Cursor/tab character display problem

[Gunnar Ritter]

Gunnar Ritter <Gunnar.Ritter at pluto.uni-freiburg.de> wrote:

> > > it consistently, but it seems it cannot.
> > The terminal can and does do it consistenly. In this case it's the
> > application (your vi) that doesn't use tabs consistently.
> This is not just my vi. All derivatives of the original vi behave
> that way.

Moreover, there is a well-known standard defining terminal operations,
ISO 6429/ECMA-48, freely available at
<http://www.ecma-international.org/publications/standards/Ecma-048.htm>.
I'd assume that rxvt-unicode still intends to implement it.

Reading this standard makes it quickly clear that the concept of a tab
character is the wrong approach at all. What ECMA-48 defines is not
operation on tab characters, but 'tabulation' and 'tabulation stops';
i. e. a method to define character positions on a line (p. 7,
4.2.67-4.2.68).

What vi does is thus perfectly correct: It uses the tab character to
move the cursor to a _tabulation stop_. This does not imply that any
change in the size of the cursor should be performed. It just implies
a cursor movement.

	Gunnar