We haven't seen the use-case yet where the (signature,payload) tuple is not isomorphic to a transaction. Yes, in the case of multiple, distinct payloads, you'd have to break those into separate transactions, but that seems like a very specific use-case that doesn't sound very "transactional".

Pact's philosophy sees a blockchain as a special-purpose database, for distributed transactions, so it's not designed for many "normal" database cases, namely bulk operations, searches, heuristics, etc. The use case of accepting multiple signed payloads sounds suspiciously "batchy" to me. Also, Pact is "success-oriented": we see failures like a bad signature as something that should fail your tx only. This is a way of avoiding dicey control-flow logic.

So, if a single payload is what you need the signatures on, you simply design your contract API/function call to have the specific function to handle that data (store it in the database, whatever), and let the environment check the signature.

EDIT: Pact is actually `([Signature],payload)` -- ie, you can sign the same payload multiple times

Signing the same payload multiple times would work for my use case (channels). I also need to accept transactions signed by at least one of two keys. I suspect this might be possible too. However, I can imagine that anything more complicated would go outside of the system you have designed. I haven't had the chance to learn your language, but I would be wary about it either being too limited for edge cases that most real world stuff is going to have, or turning into a "universal framework" antipattern.

> I also need to accept transactions signed by at least one of two keys.

Keysets are designed for precisely this; what's more this rule can now be persisted.

> anything more complicated would go outside of the system you have designed.

Always a possibility of any PL, especially running in a blockchain. Pact makes less assumptions about use cases than most however. It's imperative, allows functions and modules, and offers a database metaphor. That handles a fair number of things.