Constructor from a multi-constructor type can't be conveniently passed as parameter

[KristianBalaj]

What is your idea? Provide a use case.

Having the following code is not possible:

type Foo {
   BarA {...}
   BarB {...}
}

fn smth(barA: BarA) {
   ...
}

There should be some way how to pass the data as a single parameter so it can be conveniently used in a function.

Why is it a good idea?

A single constructor types can be easily passed as parameters and then used for e.g. record updates using the .. operator. Record updates have to list all the fields one by one becoming too error prone.
Also such datum can be used using a dot access without any unnecessary verbosity.

What is the current alternative and why is it not good enough?

1. All the fields of a constructor can be passed one by one which is verbose and can be used for convenient record updates.
2. A Data can be passed and then used with expect to match the constructor again - it's a little more convenient as 1. but still convenient record updates are not possible.
3. Creating a nested type that can be passed around. This is the most convenient method but changes the format of a type (i.e. adds another constructor which can be unacceptable when a backward compatibility is necessary)

So there's no cool way of achieving this AFAIK.

E.g. PureScript has a nice solution to this, it can pass the parameters as an object {..} aliased with some type and a spread operator can be used for record updates.

[rvcas]

Please start using discussions for this kind of thing. But definitely a cool idea.