Re: Confusing Cursor Positions

> > The terminology used in Gobo is explained in the book
> > "Reusable Software" from Bertrand Meyer I think

Yes, the wording is almost verbatim from the class interface text in 
chapter 16.

> What about:
> 
>  -- Is it possible to move the cursor to the right?

This should be "Is it _not_ possible to move the cursor to the 
right?" When `after' is true it is impossible to move the cursor to 
the right.

> with perhaps an additional comment:
> 
>  -- (The last valid position is after the last item.)
> 
> Incidentally, 'right' and 'left' from the 'Reusable Software' 
> terminology may also be a bit ambiguous.

`forth' and `back' are not ambiguous, as they are defined in terms of 
each other, i.e. the precondition for `forth' is not after. This 
would lend to

-- Is it impossible to move cursor `forth'?

Meyer gives an informal definition of `after' in chapter 6.3.5:

"after is true if and only if the cursor ... is one position after 
the last item"

So how about?

-- Is cursor one position after the last item?

or

-- Has cursor been moved `forth' one position past the last item?

I only vote to change the comment if we all agree that

a. The current comment does not convey the correct semantics to a 
majority of people
b. The new comment obviously improves the clarity

I always thought that "Objects in mirror are closer than they appear" 
would be clearer as "Objects are closer than they appear in mirror" 
but I can't find anyone to agree with me ;-)

Brian






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