Tuples

[Manu]

I have certainly been confused by the term 'tuple' used in D countless
times.
It seems to exist in a variety of different contexts, and every time I
think I understood it, I realise I'm probably wrong some time later.
There seems to be poor/no documentation comparing/distinguishing various D
tuples, also, there seems to be no real explicit syntax, which makes it
hard to recognise.
I can kinda handle a Tuple template, and then there are these type tuples,
and then expression tuples? What is the relationship between these? Are
they compatible? How do I distinguish them?

Someone that understand what they're talking about should take some time to
write a comprehensive article on the matter :)
Some of the things I have read seem to presume that I already know what
it's talking about, and as a result, lead to dismissing or misunderstanding
the article.

I think the practical take-away from my experience is that it ends up as
one of those 'too hard' concepts, that I develop a tendency to actively
avoid dealing with because it's confused me a number of times.
I typically just start typing stuff and hope it works. And if it doesn't I
fiddle with it until it eventually does (or I give up), and I never
*really* understand why.
I'll bet I'm not the only one...


On 27 May 2013 10:25, Jonathan M Davis <jmdavisProg at gmx.com> wrote:

> On Sunday, May 26, 2013 22:38:24 Diggory wrote:
> > On Sunday, 26 May 2013 at 15:48:00 UTC, Russel Winder wrote:
> > > I wonder if people coming to D, looking for information about
> > > tuples,
> > > will get confused by http://dlang.org/tuple.html which seems to
> > > tell
> > > people they have to "roll their own", and
> > > http://dlang.org/phobos/std_typecons.html which tells people
> > > they have
> > > been pre-rolled in the standard library?
> >
> > I found this especially confusing because the built-in Tuple is
> > defined differently.
> >
> > The Tuple in that example is equivalent to the definition of
> > TypeTuple, and yet TypeTuple is supposedly specific to types
> > while that example (as so by implication TypeTuple) apparently
> > works just as well with other contents.
> >
> > On top of that Tuple is the one that only works with types - any
> > string expressions are extracted and used as names... Surely a
> > tuple which can only store types should be a TypeTyple and a
> > tuple which can store anything should be a Tuple.
>
> I really wish that the term tuple didn't get used with the built-in tuples
> /
> TypeTuples. They _aren't_ tuples. They're similar, but they don't nest, and
> they cause a lot of confusion with std.typecons.Tuple. And they're only
> compile-time constructs to boot.
>
> - Jonathan M Davis
>
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