Negative List Indices and other List fun

ID:891912
 
Jul 26 2012, 8:09 pm
Keywords: index, list, python
Applies to:Dream Maker
Status: Open
Issue hasn't been assigned a status value.
It would be amazing if we could use negative indices in lists. Similar to the recent feature of negative values in text functions.

I believe this would allow for cleaner code when working with lists. To get the last element of a list we could do:
world << list[-1]

Instead of:
world << list[list.len]


It would also be great if we could extend this to list features similar to the slices used in Python. For example:

var/list/L = list(1,2,3,4,5,6,7,8)

//If we want the forth element onward we have to do:
L.copy(4,0)

//With new notation we could do:
L[4:0]


An optional third element could also be added as the stride:

L[::2] //Returns every other element
L[2:5:2] //Every other element from 2 to 5
L[::-1] //Reverses a list




#1 Jul 26 2012, 8:17 pm
I support increased list functions.
#2 Jul 28 2012, 4:38 pm
This functionality would be a great addition, matching the text function feature. I'm surprised I didn't request this side-by-side with my feature request.
#3 Jul 30 2012, 1:53 am
DM has chosen to do things via procedures attached to the special /list object; altering that now is a bit of a stretch, and if you were to do that you'd want it to be a replacement of Copy() etc, not an addition.

The only thing not actually possible already through the existing list procedures / for-loop skip, is the list reversing. I wouldn't mind list.Reverse, although its fairly trivial to implement given list.Swap. In fact, Swap was primarily implemented to support user-created sorting routines, such as a reversal.
#4 Aug 4 2012, 8:40 am
It would be awesome if we could override list procs or add new ones, like a sorting function. Right now it's not allowed ;_;
#5 Aug 4 2012, 11:38 am
IMO BYOND should allow lists to somehow end up in C/C++ libraries so you can pass them through a call() request, and potentially get them as return values too.

That way, it becomes even easier to write list sorting functions in C/C++ and use those in BYOND. Right now you'd have to mess around with text and have BYOND<->C/C++ mutually agree on a "separator" character to use.
#6 Aug 4 2012, 11:40 am
In response to JBoer (#5)
JBoer wrote:
IMO BYOND should allow lists to somehow end up in C/C++ libraries so you can pass them through a call() request, and potentially get them as return values too.
That way, it becomes even easier to write list sorting functions in C/C++ and use those in BYOND. Right now you'd have to mess around with text and have BYOND<->C/C++ mutually agree on a "separator" character to use.

You could just send/return the string in the same format list2params() and params2list() use.
#7 Aug 4 2012, 11:47 am
Good idea! I never thought of that. Thanks!
#8 Sep 11 2012, 10:26 am
I just wanna paste this old topic mentioning similar things.
id:132730
#9 Sep 12 2012, 11:10 am
In response to ExPixel (#6)
That's actually how my DMI Icon Info library passes data back and forth. It works surprisingly well. You can even nest lists within lists within lists.