1signature Varmap = sig 2 type varmap = (string, int) Binarymap.dict 3 exception unifyVarmapError 4 val size : varmap -> int 5 val dest : varmap -> (string * int) list 6 val extends : varmap -> varmap -> bool 7 val insert : string * int -> varmap -> varmap 8 val empty : varmap 9 val eq : varmap * varmap -> bool 10 val peek : varmap -> string -> int option 11 val unify : varmap -> varmap -> varmap 12 val remove : string -> varmap -> varmap 13end 14