A Calculus of Tagged Types, with applications to process languages

Tagged Types encode some families of types indexed by labels. Like Wand’s row types, they make use of specific variables from which new fields can be extracted, and like Rémy’s record types, the types introduced in these fields can be parameterized. However, the logical and technical treatment of tagged types is original; it is claimed that they combine the intuitiveness of row types with most of the expressiveness of record types. Their use is illustrated by the design of polymorphic typing systems for various process calculi extending CCS. Processes are assigned types which associate polymorphic types with all communication labels.