Check to see if the interpreter defines an object
int SLang_is_defined (char *nm)
The SLang_is_defined
function may be used to determine
whether or not a variable or function whose name is given by
em
has been defined. It returns zero if no such object has
been defined. Othewise it returns a non-zero value whose meaning
is given by the following table:
1 intrinsic function (SLANG_INTRINSIC)
2 user-defined slang function (SLANG_FUNCTION)
-1 intrinsic variable (SLANG_IVARIABLE)
-2 user-defined global variable (SLANG_GVARIABLE)
SLadd_intrinsic_function, SLang_run_hooks, SLang_execute_function