Re: How to add pseudo vector types

[Stephen Leake]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Clément Pit-Claudel <cpitclaudel@gmail.com>
>> Date: Wed, 21 Jul 2021 12:54:16 -0400
>>
>> On 7/21/21 12:29 PM, Stephen Leake wrote:
>> > Yes, for both tree-sitter and wisi. wisi can take even longer if lots of
>> > error correction is required (I have a time-out set at 5 seconds). But
>> > that happens when the file is first opened; I doubt any user would start
>> > typing that fast. I know I typically take a while to just look at the
>> > text, and then navigate to the point of interest.
>>
>> I'm not sure.  We've had significant complaint in Flycheck for freezing 
>> Emacs for <1s
>
> How much "less"?  Close to 1 sec is indeed annoying, but 20 msec or so
> should be bearable.
>
> You seem to assume up front that TS (re)-parsing will take 1 sec, but
> AFAIK there's no reason to assume such bad performance.

This is for the initial parse, on a large file. No matter how fast the
parser is, I can give you a file that takes one second to parse, and
some user will have such a file (the work always expands to consume all
the resources available).

I just got incremental parse working well enough to measure it; in the
largest Ada file I have (10,000 lines from Eurocontrol):

initial parse:       1.539319 seconds
re-indent two lines: 0.038999 seconds

39 milliseconds for re-indent is just slow enough to be noticeable; I still
have algorithms to convert to be as incremental as possible.

The initial parse includes sending the full file text to the external
process over a pipe. Parsing that same large file with the command-line
parser (no emacs involved; file is memory-mapped) takes only 0.190
seconds, so there is lots of room for optimization - moving to a module
with direct access to the emacs buffer should do a lot.

In a very small file:

initial   0.000632 seconds
re-indent 0.000942 seconds

Easily fast enough to keep up with the user.

I don't have a direct comparison of tree-sitter and wisi parsing the
same file; I'll have to see if I can set that up.

--
-- Stephe