Re: RFC - Array slice syntactic sugar

On 19/03/2015 20:49, Alex Bowers wrote:

My proposal is something similar to Pythons slice, in PHP this would look like: $slided = $array[1:4] This will get the elements in positions 1,2,3,4. (1 through 4 inclusive), ignoring the actual key of the array. The result for an array will be an array with the keys preserved, in the same order.

While I can see the reasoning for not looking into the actual keys (which might not have a logically sliceable order), I think the syntax needs to be more distinct, because this seems a bit confusing: $countdown = [ 5 => 'Five!', 4 => 'Four!', 3 => 'Three!', 2 => 'Two!', 1 => 'One!', 0 => 'Zero!' ] $countdown[0]; // 'Zero!' $countdown[0:0]; // ['Five!'] $countdown[0:][0] // 'Zero!' $countdown[:0][0] // null - slice contains no key 0 The problem is that the slice access looks like an extension of key access, but is actually a new concept of positional element access. With a slight tweak to syntax, such as adding an @, we could make positional access available for non-slices as well: reset($countdown); // Five! - a common way of getting the first element positionally $countdown[@0]; // 'Five!' $countdown[@1]; // 'Four!' $countdown[@0:0] // ['Five!'] $countdown[@0:1] // ['Five!', 'Four!'] $countdown[@0:][@0] // 'Five!' $countdown[@:0][@0] // 'Five!'

A side addition, that may be considered is adding [-1] to get the last item in the array. But that is not a main part of this RFC.

This would actually be a really important addition for me, but only if I can do it on a non-slice, as above: $countdown[-1]; // null - no such key end($countdown); // 'Zero!' - common way of getting last element $countdown[@-1]; // 'Zero!' - positional access counting from the end $countdown[@-2]; // 'One!' - fiddly to do in current PHP I just wrote out all those examples and realised that it may not be possible to reuse @ in this context. Finding new symbols to use for syntax is hard. :( Regards, -- Rowan Collins [IMSoP]