required vs optional

[Peter Rice]

James Bonfield wrote:
> I think this is where the confusion comes from. ACD is designed for command
> lines where each question is presented one at a time, whereas I'm dealing in
> GUIs where the questions need to be shown all at once. For added complexity
> the users may answer questions out of order.

ACD is intended to cope with both. It forces the application to demand all
input at the beginning. All we need to do is tweak whatever is needed to make
GUIs comfortable.

> Would you have any objections to me making use of a needed: attribute?

Can we make opt/req do what you want? The original intention was to use opt
for this (with an expression if necessary).

> > But you can be sure that the command line version will process everything in
> > one pass so all the information is in the ACD file.
> 
> But above you indicated that some information is known only by the application
> and so it isn't in the ACD file.

Only in so far as the application can get a value for any option, and do
whatever it wants with it.

In effect, by greying out options, you are forcing EMBOSS to use the default
value (which is what I would expect).

> The main problem is that the natural grouping is separated. Eg pepwheel -h
> indicates that the options tab would contain how to plot the wheel, but
> whether to perform the plot is in a different tab (advanced).

Hmmm. Well, we could make that option an opt:Y as well but it seems your tab
system is rather artificial if you only have required and optional tabs. Is
this fixed more easily by the option groups we were discussing earlier?

> Also for syco -graph and -outfile are both listed as mandatory, and yet the
> program will only ever use one or the other and never both (depending on the
> advanced parameter -plot). This would be rather confusing to the user.

Help will list them as mandatory because they both could be true.

When you run "syco -help" is has no way to guess what the value of "plot" will
be.
Your interface can be more cunning by greying out -graph unless -plot is
selected (ah, but as it is not currently optional you will not display it)

Question: can you avoid greying out all options that are used in dependencies
(that appear as $(name) or $(name.something) in the ACD definitions) ?

-- 
------------------------------------------------
Peter Rice, LION Bioscience Ltd, Cambridge, UK
peter.rice at uk.lionbioscience.com +44 1223 224723