User-friendliness is what really matters

on space_check(threshold_percentage)
    tell application "Finder"
        set the percent_free to ¬
            (((the free space of the startup disk) / ¬
                (the capacity of the startup disk)) * 100) div 1
    end tell
    if the percent_free is less than the threshold_percentage then
        tell application (path to frontmost application as text)
            display dialog "The startup disk has only " & the percent_free & ¬
                " percent of its capacity available." & return & return & ¬
                "Should this script continue?" with icon 1
        end tell
    end if
end space_check

>>17
it was an example of how trying to treat programming languages as human languages just leads to incredible amounts of wasted typing.
i'm amazed you didn't understand something so simple and obvious - actually, what am i saying? you're a macfag, ofcourse you were too stupid to realise the point.