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Andre van Tonder <andre@xxxxxxxxxxxxxxxxxxx> writes: > > Hi Mike, thanks for the comments. > > > I'd like to suggest that compound expressions be represented by an > > opaque type rather than by pairs. This would ensure a modicum of > > abstraction, and would *really* make comprehensive the ability of all > > syntax objects to carry location information. > > The current representation does allow source tracking for compound syntax > objects. One would make the reader put the location of each node (pair or > vector) in a hash table. Each evaluation of a SYNTAX or QUASISYNTAX form > can do likewise. Since pairs keep their identity during expansion, > location information for every node (and identifier leaf) can always be > looked up in the hash table at any stage of the expansion. [Sorry for replying out of order.] You mean in a global hash table? That's a hack around the lack of a field in the syntax objects. To make it work efficiently, you'd have to bring weakness in---a lot of machinery to duplicate functionality that would trivially work if syntax objects were abstract and thus extensible. -- Cheers =8-} Mike Friede, Völkerverständigung und überhaupt blabla