^char #^

	Returns macros ^char^ equal to the n-th lower case letter of the
	alphabet and ^CHAR^ equal to the n-th upper case letter, where ^n^
	refers to the token, ^#^.
	^char 1^ returns ^$char="a"^ and ^$CHAR="A"^ and ^char 26^ returns
	 ^$char="z"^ and ^$CHAR="Z"^.