From: "Daniel H. Luecking" 
On Tue, 27 May 1997, Eric Stork wrote:
> The command IsBlockMarked() has four returns:
>                 _INCLUSIVE_
>                 _NONINCLUSIVE_
>                 _LINE_
>                 _COLUMN_
> 
MarkChar() produces a noninclusive character block, while MarkStream()
produces an inclusive character block. Both commands mark all the
characters in the file from one point to another, the only difference is
whether the current cursor position (at the time the command is given) 
is _included_ in the block.
MarkChar() and Mark(_NONINCLUSIVE_) are equivalent commands, and
MarkStream() and Mark(_INCLUSIVE_) are equivalent as well.
Actually, the term "noninclusive" can be a little misleading, since only
the cursor position closest to the end of the file is not included. If
you issue Mark(_NONINCLUSIVE_) at one position, then back up and isuue
it again, then the first position is not in the block, while the second
one (nearer the beginning) is. I prefer to think of the left edge of the
cursor as defining the limits of the block. 
For an _INCLUSIVE_ block I think of the whole cursor being used.
> The meaning of _LINE_ and _COLUMN_ is clear.  But I can't find an
> explanation of the meaning of _INCLUSIVE_ and _NONINCLUSIVE_.
> 
> Why do I care?  Well, in implementing TSE_CAL.S I found
> that _LINE_ blocks cause it to lock up.  I solved my immediate
> problem by changing line 115
> from:
>  If ((isBlockMarked() == FALSE)    // Be sure there is a Block
> to:
>  If ((isBlockMarked()==_COLUMN_)==FALSE) // Be sure there is a ColBlock
> 
> But in working out that solution I came across the _INCLUSIVE_ &
> _NONINCLUSIVE_ block characteristics that I don't understand and can't
> find an explanation for.
> 
> Guidance would be appreciated.
> 
> Eric
> 
> ----------
> Eric Stork
> e-mail address: estork@erols.com
> 
> 
Dan Luecking -------->-------->-------->-------->-------->--------v
Mathematical Sciences  <---+    luecking@comp.uark.edu            |
Univ. of Arkansas      <---|    http://comp.uark.edu/~luecking/   |
Fayetteville, AR 72101 <---+--<--------<--------<--------<--------<
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