Saturday, November 23, 2019

Re: Mapping erases search count message

On 2019-11-23, Bram Moolenaar wrote:
> Gary Johnson wrote:
>
> > On 2019-08-29, Christian Brabandt wrote:
> > > On Do, 29 Aug 2019, Christian Brabandt wrote:
> > >
> > > >
> > > > On Di, 27 Aug 2019, Gary Johnson wrote:
> > > >
> > > > > On 2019-08-28, Christian Brabandt wrote:
> > > > > > On Di, 27 Aug 2019, Gary Johnson wrote:
> > > > > >
> > > > > > > I just tried exposing the search count message by removing 'S' from
> > > > > > > 'shortmess', but I couldn't see it. I discovered that it is hidden,
> > > > > > > erased and/or not updated by a couple of my mappings.
> > > > > > >
> > > > > > > nnoremap <silent> n nzv:call AdjCursor()<CR>
> > > > > > > nnoremap <silent> N Nzv:call AdjCursor()<CR>
> > > > > > >
> > > > > > > Here is a simple experiment that demonstrates the problem. Create
> > > > > > > a file, test.vim, that contains the following.
> > > > > > >
> > > > > > > set shortmess-=S
> > > > > > > nnoremap <silent> n n
> > > > > > > help map.txt
> > > > > > >
> > > > > > > Open a standard-sized, 80x24 terminal, and in it run
> > > > > > >
> > > > > > > $ vim -N -u NONE -i NONE -S test.vim
> > > > > > >
> > > > > > > Then search for "command":
> > > > > > >
> > > > > > > /command
> > > > > > >
> > > > > > > After hitting Enter, the cursor will be at the start of "commands"
> > > > > > > on line 7 and the command line will contain this:
> > > > > > >
> > > > > > > /command [1/>99]
> > > > > > >
> > > > > > > After hitting 'n', the cursor advances to line 13 and the command
> > > > > > > line stays the same, even showing "[1/>99]" when it should be
> > > > > > > showing "[2/>99]".
> > > > > > >
> > > > > > > Another 'n' advances the cursor to line 17, the screen scrolls
> > > > > > > up so that that line is at the bottom of the window, and the command
> > > > > > > line is empty--no search count message at all.
> > > > > > >
> > > > > > > I would think that <silent> would prevent the mapping from
> > > > > > > disturbing the command line, in which case this is a bug.
> > > > > > >
> > > > > > > If it's not a bug, then is there some way of defining a mapping that
> > > > > > > does not interfere with the search count message, or some way of
> > > > > > > restoring that message at the end of a mapping?
> > > > > >
> > > > > > Is that with patch 8.1.1288 included?
> > > > >
> > > > > Sorry, I forgot to include the version information. Yes, I used the
> > > > > latest version, 8.1.1933.
> > > >
> > > > Hm, I need to investigate.
> > >
> > > I see what is happening. A mapping with the `<silent>` flag will set the
> > > internal variable cmd_silent to prevent it from being output the command
> > > line. So what your mapping does is it acts like 'n' without outputting
> > > anything on the command line.
> > >
> > > But this is not what you want. You want the default behaviour of n,
> > > which does output the command to search + the new search index feature.
> > >
> > > (See the difference on the commandline between a plain `n` and a n
> > > mapped with `nnoremap <silent> n n`).
> > >
> > > So the obvious fix would be to remove the `<silent>` command. While this
> > > fixes your minimal test case, it most likely is no fix for your actual
> > > issue, that calling the AdjCursor() function will be output in the
> > > command line in addition (possibly overwriting the command line).
> > >
> > > What might work (depending on the complexity of your AdjCursor()
> > > function) is to use an expression mapping that simply returns 'n' after
> > > having done whatever action it needs to be doing. However, this might be
> > > a bit difficult since you want this to happen after the cursor has been
> > > placed.
> > >
> > > Another alternative might be a mapping like this:
> > >
> > > nmap n nzv
> > > nnoremap <silent> zv zv:call AdjCursor()<cr>
> >
> > Thanks for looking further into this, Christian.
> >
> > I don't understand how that first mapping in your alternative
> > mappings works. I thought that using nmap (not nnoremap) to map
> > n to a rhs including n would cause an infinite recursion, but it
> > doesn't.
> >
> > Those mappings solve part of the problem. That is, if AdjCursor()
> > is an empty function, they work fine--the search count message is
> > always visible. But if AdjCursor() is the actual function (which
> > scrolls the window when needed to keep the cursor at least two lines
> > from the top and bottom), then whenever the window is scrolled, the
> > message disappears.
> >
> > In fact, removing all the mappings and just executing Ctrl-E or
> > Ctrl-Y to scroll the window after a search erases the search count
> > message. I think that's a bug. I can see no reason why scrolling
> > should erase that message unless scrolling moves the cursor.
> >
> > Further, certain motion commands such as j, k and gg _don't_ erase
> > the search count message, even though it would make sense for them
> > to do so. It's weird to jump from the bottom of a buffer to the top
> > with gg and still see the last search count message in the command
> > line.
> >
> > The purpose of AdjCursor () is to scroll the window after a search
> > moves the cursor near the top or bottom of the window so as to
> > provide at least two lines of context around the cursor. (It should
> > really be named AdjWindow().) It behaves like scrolloff=2, but only
> > after certain commands. I don't want 'scrolloff' on all the time.
> >
> > That gave me an idea, a different solution to the problem:
> > temporarily enable 'scrolloff' instead of scrolling the window.
> > Here is what I just came up with and it seems to work well.
> >
> > nmap <silent> n :call ScrolloffCmd('n')<cr>
> > nmap <silent> N :call ScrolloffCmd('N')<cr>
> > function! ScrolloffCmd(cmd)
> > set scrolloff=2
> > try
> > exe 'normal!' a:cmd
> > catch
> > echohl ErrorMsg
> > echomsg matchstr(v:exception, ':\zs.*')
> > echohl NONE
> > endtry
> > set scrolloff=0
> > endfunction
>
> Looking through older problems...
>
> I tried the example with remapping "n", but it works OK for me.
> Was this problem fixed already? Or is only that example fixed and there
> a remaining problem?

There was a patch that fixed part of the problem, and I rewrote my
function to avoid another part of the problem. It's been working
fine since early September. I don't think there is any more that
you need to do. Thank you and Christian again.

Regards,
Gary

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