mailing-list for TeXmacs Users

[Joris van der Hoeven <address@hidden>]

Dear Alvaro,

On Tue, Nov 02, 2010 at 05:37:40PM +0100, Alvaro Tejero Cantero wrote:
> > These are all minor issues, but some of them are annoying. Otherwise
> > the experience is quite smooth!
> 
> In fact is a bit more complicated for the semantic mode.
> 
> * Expressions such as f(x,y) don't allow separate selection of the
> argument of the function (e.g. for changing the color)

I don't understand. In the SVN version, I manage to select
the subexpressions "x", "y", "x,y" and "f(x,y)".

> * and sometimes the new rules disallow selections e.g. in 1/x*y:
> you cannot select the product to parenthesize it.

It is not clear to me yet if it is more natural to select operators
together with their arguments or not. This can be easily changed though.

On the other hand, you are *not* allowed to select "x*" or even "x*y",
but only full subexpressions (indeed, 1/x*y is traditionally
parsed as (1/x)*y).

In fact, even in x*y*z, it is not possible to select "x*y",
because associative operators select all their arguments at once.
This decision may be more controversal. With some effort,
it would be possible to select both "x*y" and "y*z".
As a beneficial side-effect, it would become apparent that 1/x*y
is parsed as (1/x)*y, since only "1/x" would be selectable and not "x*y".

> This causes the problem that you cannot first type and then correct
> (impossible selections) but rather have to type 'correct' formulas
> from the beginning.

Yes, probably I should strictly stick to the rule that *any* meaningful
subexpression can be selected.

> It quite changes the way one types expressions and I'd say it will be
> a no-go for many people. Is there a workaround that makes everybody happy?

For the moment, at least the semantic editing feature will remain optional.
The option might even be split up in several independent options on
how to select subexpressions, how to render the innermost expression, etc.

In fact, I need more user feedback in order to understand what
will be natural and useful. Please continue your testing and let me know.
I am also interested to know whether the "automatic upgrading" options
work well. I intend to apply all of them by default, except for
"Insert missing invisible operators", which might be a bit too agressive.

Best wishes, --Joris