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.