CakeML
Support pattern matching in let declarations
Currently the grammar only supports a limited subset of declarations within let expressions (the LetDec non-terminal). It would be nice if these could be expanded to allow pattern-matching and wildcards.
(Supporting everything in Decl would be great, but presumably local type declarations are the problem. This issue can be closed without supporting them.)
The grammar and parsing for this change would be easy. The more significant change would be giving this syntax a target in the AST type and then ensuring that those ASTs were properly compiled. (For example, when you have val inside a let it can only be a variable name because that's what the ast$Let constructor allows . This contrasts with the fact that val as part of a top-level declaration takes a pattern.)
Right, this is mostly an AST enhancement/complication. @SOwens might like to weigh in.