1

If you execute this

cnoremap <expr> <silent> <C-S> execute(':cnoremap <c-s> ctrl-s')

and then hit /Ctrl-sCtrl-sCtrl-sCtrl-s, you'll see the search command be populated by /ctrl-sctrl-sctrl-s.

Good.

But what's special in <space> not to work like that?

After executing this

cnoremap <expr> <silent> <C-S> execute(':cnoremap <space> space')

as soon as I hit /Ctrl-s, I get E385: Search hit BOTTOM without match for: ^S.

To get the thing to work, I have to alter the command above to look like this

cnoremap <expr> <silent> <C-S> execute(':cnoremap <lt>space> space')

Why is that?

Improve this question

1 Answer 1

Reset to default
1

A map command substitutes all "angle brackets" inside. Really all of them.

Therefore, the second map gets either ctrl-s as byte#19 (which is ok) or space as byte#32 (which is a literal space to eat). And then some cryptic errors appear for the second case only.

There could be different solutions but the most straightforward one is always to use <lt> instead of < inside nested maps. This way all nested expansions will be performed in two steps.

Improve this answer
6
  • At which point does ':cnoremap <space> space' become ':cnoremap space'? In the context of cnoremap? Or in the context of execute? Or what?
    – Enlico
    Oct 21, 2022 at 18:54
  • Well, from the first paragraph of your answer, I understand it happens as soon as the mapping is created.
    – Enlico
    Oct 21, 2022 at 18:55
  • Mmm. There's still something I don't understand. Paradoxically, it is maybe why does ':cnoremap <c-s> ctrl-s' work? I mean, I don't understand what ctrl-s as byte#19 (which is ok) means.
    – Enlico
    Oct 21, 2022 at 18:57
  • @Enlico Exactly. Every map expands everything it can. Just imagine how would you program it in the most straightforward way: never check anything except "less-than" and "greater than".
    – Matt
    Oct 21, 2022 at 18:59
  • @Enlico As I mentioned above, c-s is byte#19. And it is okay. That is, you can put "control codes" right inside vim source and they will work (well, sometimes in some specific places, of course).
    – Matt
    Oct 21, 2022 at 19:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.