Named constructors

[H. S. Teoh]

On Wed, Jan 09, 2019 at 05:30:32PM +0000, Atila Neves via Digitalmars-d wrote:
> On Wednesday, 9 January 2019 at 07:47:02 UTC, Dru wrote:
> > Another way to distinguish between constructors is needed.  Because
> > it is possible to have two different constructors that take the same
> > arguments.  Adding dummy arguments that are unused hurts code
> > clarity.
> 
> Adding dummy arguments is unecessary. Just use the type system:
> 
> struct Person {
>     this(FirstName firstName, LastName lastName) { /* ... */ }
> }
> 
> struct FirstName { string value; }
> struct LastName  { string value; }

+1. That's what the type system is for.  Dummy arguments are NEVER a
good idea unless there's a need for the API to be uniform.

It also makes the calling code self-documenting without needing language
support for named arguments:

	auto myPerson = Person(FirstName("John"), LastName("Doe"));

rather than the opaque (and thus error-prone):

	// Bug 1234: hmm, is it first name first, or last name first?
	//auto myPerson = Person("Doe", "John");
	auto myPerson = Person("John", "Doe");


T

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