APIs are in fact copyrightable. However there is a limit to their copyrightability, and the bstraction-Filtration-Comparison test is the standard legal test in the USA to try to distinguish between copyrightable elements and non-copyrightable elements.
in reply to Re: Copyright on languages
in thread Copyright on languages
Of course the line between artistic expression and the effect of the code is drawing lines in the sand that don't really exist. But these imaginary lines are supported by lawyers and judges, which can cost you a lot of money.