bug#36566: 27.0.50; debug is sometimes horribly slow

[Stefan Monnier]

Lars Ingebrigtsen [2022-05-16 03:00:45] wrote:
> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>> Maybe it would.  I tend to think we should focus the C code on printing
>> data quickly and in a `read`able way (i.e. in sync with `lread.c`) and
>> benefit from the comfort of ELisp for the implementation of the
>> human-readable version of the printout where performance is not as
>> important because we will truncate long outputs anyway.
> Well, OK...  but why does edebug use cl-prin1 then when stepping through
> code?

Because what is printed is intended to be read by a human rather than by `read`.

> Stepping through code should be fast, and we don't really care
> that much about the prettiness of the values were displaying then.

I think we do care to see closures printed in a human-understandable
way, for example.

And with a `char-length` constraint the output should always be fast.


        Stefan