Re: [Gzz] New PEG: prefix_argument--benja

[Tuomas Lukka]

On Sat, Nov 16, 2002 at 06:04:48PM +0100, Benja Fallenstein wrote:
> Tuomas Lukka wrote:
> 
> >>Bindings usually use the prefix argument in one of two ways:
> >>
> >>  - "Prefix or other:" If there is no prefix argument, the cell
> >>    accursed in the other window is used instead. Examples:
> >>    Connect, Put (see ``containment--benja``), Go (the 'g' key).
> >>  - "Prefix or this:" If there is no prefix argument, the cell
> >>    accursed in *this* window is used instead. Examples:
> >>    Hop, Break, Clone, Delete, Excise, New Cell.
> >>   
> >>
> >
> >This feels a bit complicated way to explain this. I agree with 
> >the result but it *might* be better to explain this instead by
> >saying that if there's no marked cells, the prefix argument
> >is either the this or other.
> >
> 
> The good point about this way is that we can directly derive function 
> names from this explanation (prefixOrOther(), returning a list of 
> cells). If we say that the prefix argument *is* the cell in this or the 
> other window, naming the functions becomes harder...
> 
> Or hmm, we could say that each window has its own prefix arg, and the 
> flavors are taking this window's (thisPrefix()) or the other window's 
> (otherPrefix()). Hmm. I don't think that makes it easier to understand...

Yes, from a programmer's point of view your original way is good.
But from an user's point of view it seems very complicated.

> >Hmm... how do I search and then leave the search result in the background
> >for a moment?
> >
> 
> Mark it (in a different mark set if you have cells marked already).

Ok

> >Actually, I'm not completely sure that using the marked cells like this
> >is good, without being specific: I'd prefer saying
> >
> >     "Ok, now with the marked cells, do X"
> >
> >instead of accidentally using the marked cells when moving around to 
> >mark cells.
> 
> Hm, I don't quite follow yet. Can you give an example where this would 
> be a problem?

E.g. if "GOTO" function takes prefix parameter, or other window's cell.

Now, if you're starting to mark cells for some operation, suddenly
doing 'goto' takes you to a different place from where you intended
to go.

Marks should only be prefix args if explicitly asked for.

        Tuomas