Problem with conditional mapping

Question

I am trying to reproduce this vimscript code

function! NormalRemap()
    :nnoremap <silent> <nowait> I I
    :nnoremap <silent> <nowait> a a
    :nnoremap <silent> <nowait> o o
    :nnoremap <silent> <nowait> O O
    :nnoremap <silent> <nowait> c c
    :nnoremap <silent> <nowait> C C
    :nnoremap <silent> <nowait> s s
    :nnoremap <silent> <nowait> S S
    :nnoremap <silent> <nowait> v v
    :nnoremap <silent> <nowait> V V
    :nnoremap <silent> <nowait> r r
    :nnoremap <silent> <nowait> R R
    :nnoremap <silent> <nowait> q q
endfunction

function! NormalUnmap()
    :nnoremap <silent> <nowait> I <nop>
    :nnoremap <silent> <nowait> a <nop>
    :nnoremap <silent> <nowait> o <nop>
    :nnoremap <silent> <nowait> O <nop>
    :nnoremap <silent> <nowait> c <nop>
    :nnoremap <silent> <nowait> C <nop>
    :nnoremap <silent> <nowait> s <nop>
    :nnoremap <silent> <nowait> S <nop>
    :nnoremap <silent> <nowait> v <nop>
    :nnoremap <silent> <nowait> V <nop>
    :nnoremap <silent> <nowait> r <nop>
    :nnoremap <silent> <nowait> R <nop>
    :nnoremap <silent> <nowait> q <nop>
endfunction

function! DoxyGenComment()
    :call NormalRemap()
    :Dox
    :call NormalUnmap()
endfunction

(which works fine) with the following one:

let mymap = 1

function! DoxyGenComment()
    let g:mymap = 0
    :Dox
    let g:mymap = 1
endfunction

:nnoremap <expr> I (mymap == 1) ? '<nop>' : 'I'
:nnoremap <expr> a (mymap == 1) ? '<nop>' : 'a'
:nnoremap <expr> o (mymap == 1) ? '<nop>' : 'o'
:nnoremap <expr> O (mymap == 1) ? '<nop>' : 'O'
:nnoremap <expr> c (mymap == 1) ? '<nop>' : 'c'
:nnoremap <expr> C (mymap == 1) ? '<nop>' : 'C'
:nnoremap <expr> s (mymap == 1) ? '<nop>' : 's'
:nnoremap <expr> S (mymap == 1) ? '<nop>' : 'S'
:nnoremap <expr> v (mymap == 1) ? '<nop>' : 'v'
:nnoremap <expr> V (mymap == 1) ? '<nop>' : 'V'
:nnoremap <expr> r (mymap == 1) ? '<nop>' : 'r'
:nnoremap <expr> R (mymap == 1) ? '<nop>' : 'R'
:nnoremap <expr> q (mymap == 1) ? '<nop>' : 'q'

This last one doesn't work (DoxygenToolkit.vim doesn't generate the correct comment syntax since it doesn't see the correct mapping).

What is wrong in my second approach with conditional mapping ?

A couple of minor points to add to dedowsdi answer: if you are in a vimscript file you don't need the : in front of your commands. Also I think you may have a scope issue on your variable: you mix g:mymap and mymap, I'm not sure what's the default scope for a variable without prefix but anyway it is a good practice to explicitly specify a variable scope. Finally you may be interested in reading How to debug a mapping. — statox, May 02 '19 at 08:43

score 2 · Answer 1 · answered May 02 '19 at 02:33

AFAIK, <nop> should be used without <expr>. If you want to use <expr>, just return an empty string:

:nnoremap <expr> I (mymap == 1) ? '' : 'I'

By the way, you may consider to do it like this:

let forbiddens = 'IaoO.....'
for oper in split(forbiddens, '\zs')
  exec 'nnoremap ' . oper . ' <nop>'
endfor

Problem with conditional mapping

1 Answers1