Pretty please: Named arguments

[bearophile]

Adam Ruppe:

> Size size;
> size.width = 10;
> size.height = 20;
> 
> Instead of Size(10, 20).

This adds more clutter compared to argument names and requires more lines...


> Another alternative is to give each element their own struct...
> 
> struct Width { int width; alias width this; }
> 
> foo(Width(10), Height(20));

Time ago in D there was typedef for this. There are many problems with this solution:
- You can't use this to give the arguments in a different order, or specify only part of the default arguments.
- this can't be used with functions written by other people that don't already use structs for arguments
- This forces you to always use those names at the calling point, while named arguments are usually optional at the calling point.
- you need to define a new struct for each argument you may want to call with a name, this requires code and increases binary size for nothing.
- Maybe there are problems with padding, like if the wrapped argument is an array ubyte[5].
- I think currently alias this is not fully transparent

Bye,
bearophile