Discussion Thread: DIP 1030--Named Arguments--Final Review

[Oraby]

On Wednesday, 13 May 2020 at 00:37:51 UTC, Walter Bright wrote:
> We already have named arguments in D since the very beginning - 
> the struct initialization syntax.
>
> Not a single person has complained about breakage when 
> implementers changed the names of the struct fields.
>
> This is similar to:
>
> 1. what happens if the implementer changes the types of the 
> parameters?
>
> 2. what happens if the implementer changes the order of the 
> parameters?
>
> Then user code breaks.
>
> If anything, this feature will motivate implementers to take 
> some care to name the parameters appropriately.


How about providing a migration path by adding the ability to 
deprecate named arguments. In such way, libraries can warn users 
that a parameter is now deprecated either in favor of 
otherparameters or for future removal.

An alternative but similar approach would be to enable functions 
to introspect whether a named argument was called as named or 
not, in such way the user can provide more verbose deprecation 
messages without polluting function signature.