The monadic system function 君C takes a right argument which is a character string specifying a name, or character matrix of names. It returns a numeric result which is the classification of each name:
1 = line label 2 = variable 3 = function 4 = operator 5 = group 9 = class 0 = name not in use ッ1 = invalid name
Note: If 靴S is non-zero, an invalid name may be represented by 4 for compatibility with APL.68000 Level I. See 靴S for details.