Context sensitive help the *right* way..

["Blad, John Erling" <john erling blad aftenposten no>]

I gess everyone, including myself, has made a context sensitive
help system one time or another. Nearly every such system I know
about do it by some sort of callback-wrapper and redirects the
query to a local hypertext browser or something similar. This is
very simple and very efficient for "what is this" - type of queries.

The obvious problem surface when the user

  o isn't interested in the present state but in some future state
  o isn't interested in the present state but in some state in the past
  o don't know what to do
  o try to do something he cant in the present state
  o ...
  o ...

I gess the problem is (at least) "how can the present state be
represented so it..."

  o gives hint's about what the user tries to do
  o has information about how he reached the present state
  o has information about the present state
  o is simple to use (for the programmer)
  o don't impose a speed penalty
  o ...

One (rather simple solution) is to implement a stack of hints. Operations
in the application adds and removes hints as it enters and leaves states.
This is really nothing more than the initial description of a context
sensitive help system but with a list of previous states. It can also be
helpfull if you try to generate help on-the-fly.

>From the programmers point of view this can be implemented as
create-destroy pairs and push-pop function pairs.

Obvious problems are (at least) the stack which is not a first-in-last-out
but something like first-in-nearly-last-out or a history list. In other
words, what you try to pop may not be the last item in the list, and some
time you will "forget" to pop items.

John