cc: [email protected] Subject: Re: Re: [ast-developers] [RFE] var.__ to access the parent variable of a type or compound variable --------
> On Mon, Jul 22, 2013 at 1:28 PM, Cedric Blancher > <[email protected]> wrote: > > Forwarding the proposal. Wendy's idea to use varname.__ as name to > > reference a compound/type variable's parent is IMO *great*. > > > > For example: > > > > compound c1=( compound c2=( integer i=5 ) ) > > nameref ni=c1.c2.i # reference i > > nameref nc2=ni.__ # accesses c2 though i > > nameref nc1=ni.__.__ # accesses c1 through i > > Erm... I like the idea very very much because it solves a few things > with big variable trees and (performance) scalabilty... > > ... but the question is... can var.__ be implemented in a way which > avoids going through any name lookup ? My worry is that it won't save > much CPU time if it operates via name lookup (e.g. does the nval API > have a way to do a |np_getparentnode()| ?). > > ---- > > Bye, > Roland > > -- Currently compound variable do not contain a pointer to the parent so I see little advantable to adding var.__ since it would be slower than creating a name reference to the parent via ref=${var%.*} However, if I change this and store a pointer to the parent, then using having a syntactical means of referencin it would be useful. Using __ removes the ability to have __ as a subvariable. Perhaps ${var..} could refer to the parent. David Korn [email protected] _______________________________________________ ast-developers mailing list [email protected] http://lists.research.att.com/mailman/listinfo/ast-developers
