Unions and intersections in gradual typing Sample Clauses

Unions and intersections in gradual typing. ▇▇▇▇▇▇▇▇ et. al [10] introduce a gradual type system based on so-called set-theoretic types [12]. Set-theoretic types fea- ture unions, intersections, negation types together with a notion of subtyping. This work adheres to the static first school (see [13]) of gradual typing: the reason for gradual types is to allow for a less precise type information. It fol- lows that their goals and constraints are somehow differ- ent, resulting in the absence of first-class contracts. As for any gradual type system, they do have to implement casts – that are very close to contracts – for unions and intersec- tions, but these casts are neither visible nor available to the programmer. Obviously, no contracts mean no user-defined contracts as well.