returns the state of the symbol named by name. Returns BAD if name is not a valid REXX symbol. Returns VAR if it is the name of a variable (that is, a symbol that has been assigned a value). Otherwise returns LIT, indicating that it is either a constant symbol or a symbol that has not yet been assigned a value (that is, a literal).
As with symbols in REXX expressions, lowercase characters in name are translated to uppercase and substitution in a compound name occurs if possible.
/* following: Drop A.3; J=3 */
SYMBOL('J') -> 'VAR'
SYMBOL(J) -> 'LIT' /* has tested "3" */
SYMBOL('a.j') -> 'LIT' /* has tested A.3 */
SYMBOL(2) -> 'LIT' /* a constant symbol */
SYMBOL('*') -> 'BAD' /* not a valid symbol */