How can I execute a piece of selected lines on terminal with a mapped command?

Question

I've created the following script on my vimrc file:

function! ExecuteOnTerminal() 
    if (&ft=='javascript')
        :%terminal node
    elseif (&ft=='sh')
        :%terminal bash
    elseif (&ft=='python')
        :%terminal python3
    endif
endfunction

map <F6> :silent call ExecuteOnTerminal()<CR>

It works fine... It detects the type of the file that I'm editing and when I press F6 and I'm in Normal mode it will execute the current file on a splited terminal window. However, I'd like to go beyond this functionality and detect if I currently have selected lines on Vim. if I do, I'd like to execute only the current selected lines. If I don't, I'd like to execute the entire file (executing the entire file is the current behavior).

When I try to press F6 with this script I receive the error No range allowed. Is there any way of detecting if I'm in visual mode and executing a different command for it? Or would it be better creating a new command?

Answer 1

1. "No range allowed" is due to :silent that never accepts line range, obviously. If you need to silent your command while still accepting line range you have to employ some alternative. Maybe :h map-silent, or :h map-cmd, etc.etc.

2. As your function doesn't have the range keyword it will be executed once per each line in a given range that is probably not what you want. Hence, you'd better to add range to it and to process it accordingly. See :h :func-range, :h :call, :h function-range-example and all such.

Yet another alternative is to drop line range forcefully (by :h c_CTRL-U or :h map-cmd) and then to get line numbers with bookmarks '< and '> (for Visual-mode mapping) or line(".") and :h v:count (for Normal-mode mapping).