Discussion Thread: DIP 1037--Add Unary Operator ...--Community Review Round 1

[Ola Fosheim Grøstad]

On Wednesday, 28 October 2020 at 14:48:48 UTC, Manu wrote:
> Definitely not my DIP. I can immediately imagine heaps of 
> issues with that
> idea, and I have never wanted that before.
> If you want to do a non-static map, then use `map`, which 
> accepts a lambda
> and looks and feels very natural and convenient.

Make the syntax uniform. Don't continue with special cases...

> Not sure what this means? You can slice tuples in D, does that 
> not give you the ability to offset as you like?

That was an example. Reverse. Every other etc.

> I don't think this is necessary, and it is deliberately omitted.

That is a serious omission. Fold needs an initial value in order 
to be generic.

>> IN:
>> (seq1[_]*10 + seq2[_+1], ...)
>>
>> OUT (e.g. length = min(seq1.length, seq2.length):
>> (seq1[0]*10 + seq2[1], seq1[1]*10 + seq2[2], seq1[2]*10 + 
>> seq2[3])
>
>
> That looks like a minefield of grammatical issues.

No, it isn't. D uses a recursive descent parser and it will 
evaluate the first expression to an expression with a special 
token. Trivial extension of the parser.

> Why would you prefer that with the comma separating the 
> expression and `...`?

Because what you proposed is not intuitive:

"(seq1)..."

does not give any hint of it being expanded to a comma separated 
list. That is not good from a usability point of view 
(legibility).