I am posting this as an individual member of the Scheme community. I am not speaking for the R6RS editors, and this message should not be confused with the editors' eventual formal response.
Shiro Kawai wrote: > Sorry for my ignorance, but is there an important algorithm > that requires string-set!, even if you have both (a) means > to construct strings sequentially, like string ports, and > (b) means to create a vector of characters then convert it > to a string efficiently, like vector->string? Probably. I apologize for my ignorance also. What I do know is that, if the vector operations are O(1), then any O(f(N)) and Omega(N) time and space algorithm that uses string-set! can be replaced by an O(f(N)) and Omega(N) algorithm that doesn't use string-set!. You just convert your string to a vector at the beginning of the algorithm and convert back at the end. > If there are such algorithms, then again, which is important, > O(1) string-set! or O(1) substring (assuming that string > positions are given in a way to guarantee O(1) access), > under existence of preemptive threads? Important to whom? That's why this stuff is so controversial: We don't even have an objective objective function. > (It is highly likely that I don't have enough brain; We share that problem. > can we have both?) Silly answer: Yes, provided you're willing to abandon O(1) string-ref. Serious answer: I don't know. Probably not. Will _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
