turn lower-case characters into upper-case characters
Major Section:  ACL2-BUILT-INS

(Char-upcase x) is equal to #A when x is #a, #B when x is #b, ..., and #Z when x is #z, and is x for any other character.

The guard for char-upcase requires its argument to be a standard character (see standard-char-p).

Char-upcase is a Common Lisp function. See any Common Lisp documentation for more information.

To see the ACL2 definition of this function, see pf.