- From: Michael Kay <mike@saxonica.com>
- Date: Thu, 14 Mar 2013 08:59:32 +0000
- To: Adam Retter <adam@exist-db.org>
- CC: public-expath@w3.org

On 13/03/2013 17:20, Adam Retter wrote: > A second stream of consciousness: > > I feel very uneasy about representing octets using integers. So I ask > myself why? Is it history - i.e. eXist and Zorba (maybe others) > represent octets as octal strings and allow for the conversion of > octal to/from decimal with functions. Odd, I haven't seen octal used in anger for about 25 years, I thought it was completely obsolete. But then I guess I've managed to avoid writing in C. Every since the industry standardized on an 8-bit byte, hexadecimal has seemed much more natural. > > An octet is implicitly in Base 8 Eh? if it's anything, surely it's implicitly in base 2? > , so why would I then want to > manipulate it as thought it were Base 10 (but without converting it to > Base 10). This just doesnt make sense to me - > > If I understand correctly - > > bin:binary-to-octets(xs:hexBinary("FFFF")) would give me (255, 255) Seems natural to me. > > Rather if you want to go to base10 then > bin:binary-to-radix(xs:hexBinary("FFFF"), 10) could give me 65535. But there's nothing intrinsically decimal about the value 65535, other than the way it's being printed on the page. bin:binary-to-radix(xs:hexBinary("FFFF"), 17) would give you exactly the same integer - it only becomes base 17 when you convert the integer to a string to display it. > > > All of the bitwise operators seem to operate on xs:hexBinary Yes, I think it's a separate discussion whether bitwise operators on integers would be more useful. I think the main problem is that we don't have hex literals, so we can't say $x & xFF00, instead we have to say either (1) if we use hexBinary: bin:and($x, xs:hexBinary("FF00")) (2) if we use base64Binary: bin:and ($x, xs:base64Binary("/wA=")) (3) if we use integer: bin:and($x, 65280) None of these is nice, but the first seems to me the most readable. If we go with (and/or/not) working on integers, then perhaps we should also have functions bin:hex("FF00") => 65280 bin:octal("177400") => 65280 (since you're telling me that there are indeed people who still use octal...) Michael Kay Saxonica

Received on Thursday, 14 March 2013 08:59:55 UTC