[Python-Dev] The impact of '@' on Leo

[Edward K. Ream]

> I've really only managed to look at Leo much once, and Edward was sitting
next
> to me at the time.

Hi Fred.  Sitting next to you at the sprint was one of the most enlightening
things I have done in a long time.  I hope the next time we sprint together
you'll be able to use Leo much more easily with cvs.  I've spent that last
six months on @thin, which should help a lot...

>  Leo doesn't store Python code in a Leo document as any
> sort of embedded object that's labeled as Python code as far as I can tell
> (though it may in it's data model); it just more text, and can have
> @directives like any other text.  I think this is inherently a risky
approach
> to the data; there needs to be at least a way to say that some portion of
the
> data is some other text format embedded into the Leo document.

.leo files are XML files.  The only thing that matters in that context is
that the xml escapes are handled properly.  What matters for the integrity
of data in derived files is that uses don't mess with the so-called sentinel
lines.  These lines "carry" the outline structure.  Destroy those lines,
destroy something essential.

Leo has a number of ways of recovering partially from such destruction, but
the fact remains that uses insert, delete, fold or mutilate sentinel lines
at their own risk.  It's as simple as that.  Sentinel lines start with #@ at
present, and it's conceivable that they will always do so, even if @ gets
used for something in Python.

> I'm sure Edward can find a way to make things work for Leo users, but I
hope
> the .leo files have some sort of format version indicator to make
upgrading
> relatively easy for Leo users.

Actually, both .leo files and derived files have various format indicators.
However, the format of .leo files hasn't changed significantly enough to
need a new number in years.  Allowing different lead-in strings for Leo
directives will have absolutely no effect on the format of .leo files.

Edward
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Edward K. Ream   email:  edreamleo at charter.net
Leo: Literate Editor with Outlines
Leo: http://webpages.charter.net/edreamleo/front.html
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