Passing function parameters by name

[Janice Caron]

On Dec 5, 2007 1:48 PM, renoX <renosky at free.fr> wrote:
> I could ask the opposite question: why should we restrict the API to the function and object name instead of using the full data that we have?

Another thought. If the name were part of the API then could one
overload functions by parameter name? e.g.

    void f(int a) { /* do something */ }
    void f(int b) { /* do something different */ }

After all, if the name were part of the API, then they have different APIs.

I'm not convinced that this is a good idea. It's also not the only
alternative. I have in the past written programs which take parameters
of the same underlying type in any order, using only D-as-it-is-now
(or C++), and it's not so hard. For example, suppose you want a
function that looks like

    MyDate makeDate(int month, int day, int year)

but you think callers might get confused about what order to pass the
parameters in (European date order, American date order, YMD date
order, whatever...)

    typedef int Year;
    typedef int Month;
    typedef int Day;

    MyDate makeDate(Year y; Month m, Day d) {/*...*/ }
    MyDate makeDate(Year y, Day d, Month m) { return MyDate(y,m,d); }
    MyDate makeDate(Day d, Month m, Year y) { return MyDate(y,m,d); }
    MyDate makeDate(Month m, Day d, Year y) { return MyDate(y,m,d); }

That forces callers to name their arguments, as in:

    MyDate date = makeDate(cast(Day)11, cast(Month)11, cast(Year)1999);

If you wanted, you could also add a "default" function that took ints
but required parameters in the right order.

And that, basically, is problem solved, as far as I can see.