[plt-scheme] 2htdp/image: above and friends
I'd like to suggest that above and friends from the 2htdp/image library
change from:
(above i1 i2 is ...) -> image?
i1 : image?
i2 : image?
is : image?
to:
(above is ...) -> image?
is : image?
This is consistent with ISL's +, and it's important for the analogy
between numbers and images that the operations remain consistent.
Also, above (as is) and apply won't work together, which I think was one
reason for ISL moving to its current + contract.
The new function would obey:
(equal? (above i) i)
(equal? (above) (circle 0 'solid 'red))
[Maybe an empty-image binding for that latter value should be in
included in the library?]
David