Slow performance with very long lines

[minad]

To keep in mind, see radian-software/selectrum#436 (comment). Maybe nothing can be done for certain patterns which may necessarily result in high complexity. Needs further investigation.

[oantolin]

One good test to try would be to test (setq completion-style '(orderless) orderless-matching-styles '(orderless-flex)) vs (setq completion-styles '(flex)). If, as I suspect, they are comparably slow, it would be an indication that there isn't much to be done about this.

I wasn't fully aware of my motivation at the time, but in my personal configuration the expensive styles like initialism and flex are always introduced by explicit syntax. It must have been that I felt those were slower (but I never deal with long lines, so the difference is pretty small).

[minad]

I am not using flex by default since it seems so much more expensive. It always leads to a noticeable slowdown. But initialism is activated always. I am using the default settings with the explicit syntax for flex~ and literal= and !negated literal.

[oantolin]

My syntax for flex even has two characters! Again, probably subconsciously I felt it was even slower than initialism. I use a single (either leading or trailing) . for initialisms but curly braces for flex (I also use electric-pair-mode so I only type one brace).

[minad]

It is not unreasonable to use multiple characters for the explicit styles in order to avoid interference with regexps. And usually when I do an explicit style switching, typing two letters wouldn't make a difference.

[minad]

Just stumbled over this: https://github.com/doyensec/regexploit 😆

[minad]

What about removing initialism from orderless by default? Instead recommend creating special orderless-styles which include more matching styles? And in any case we have the matching style dispatchers.

(orderless-define-completion-style orderless+initialism
  (orderless-matching-styles '(orderless-initialism orderless-literal orderless-regexp)))

(setq orderless-matching-styles '(orderless-literal orderless-regexp))

(setq completion-category-overrides
      '((file (styles partial-completion orderless+initialism))
        (command (styles orderless+initialism))
        (buffer (styles orderless+initialism))
        (consult-multi (styles orderless+initialism))
        (symbol (styles orderless+initialism))))