William D Clinger wrote: >> 2. There are no explicit provisions for a limited repertoire of >> characters, where resources are limited. It looks like all characters >> must be supported. >> > > Correct. That is one of the many absolute requirements > of the R6RS that should not have been. >
Moreover, R6 forbids the addition of characters which are not Unicode scalar values. You may not limit the character set, and you may not extend it, at least in the core language. If you want to find a "design motif" that explains R6's char and string types, I think you need look no further than to see that they are more or less a direct transliteration of the way scalar values and locale-independent string processing are defined in the Unicode standard. All of the higher-level constructs in Unicode (e.g., compound characters, locale support) are founded (aka "defined in terms of") the scalar value model -- so it is a straight exercise in transliteration to make R6 libraries of those, given the core of this sort. It is as if R6 were designed, in part, to be a domain-specific language for the purpose of playing with a "pure" implementation of the Unicode character model. (This is, of course, a regression from lisp tradition and Scheme tradition in which the character type was extensible and far more abstract.) -t _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
