let whitespace = '\s*';
let main = '(?<main>\S(.*\S)?)';
let main_anything = '(?<main>.*)';
let main_right = '(?<main>(.*)?\S)';

def trim ('^' + whitespace + main + whitespace + '$'):
    main
where
    "   inner  " -> "inner";
    "   space inside  " -> "space inside";
    "" -> ();
    "     " -> ();
    ws + "inner" + ws -> "inner" for ws in ["  ", " ", ""];
    " " + ending -> ending for ending in ["e", ";", "ending"];
    starting + "   " -> starting for starting in ["s", ";", "starting"];
end

def trim_left ('^' + whitespace + main_anything):
    main
where
    whitespace + "inner" + whitespace ->
        "inner" + whitespace
        for whitespace in ["  ", " ", ""];
end

def trim_right (main_right + whitespace + '$'):
    main
where
    whitespace + "inner" + whitespace ->
        whitespace + "inner"
        for whitespace in ["  ", " ", ""];
end