Hello Joris,

I remember struggling quite often with this behavior, however I don't recall on which expressions exactly :/

I think it was mostly in equations of the form

 x y z,(extra space) (forall) a in b,

where it is very natural to type a space. I can see how the "space + comma" shortcut makes sense, however it could be a bit confusing to new users, since it is a shortcut they will almost certainly activate unintentionally. Maybe it would make sense to add a first-time warning dialog explaining such behavior.

Jan

On 30.09.2011 07:36, Joris van der Hoeven wrote:

On Sun, Jun 26, 2011 at 04:44:44PM +0200, Jan Lellmann wrote:

I noticed that recent versions of Texmacs exhibit a strange
behavior: When I type a comma "," in an equation followed by space,
the comma disappears. This is quite annoying. Is it intended
behavior, and if yes, why?

Yes, this is the intended behaviour.
The shortcut ", " stands for an invisible comma.
For instance, "a_i, j" allows you to type the matrix entry $a_{ij}$.

In math mode, users are not intended to manually enter spaces
around commas or other operators, except if you want to explicitly
apply a function. The typesetter knows about the amount of whitespace
to put around commas and operators. In other words, type "f(x,y)"
and not "f(x, y)"; also type "x+y", not "x + y".

I agree though that the behaviour may seem unnatural;
maybe I should only activate it in semantic editing mode.
On the other hand, it is true that spurious commas are
*THE* major nuisance to parsing math formulas.
It is really a nasty habit. An alternative would be
to simply ignore such spaces.

On this occasion, I would re-ask users to try the semantic
mathematical editing mode (see explantions in the documentation
on typing mathematical formulas); it remains useful to have
more feedback on this issue.

Best, --Joris