Types and Programming Languages

of full type reconstruction for System F, 354

of partial type reconstruction for System F, 354

of subtyping for System F_<:, 427–431

undefinedness vs. failure, 16

unification, 321, 326–329

union types, 142, 206–207

disjoint, 142

uniqueness of normal forms, 39

uniqueness of types, 94, 104, 511

and annotations, 135, 141

and sums, 134–135

Unit type, 118–119

unit value, 118–119

units (in Scheme), 368

universal domain, 273

universal set, 282

universal types, 339–361

unsafe declarations, 7

untyped implementation, 83–88

untyped arithmetic expressions, 23–44

untyped lambda-calculus, 11, 51–73

representation using recursive types, 273–275

up-cast, see casting

update, polymorphic, 482–485