[fpc-devel] RFC: Support for new type "tuple" v0.1

[Michael Van Canneyt]

On Sun, 27 Jan 2013, Alexander Klenin wrote:

> On Sun, Jan 27, 2013 at 4:43 AM, Sven Barth <pascaldragon at googlemail.com> wrote:
>> Based on the results of the "for-in-index" thread I've decided to come up
>> with a draft for the Tuple type which is thought by many people to be a
>> better alternative to "for-in-index".
>>
>> Please note the following points:
>> * This is not the final specification for Tuples and thus open to discussion
>> (there are still some issues with this draft that need to be solved)
>> * I won't implement this feature myself (at least not in the near future) as
>> I have other topics on my list (most importantly generics once type helpers
>> are commited), so Alexander is free to give the task for implementation to
>> his student.
>>
>
> Heh, I have started to write similar in form, but different in
> substance proposal, but needed some sleep,
> and you have beaten me to it :)
>
> I want to quickly summarize the most important points of my proposal
> before writing it out in length:
>
> 1) In a form proposed by Sven (and, IIUC, implemented in Oxygen),
> tuples are not different enough from records
> (so perhaps a term like "anonymous records" is preferable, as well of
> re-using keyword "record").
> I agree that anonymous records might be good, but I consider them a
> separate, and weaker, extension.
>
> 2) The most important differentiating features of my proposal are:
>
> 2.1) Tuples are always temporary and anonymous. You can not store a
> tuple, define tuple type, of variable of tuple type.
>  So tuples are 100% static, compile-time feature -- no change to
> RTTI, variants etc.

No.

I think that tuples should be a full fledged type, not an anonymous 
one with all the restrictions that come from it. Pascal is declarative.
So, you must declare a tuple when you want one.

As for notation:
Adding the () brackets to indicate a tuple adds to clarity, simply 
relying on the comma to indicate a tuple is not acceptable. 
Pascal IS a verbose language. If you want unreadable: go for Javascript.

I consider Sven's proposal the one to go for. 
It is more in line with what Object Pascal stands for.

The idea of a tuple is already a concession to avoid the "for in index" monstrosity.

So let's not get carried away too much.

Michael.