  The expressiveness of communication primitives has been explored in a common
framework based on the pi-calculus by considering four features: synchronism
(asynchronous vs synchronous), arity (monadic vs polyadic data), communication
medium (shared dataspaces vs channel-based), and pattern-matching (binding to a
name vs testing name equality). Here pattern-matching is generalised to account
for terms with internal structure such as in recent calculi like Spi calculi,
Concurrent Pattern Calculus and Psi calculi. This paper explores intensionality
upon terms, in particular communication primitives that can match upon both
names and structures. By means of possibility/impossibility of encodings, this
paper shows that intensionality alone can encode synchronism, arity,
communication-medium, and pattern-matching, yet no combination of these without
intensionality can encode any intensional language.
