[owl57]

I believe that if most foo's users should just call it with [], the Pythonic way is to make the argument optional.

[samatman]

Well yes, but if it's someone else's library, realistically you're not going to change it.

Zig is a static language without variadic parameters, so you can't make it optional in that sense. You could make the options a `?T` and pass `null` instead, but it isn't idiomatic, because passing `.{}` to a parameter expecting a `T` will fill in all the default values for you.

[xigoi]

This doesn’t answer the question why Zig doesn’t have default argument values.