toupper package:sbv

Convert to upper-case. Only works for the Latin1 subset, otherwise returns its argument unchanged.

>>> prove $ \c -> toUpperL1 (toUpperL1 c) .== toUpperL1 c
Q.E.D.

>>> prove $ \c -> isUpperL1 c .=> toUpperL1 (toLowerL1 c) .== c
Q.E.D.