RE: GUI was Re: why Ada is so unpopular ?

["amado.alves" <amado.alves@netcabo.pt>]

<<...this doesn't work very well when you drop
into a directory with thousands of files. A smart tree widget
might just peruse "directory portions", where the tree widget
is visible (perhaps a less than trivial exercise). But I suspect
they take the easy way out, and require all entries to be loaded
in to the widget's dynamic memory...>>

A solution to this is to have and use standard iterator signatures, defined e.g. as formal packages descendants of Ada.Containers. (As an iterator is clearly an item of container design, iterator signatures belong there.)

Directory_Listing (say) builds an 'internal' iterator, and return an instantiation of the standard signature, grounded on this internal iterator. Then all is well. The Directory package would not be using the Ada.Containers 'engines', but just their specification. (The advantages include the possiblity of interaction with other standard containers e.g. perform a deep copy of a part of the tree to send to a GUI object).

However, I think Ada.Containers should provide 'real' containers with the structure and efficiency required by Directories. Even the possible cyclic graphs of directories with links. If Ada.Containers does not have this already (I don't recall), it should be a simple (!) matter of adjusting (basically, generalizing) the structures already in the reference implementation of Directories (?) and moving them to Ada.Containers.

I suspect these things don't happen because of the communication costs between the teams working on the several proposals (Containers, Directories, ASIS, ...) The costs are high, we simply don't have the means to support them, so there simply is no communication. Result: a disconnected standard :-(