On Thursday, September 27, 2012 11:37:10 foobar wrote: > I do _not_ want to consider two different _structs_ (nominal > types) as the same type. I would like to get correct tuple > semantics which means _structural_ typing (I thought I emphasized > that enough in the OP). > A tuple is defined by its contained types, *not* its name.
What on earth does structural typing get you here? A tuple is a collection of values of varying types. If you have Tuple!(X, Y, Z), it defines a tuple containing the types X, Y, and Z. _All_ tuples with those types will be Tuple! (X, Y, Z). The _only_ reason that this isn't quite the case is the nonsense with being able to give names to the fields in a tuple (and adding an alias this to Tuple should be able to fix that). Being able to create your own tuple type which you can compare with Tuple simply because it happens to hold the same types is completely pointless as far as I can tell (but you can still do it if you really want to). If you want a tuple, then just use std.typecons.Tuple. Creating another tuple type buys you nothing. - Jonathan M Davis
