Using ':-x' and ':-y' is just what I need. Thanks a lot!

Thanks Jacques and Doug for your references. I rather like the 5-column-structure in Maple Classic. What I was asking for, though, was a reference to the "What's new" going back, as suggested by Jacques, to Maple 4.0. Prior to checking out your references I thought that there was some single place for these hidden gems, but now I suppose that I have to have installed on my computer all versions 4.0+ to find those. That is probably never going to happen as I have on disk only Maple 9.5 and Maple 11; even though I started using Maple V I jumped, after quite some years, obviously, straight to Maple 9.5, and the floppy disks on which was Maple V have either been formatted or thrown out a long time ago.

Thanks Jacques and Doug for your references. I rather like the 5-column-structure in Maple Classic. What I was asking for, though, was a reference to the "What's new" going back, as suggested by Jacques, to Maple 4.0. Prior to checking out your references I thought that there was some single place for these hidden gems, but now I suppose that I have to have installed on my computer all versions 4.0+ to find those. That is probably never going to happen as I have on disk only Maple 9.5 and Maple 11; even though I started using Maple V I jumped, after quite some years, obviously, straight to Maple 9.5, and the floppy disks on which was Maple V have either been formatted or thrown out a long time ago.

What I would like is being able to extract from the indexing function some information (some attributes, having now learned the existence of those) that uniquely determine its behaviour, because, as you correctly write, it makes no sense to try to figure out what an indexing function does by looking at its code.

I am afraid that I will never achieve the necessary self-discipline for doing that. But, of course, you are quite right.

I am afraid that I will never achieve the necessary self-discipline for doing that. But, of course, you are quite right.

Thanks for the nice tip. But where is "Whats new"?

Thanks for the nice tip. But where is "Whats new"?

I think you have some important points concerning how to organize such information, and concerning how to find something in a deterministic manner when you do not know what you are searching for. Thanks for the link to Robert Israels database.

I think you have some important points concerning how to organize such information, and concerning how to find something in a deterministic manner when you do not know what you are searching for. Thanks for the link to Robert Israels database.

Thanks for that very specific reference to the help text. Even though I quite probably have looked over the "Sets and Lists" help page before, I have never noticed that detail. Maybe that should be a lesson to me to read a little more meticulously.

Thanks for that very specific reference to the help text. Even though I quite probably have looked over the "Sets and Lists" help page before, I have never noticed that detail. Maybe that should be a lesson to me to read a little more meticulously.

I am slowly coming around, beginning to think that using attributes on the Arrays of mine is the correct way to proceed because it avoids that the arguments (the raw data you refer to) "flap in the breeze", unconnected with the object which they (partly) determine. But what do you think about the last paragraph of mine concerning adding some new functionality to the Array constructor?

Thanks for that trust of yours.

Using {L[ ]} instead of convert(L,set) is very neat, and a complete surprise to me. Where, Doug, did you originally pick up this knowledge? Like me, attending this forum, or? To me such a property is something that I would never guess, only stumble upon by accident, but maybe it is just my imagination that is poor. Anyway, coming to think of it, it probably having been suggested before by others, I think it would be nice to have some place where all these tricks of the trade could be collected side by side, instead of them being scattered all over this forum.