Eu usei o FastScripts para atribuir um atalho para este script:
set text item delimiters to linefeed
tell application "AppleScript Editor" to tell document 1
set input to its text
set {c1, c2} to character range of selection
if c1 is 0 then
set {p1, p2} to {1, 1}
else
set p1 to count paragraphs of text 1 thru c1 of input
set p2 to count paragraphs of text 1 thru c2 of input
if p1 is not p2 and {return, linefeed} contains item c2 of input then set p2 to p2 - 1
end if
set selection to paragraphs p1 thru p2
do shell script "input=" & quoted form of (paragraphs p1 thru p2 of input as text) & "
if [[ -z $(sed -E '/^[[:space:]]*($|#|--)/d' <<< \"$input\") ]]; then
sed -E 's/^([[:space:]]*)(#|--)[[:space:]]*/\\1/g' <<< \"$input\"
else
sed -E 's/^([[:space:]]*)/\\1--/g' <<< \"$input\"
fi" without altering line endings
set contents of selection to result
end tell