> To start with a practical example, ...
Syntactic issues aside, you start with an example that cannot be checked for
exhaustiveness and so is pretty much against the idea of `case`.
The reason why pattern matching needs to be built into the language is not
convenience (you can get that with a PM macro easily enough even though nobody
uses that for macros right now) but safety. Right now Nim's case objects are
not safe:
type
E = enum
valA, valB
Obj = object
case k: E
of valA: a: int
of valB: b: string
proc modify(o: var Obj) =
reset(o)
o.k = valB
o.b = "xx"
case x.kind
of valA:
modify(x)
echo x.a
of valB: ...
