Re: indentation via text or overlay property?

[Kevin Rodgers]

Stefan Monnier wrote:

> > > > > > "Kevin" == Kevin Rodgers <ihs_4664@yahoo.com> writes:
> > Is there a way to implement indentation via a text property like left-margin
> > or an overlay property like before-string?
>
> (put-text-property start end 'display '(space :align-to N))
>
> will make the text between `start' and `end' appear like a space
> that ends at column N.


Cool!  But since those spaces are displayed instead of the original text (not
in addition to it), I don't see how to use that to implement indentation.

For example, let's say I have a <foo> tag at the beginning of a line that I
want displayed at column 6.  If I specify '(space :align-to 5) for the
display property at the position of "<" in the buffer, it gets indented like
I want except that the "<" is no longer visible.  And apparently I can't use
a value like

        (list '(space :align-to N) (buffer-substring start end))

to get both the spaces and the original text displayed.

> This is at least documented in the NEWS file of Emacs-21.1, and
> I'd expect there to be something about it as well in the elisp manual.

Thanks for the pointers.  Is the correct way to test for this feature:

        (>= emacs-major-version 21)

--
<a href="mailto:&lt;kevin.rodgers&#64;ihs.com&gt;";>Kevin Rodgers</a>