Named constructors

[Neia Neutuladh]

On Thu, 10 Jan 2019 13:53:40 +0000, Atila Neves wrote:
> What's the _real_ difference between `someFunc(firstName="Alice")` and
> `someFunc(FirstName("Alice"))`?
> The former saves one character?

It means you don't need to declare a new struct for every function 
parameter.

Even if you are willing to declare a new struct for every function 
parameter, it means you don't have to do the work of either creating a 
unique name for each one (which would be annoying to users) or manually 
garbage collecting the structs as your code evolves (in case a parameter 
struct is used by multiple functions).

Even if you're willing to do the work of declaring a new struct for each 
paramater, using short names, and manually garbage collecting them, 
language-provided named parameters mean that your end users don't need to 
worry about name collisions between two modules using struct wrappers as 
named parameters.

Even if you're willing to do the work of declaring a new struct for each 
parameter, with short names and manually maintaining a minimal set of 
parameter structs, and you're willing to make your code's consumers deal 
with naming conflicts, you still don't get reorderable parameters. For 
that, you need to turn a function into a wrapper template that accepts 
parameters in any order and forwards them to an implementation function in 
a fixed order. This makes it difficult to take the address of the function.

So, no, just using wrapper structs is not a serious alternative.