On 27/01/2013 14:42, Alexander Klenin wrote:
On Mon, Jan 28, 2013 at 1:26 AM, Paul Ishenin <paul.ishe...@gmail.com> wrote:
27.01.13, 1:43, Sven Barth 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".
I think it is big overkill to implement a new base type for such a small
task as returning a key in for-in loop.
Of course. But note that in this thread, many more uses of tuples
(which I do NOT want to make a type -- see my previous mail for
lengthy explanation why).
Some of the uses are: record and array constructors, adaptation of
inconvenient signatures,
better support for "return code" style of error handling, etc.
If I understand this correct, the ability to return more than one value
from a function (without out parm) is identical to using a record.
Except you do not want a type declaration for a record.
Therefore in this case tuple becomes an "inline" (lack of better word)
declared record (match like you can declare an array outside a "type"
section)
And since it has no named type, it is (other tan records) assignment
compatible if it has the same declaration (same as 2 "array of integer",
only array can not hold different types)
So really here you would need an assignment compatible record (I do not
say it is a good thing, but if the multi return case is addressed, it
may be a better way than toupe)
type
TFoo1 = compatible record a: integer; b: string end;
TFoo2 = compatible record a: integer; b: string end;
function Bar: compatible record a: integer; b: string end;
and variables/results of any of these are assignment compatible.
("compatible record" can be restricted to none variant records)
And (for Michael) I don't see any beauty in this. Imo, initial index
extension is much more beauty than suggested here (a,b,c) := d;
constructions.
I have a compromise suggestion:
Implement for-index extension with the syntax:
for (k, v) in a do
can be solved with records too?
The typeof(a) needs to declare the key values anyway (provide an
iterator, or something)
So together with that, a named record (normal record as exists today)
can be defined? Or am I missing something?
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