Re: bug#24514: 24.5; Lispy backtraces

[Clément Pit--Claudel]

On 2016-12-04 10:30, Eli Zaretskii wrote:
>> From: Clément Pit--Claudel <address@hidden>
>> Date: Sat, 3 Dec 2016 17:15:22 -0500
>>
>> On 2016-12-01 21:24, Stefan Monnier wrote:
>>>> The discussion below seems to indicate that there's very little missing at
>>>> the Lisp level to be able to implement `backtrace' in Lisp; is that right?
>>>
>>> Indeed, I think all the info needed is provided by backtrace-frame.
>>
>> The C implementation of backtrace-frame seems to be linear in the index of 
>> the requested frame, so a Lisp implementation of backtrace would be 
>> quadratic in the depth of the stack trace.  Would a new function 
>> backtrace-frames that returns all frames at once be acceptable?
> 
> But such a backtrace-frames function would have to be implemented in
> C, right?  And you wanted to move the implementation of "backtrace" to
> Lisp, AFAIU.  So it sounds like we will be replacing one C primitive
> with another, or did I miss something?

I think you're correct. It would seem good to have the flexible primitive 
backtrace-frames available, and it must be in C; then we can move backtrace 
itself to lisp.

The idea is that enumerating frames must be done in C, but printing them 
doesn't need to be done there.

Clément.

signature.asc
Description: OpenPGP digital signature