On Thu, Jul 22, 2021, at 12:54, Simon Peyton Jones wrote:
Thanks Eric
| adding syntax for multi-arg case is concerns around back compat. If we could | go back in time and revise the original \case syntax to support multiple | arguments, would we still end up with a single-arg construct and a multi-arg | construct? I think probably not.
Actually I don't agree. I think we might well have \case (for 1) and \cases (for 0-n) because * the cognitive overhead is vanishingly small (especially given the singular/plural form * the absence of parens in the very common case of \case is extremely convenient
I actively like the signal that \cases gives me, up front, "here comes an nary lambda", rather than the very quiet commas of (2). Whereas I know that \case is always unary.
We don't have separate unary / n-ary constructs for function definitions or lambdas. Do you think we should make the distinction there too? I don't understand what makes \case so different. The paren issue is valid, but in my opinion option (2) solves it better with the comma separators.