Re: Watchpoints for emacs lisp.

["A. Soare" <alinsoar@voila.fr>]

> > I insert to the struct Lisp_Symbol a field :watched: .
> 
> So, no support for watching for an element of an array or pair to be changed, or part of a string?

Hm... I thought only to symbols, true. Not to arrays, not to numbers.

Can you use the change of an array if a symbol does not point to it? Probably yes. There exist lambda function (functions without name), but probably one can debug also the change of an array without name.


.....

> > Afterwards, in ALL functions that are able to change the value of a symbol,
> > I insert a checkpoint, which looks like that:
> > 
> > <if the symbol to change has the flag :watched: true, that call the
> > corresponding procedure of the debugger>
> > 
> > Is it ok the algorithm ? In how many obarrays should I look for the given
> > symbol ?
> 
> If you do it this way, I think having a Lisp function take a symbol in which to set the flag, and having a user-callable function which uses (interactive "S") (which asks the user for a symbol name in the main obarray), is probably a good start.  Anything that isn't in the main obarray can be provided directly in lisp by the developer.
> 
> What about changes to the property list, or function value, of a symbol?
> 

Can you figure an algorithm for checking very fast (O (0)) whether a symbol has a given property ?

Yes, surely yes, if property lists would have been implemented with fast search algo, which is not the case of emacs.  


Alin



____________________________________________________

 Les scandales de cannes, les palmes d'or, l'actualité du festival sur voila.fr http://evenementiel.voila.fr/festival-de-cannes2010/