On Feb 24, 2009, at 1:40 PM, Thomas Lord wrote: > If it were the case that Guillermo's ESTA and > your ESTA were distinct symbols, and if each of > those symbols contained additional information, > then (perhaps) two distinct downcasing rules > could be applied. > > What "additional information" should a symbol > contain? Well, perhaps a global namespace identifier > such as a URI. For example, when you write > "ESTA" this might be understood (from lexical context) > to mean "scheme-id://alan-watsons-world/ESTA" > whereas Guillermo's means "scheme-id://guillermos-world/ESTA". >
This is a slippery road toward symbol property lists. > Of course, those specific URIs would not necessarily > be good choices. They are just there to illustrate the > concept. > > Elsewhere could be declared the conversion rules > for the two "worlds" - the two name-spaces. > > Done right, this would afford a third party to > combine your two programs in a controlled way. > Someone could write a single file containing > both versions of ESTA without ambiguity. > > There are other reasons to like the idea of "lifting" > symbol names in this way. It can contribute to modularity > in more ways than just having two case conversion > rules for ESTA. It also suggests a parsimonious representation > in Scheme for URI's and for XML's fully qualified element > names. This seems an excellent argument against CI symbols in the language when more than 7-bit ASCII character set is allowed. --andrew _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
