Thomas Lord scripsit: > You miss my point. We have overwhelming empirical evidence > that in some situations it is useful for string-ref to be O(1) and > in other situations for it to be O(n). If an implementation is > to be Scheme, is its choice between those to be mandated by the > report?
No, it is not to be mandated by the report, and it isn't. BTW, it occurred to me that a representation-switching implementation of strings can switch representations atomically provided the pointer to the code units (8-bit, 16-bit, or 32-bit) contains some tag bits indicating which one it is. When a string mutator detects that it needs to convert the representation, it builds up a new representation in freshly allocated memory, constructs the specially tagged pointer to it, and atomically swaps in the new pointer for the old. No locks. -- Mark Twain on Cecil Rhodes: John Cowan I admire him, I freely admit it, http://www.ccil.org/~cowan and when his time comes I shall [EMAIL PROTECTED] buy a piece of the rope for a keepsake. _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
