On Mon, Jun 29, 2009 at 3:09 PM, Paolo Bonzini <paolo.bonzini at gmail.com>wrote:

> On 06/29/2009 11:08 PM, Eliot Miranda wrote:
>
>>
>> On reading this my first question us "what should at: do?".  Have you
>> thought this through?  Does at: have to search for TAG marks and skip
>> over them, or is the problem punted up to the client?
>>
>
> Tags are zero-width Unicode characters just like the byte-order mark
> U+FEFF.  Note that the tag uses a completely different set of characters
> than the normal Latin alphabet.  Similar to how in UTF-8/UTF-16 it is
> possible to find in O(1) time the beginning of a character, in this RFC it
> is always clear if a character is part of a tag or not.


But being able to find the start of a character in O(1) doesn't tell you how
many characters there are between a given address within the string
and its start address, and it doesn't tell you what the address of a
character at a given index in the string is.  So if the TAG representation
is the internal representation (which I think is implied by using this as a
means of carrying language information around with the character data) then
this representation implies O(N) at:, which means that it'll only be
suitable as an exchange representation (and expensive to encode/decode
to/from) or it needs an additional index structure, or...?



>
> Paolo
>
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