I know you can use
set foldcolumn=1
to enable fold column
but is there a way to automatic turn it on only when there are folds exist in the file?
Most probably you can create a function to check if the file has any folds, like:
function HasFoldedLine()
let lnum=1
while lnum <= line("$")
if (foldclosed(lnum) > -1)
return 1
endif
let lnum+=1
endwhile
return 0
endfu
Now you can use it with some autocommand
, e.g.:
au CursorHold * if HasFoldedLine() == 1 | set fdc=1 | else |set fdc=0 | endif
HTH