Feature request: optional arguments/struct fields etc

[steffahn]

See also:

Possibly one small step towards named arguments

There definitely is interest. You assume correctly. There's 700+ comments to read there, probably more. As for why things haven't been implemented - there's no consensus on how, or even if they should be implemented. That's why I think macro explorations of this are useful. I like this summary best of how hairy of a topic this is:

(this is talking about named arguments, but many of the links talk about default arguments, i.e. optional arguments, as well)