Return a |List|, which is the stack of syntax items at the position {lnum} and {col} in the current window. Each item in the List is an ID like what |synID()| returns. The first item in the List is the outer region, following are items contained in that one. The last one is what |synID()| returns, unless not the whole item is highlighted or it is a transparent item. This function is useful for debugging a syntax file. Example that shows the syntax stack under the cursor: for id in synstack(line("."), col(".")) echo synIDattr(id, "name") endfor When the position specified with {lnum} and {col} is invalid nothing is returned. The position just after the last character in a line and the first column in an empty line are valid positions.