[ nice-Feature Requests-1124210 ] let (x,y) = ...

Feature Requests item #1124210, was opened at 2005-02-16 20:16
Message generated for change (Comment added) made by bonniot
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=362788&aid=1124210&group_id=12788

Category: None
Group: None
Status: Open
Priority: 5
Submitted By: Peter Wilson (peterwilson)
Assigned to: Nobody/Anonymous (nobody)
>Summary: let (x,y) = ...

Initial Comment:
Make access to tupple contents easier. I believe Groovy
has this feature:

Taken from manual.html:Example 7.2. Method returning
several values using a tuple

#1 usage improvement: allow local variables on tupple
returns:

declaration:
(int, int) minMax(int x, int y) = x < y ? (x, y) : (y, x);
use:
(x, y) = minMax(3,5); // not very convincing for this
function.
  println("(" + x + ", " + y + ")");

#2 usage improvement: allow local variables on tupple
arguments:
void printTuple((int x, int y) tuple)
{
//  /** Declare two local variables, and assign to each
the //corresponding value
//      in the tuple.
//  */
//  (int x, int y) = tuple;

  println("(" + x + ", " + y + ")");
}

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>Comment By: Daniel Bonniot (bonniot)
Date: 2005-02-23 15:39

Message:
Logged In: YES 
user_id=88952

OK, I updated the manual accordingly.

I leave this report open, as I believe it would be useful to
support the 'let (x,y) = ...' syntax.

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Comment By: Nobody/Anonymous (nobody)
Date: 2005-02-22 21:11

Message:
Logged In: NO 

My misunderstanding. - From your reply, the  current usage
is fine. 

However, example 7.2 in the User's Manual is misleading as
it fails to use  feature #2. It should be updated, or shown
as an alternative.


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Comment By: Daniel Bonniot (bonniot)
Date: 2005-02-22 18:15

Message:
Logged In: YES 
user_id=88952

I'd like to ask for some clarifications:

For #1:
You can already do
  (x, y) = minMax(3,5);
provided that x and y are previously declared. You can also
declared them at that spot with:
  (int x, int y) = minMax(3,5);

Is that you want to be able to declare them without
specifying the type? I believe this could be useful, but a
specific syntax should be used to make that clear.
Consistently, this should be
  let (x, y) = minMax(3,5);
and
  var (x, y) = minMax(3,5);
for constant and variables, respectively.

Does this correspond to what you expected?

For #2:
Unless I'm mistaken, what you are asking for is already
possible:
  void printTuple((int x, int y) tuple)

You can even leave the name 'tuple' out since it is not used:
  void printTuple((int x, int y))

Is that so? Is this missing from the documentation?


----------------------------------------------------------------------

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