[XeTeX] additional beginL endL nodes in math

[Philip Taylor]

Khaled Hosny wrote:

> On Wed, Apr 15, 2015 at 08:52:38PM +0100, Philip Taylor wrote:

>> Might it not be possible to resolve this by making the new behaviour
>> optional, using a new primitive for the purpose ?
> 
> So this just penalizes the unlucky people who need to enable the special
> behaviour, I’d rather penalize everyone and have a consistent, if
> erratic in someways, behaviour.

I do not understand.  If system A performed function Y until now, yet
its designer/maintainer wishes it to perform function Y' henceforth, how
can those who wish to exploit Y' be /penalised/ by being asked to invoke
the operation specifically, rather than have it just happen and destroy
backwards compatibility ?  I see no "penalty" at all, just allowing the
informed user to make an explicit choice between the two behaviours.

Philip Taylor