Re: [RFC] Syntax for appending elements to arrays

[Jose E. Marchesi]

> At the moment we support concatenating arrays by creating new array
> values:
>
>   [1,2,3] + [4,5,6] -> evaluates to a new array value [1,2,3,4,5,6]
>
> However, in poke we can have really BIG arrays, and the above can become
> problematic in terms of memory consumption and also performance.
>
> So I suggest adding syntax to append new elements to existing array
> values.  I see two options here:
>
> 1) To do it in an expression, like:
>
>    [1,2,3] + 4 -> appends 4 to the given array and then evaluates to
>                   the modified array.
>
>    This would of course imply the availability of the corresponding
>    statement:
>
>    var a = [1,2,3];
>    a += 4;
>
>
> 2) To only allow the statement form:
>
>    var a = [1,2,3];
>    a += 4;
>
> I think I am inclined for 2) more than for 1), because it makes the
> side-effect more explicit.
>
> A disadvantage of 2) is that not allowing `[1,2,3] + 4' may be
> unexpected for the programmer.
>
> Opinions?

I just realized 2) is unfortunately ambiguous with the existing
array-concatenation operation.  If you have:

  var a = [[1,2],[3,4]];

And you do:

  a += [5,6];

Are you actually trying to concatenate the arrays [[1,2],[3,4]] and
[5,6], in which case you want a syntax error, or

Are you actually tring to append an element [5,6]?

If no one comes with some sane syntax for this, we will have to resort
to the usual notation:

  a.push ([5,6]) or,
  a.append ([5,6])

But I would really want to avoid that if possible..

No more ideas, anyone?