Using Vim command to insert text to multiple lines - vim

Question

I know in visual block mode, by <S-i> (I) one can insert in multiple selected lines, however I want to achieve the same effect by a function, let's say I have a functions which can tell the three sub-visual modes (visual-character, visual-line, visual-block) as follows,
function! VisualMappingSpace()
let m = visualmode()
if m ==# 'v'
echo 'character-wise visual'
elseif m == 'V'
echo 'line-wise visual'
elseif m == "\<C-V>"
echo 'block-wise visual'
endif
endfunction
I've tried as follows but it doesn't work. I want to insert soemthing to the lines I select when I hit <space> in visual-block mode.
function! VisualMappingSpace()
let m = visualmode()
if m ==# 'v'
exec "normal y"
elseif m == 'V'
exec "normal y"
elseif m == "\<C-V>"
let g:block_insert_content = input("")
exec "normal I ".g:block_insert_content
endif
endfunction
vnoremap <silent> <Space> :call VisualMappingSpace()<CR>

Answer 1

A visual-mode mapping that enters command-line mode via : will have the visual range ('<,'>) automatically inserted. With :call, that means that your function is invoked once per selected line. You should have noticed via the repeated queries.
To avoid this, insert <C-u> into your mapping; it clears the range.
Second problem: When you insert the queried text, you need to re-create the selection (your mapping left visual mode for command-line mode, remember?) via gv; then, I will work:
function! VisualMappingSpace()
let m = visualmode()
if m ==# 'v'
exec "normal y"
elseif m == 'V'
exec "normal y"
elseif m == "\<C-V>"
let g:block_insert_content = input("")
exec "normal gvI ".g:block_insert_content
endif
endfunction
vnoremap <silent> <Space> :<C-u>call VisualMappingSpace()<CR>
Also note that there is an additional space character before your queried text; I'm not sure you want that: gvI ".