compare:用于生成cmp函数的ReasonML助手

比较 用于生成cmp函数的ReasonML帮助器。 用法 module Comparator = Belt . Id . MakeComparable ({ type t = string ; let cmp = Compare . concat( [ Compare . by(key => key) , Compare . by(key => String . length(key)) , ] ) ; }) ; type t = Belt . Map . t ( Comparator . t , int , Comparator . identity ) ; let ourMap = Belt . Map . fromArray(~id = ( module Comparator ) , [| ( "a"