Re: [pure-lang-users] Proposed syntax changes

[Libor S. <li...@gm...>]

On Fri, 15 Aug 2008 02:16:40 +0100, Albert Graef <Dr....@t-...> wrote:

> Libor Spacek wrote:
>> I am not entirely convinced that the tuples are even worth having at all.
>> For the minimal (flatness) distinction, they ship in a lot of confusion.
>
> Can you elaborate on that? The only complication I see is the borked
> list-of-tuples syntax, and I'm about to fix that (hopefully!).
>

Both lists and tuples are devices for ordering and grouping some items.

I do not see the problem with using a pair of brackets to make the grouping explicit, as in the list [1,2,3] instead of relying on the precendence of the associativity and using a tuple 1,2,3. I have learnt through painful experience not to rely on remembering the exact precedence
of numerous associative operators, especially when I can add my own.

Maybe it is just me but when using Pure, I am always worrying: 'is this a tuple or is it a list?' I need to worry about it because selectors and functions will typically work only on one but not on the other. To give a trivial example:

head (1..3); // is OK
head (1,2,3); // is not OK

So, if I return 1,2,3 instead of [1,2,3], everything falls down round my ears.
I guess you will say that I ought to know better and you will be right.

To complicate things further, I can also in many situations use simply 1 2 3, e.g.
>let a = 1 2 3;
>a;
1 2 3

So there are three ways of ordering and grouping items which are nearly the same but not quite,
which I, at least, find  a little bewildering.

L.