If You See What I Mean.Landin 1966.ISWIM is {purely functional}, a sugaring of {lambda-calculus}, and the ancestor of most modern applicative languages.An ISWIM program is a single expression qualified by ' where'clauses (auxiliary definitions including equations among variables), conditional expressions and function definitions.ISWIM was the first language to use lazy evaluation and introduced the {offside rule} for indentation.["The Next 700 Programming Languages", P.J. Landin, CACM 9(3):157-166 (Mar 1966)].