Running Through Things, index and last?

Authoring Inform 7
1

Is there a way to target the index or the first or last item while running through things?

something like:

...
     repeat with item running through things:
          if the item is x index:
               say "this is item number [x index]";
          if the item is last:
               say "this is the last item";
2

It doesn’t seem very idiomatic to Inform 7, but I suppose you could increment a counter as you go through the repeat loop and use that as the index.

3

Oh… right. Inform makes me feel dumb.

Even if I did that, how do I compare the index to the length of the list? Do I need to build that too somehow or is there already an equivalent of something like “something.length” in Inform that can be applied to a list?

4

You could refer to “the size of the list”.

Just wondering, what do you need this for? The repeat loop won’t give you the objects in any meaningful order.

5

The usual approach is to maintain the index manually:[code]There is a room; there is a container; there is a supporter; there is a device.

When play begins:
let the ultimate index be the number of things [as Draconis suggested] minus one;
let the index be zero;
repeat with the item running through things:
say “[The item].”;
if the index is two:
say “-- This ([the item]) is item number two.”;
if the index is the ultimate index:
say “-- This ([the item]) is the last item.”;
increment the index.[/code]

Edit: Okay, you people already got three posts in while I was writing this.
Further edit: Fixed a silly spelling error.

6

I’m having trouble getting this to work in the context I originally encountered the issue for. This code was drawn up in a different thread I opened, but I thought the issue here (dealing with lengths of lists) was specific enough for its own thread.

How can I insert index checking and last into this?

To say descriptive (L - list of objects):
	repeat with the item running through L:
		say "[description of the item]".

I tried a similar syntax to what you have there, eu, but it doesn’t like it (says it can’t understand “number of objects in L”, but I don’t know what the proper syntax for referencing that would be):

To say descriptive (L - list of objects):
	let the ultimate index be the number of objects in L minus one;
        let index be 0;
	repeat with the item running through L:
                if the index is the ultimate index:
			say " and [description of the item]";
		otherwise:
                        say "[description of the item], ";
7

“number of entries in L” is what you want.

8

Indeed it was! Thanks all!

9

You don’t necessarily need to increment the index manually:

To say descriptive (L - list of objects): repeat with index running from 1 to the number of entries in L: if the index is the number of entries in L: say " and [description of entry index in L]"; otherwise: say "[description of entry index in L], ".