Re: [Gretl-devel] isnull with null list isn't true

Dear all, isnull Returns 0 if name is the identifier for a currently defined object # from function reference ? string nstr = null Generated string nstr ? eval isnull(nstr) 0 I think the name of the function is confusing since it may make one think it tests whether object=null There's actually not computing problems, only potentially misguiding name  Now I think, the simplest way to proceed is enlarge help text for this function Oleh  27 жовтня 2015, 11:21:31, від "Sven Schreiber" < svetosch(a)gmx.net >: [I've also read your other message from yesterday.] Am 26.10.2015 um 22:13 schrieb Allin Cottrell: Given the backwards-compatibility issues especially with 'null' as an established initializer for lists (less so for bundles), maybe the best solution is to rename isnull(), for example to isobj() -- or to be precise, 'isnull(X)' would be equivalent to '!isobj(X)'. The alias isnull() could be deprecated eventually. (And BTW/OT: perhaps 'isobj(b.X)' could also be an alias for 'inbundle(b, "X")'.) Again, I don't think it would be wise to replace the 'null' keyword here. But maybe 'empty' could be allowed as an alias in this context (for lists and bundles). (Another BTW/OT: This might also work for arrays. Saying 'matrices ms = array(4)' is redundant in a sense because 'matrices' already means that it's an array. This could be 'matrices ms = empty(4)' instead.) ... Logically, yes. But I suspect it would imply a pretty hefty compatibility-breaking problem for existing real-world functions. (Perhaps it could be used somehow that optional list arguments are an exception already, they have their own paragraph in the guide and they don't have to / cannot be passed in pointer form. Maybe introduce the 'empty' keyword there as well, with 'null' as an alias for compatibility?) ... Yes, then the example would go like this: <hansl> bundle b2 = null # or = empty in the future perhaps if !isobj(b2) # would be false, because b2 exists print "b2 no" # would not be printed endif </hansl> ...and this would feel natural and not confusing. thanks, sven _______________________________________________ Gretl-devel mailing list Gretl-devel(a)lists.wfu.edu http://lists.wfu.edu/mailman/listinfo/gretl-devel