Why isn't the form Class? valid when the no args constructor can error, while with args form is valid? Could it be a bug or rough edge that hasn't been considered yet?
class A
new create(x : I32) ? =>
if (x % 2) == 0 then
error
end
class B
new create() ? =>
error
actor Main
new create(env: Env) =>
try
let x = A(1)? // legal
let y = B.create()? // why not `B?`? `B()?` seems to expand to `create().apply()?`
else
env.out.print("exception")
end
This appears to be a syntactic limitation in current Pony. For a total zero-argument constructor call, you would use the type name without parentheses, like this:
let y = B
For a partial call, you would expect you can use this (still without parentheses):
let y = B?
But this is currently not syntactically valid. It seems like a logical extension (assuming that it does not conflict with anything else syntactically).