map m.
Target-maps only store information for real targets, not the identity one.
If therefore targ is Target_ident, i.e. represents the identity backend,
None is returned.
val insert_target : 'a t -> Target.target * 'a -> 'a t
insert_target m (targ, v) inserts value v for targ in map m.
Target-maps only store information for real targets, not the identity one.
If therefore targ is Target_ident, i.e. represents the identity backend,
the map is not(!) updated.