- From: Pat Hayes <phayes@ihmc.us>
- Date: Fri, 20 Jul 2012 13:22:25 -0500
- To: Andy Seaborne <andy.seaborne@epimorphics.com>
- Cc: public-rdf-dawg-comments@w3.org
On Jul 20, 2012, at 12:24 PM, Andy Seaborne wrote: > David, > > Surely the responsibility for the datatype values resides with the datatype? +1 Pat > > The rules for handling xsd decimals are entirely derived from XSD which already has rules for this situation. > > An RDF literal is a lexical form and a datatype; value translation is a matter for the datatype definition. > > If the lexical form is "0.049508196721311475409836" then the literal is "0.049508196721311475409836"^^xsd:literal. > > xsd:double and xsd:float are completely defined by XSD. > > xsd:decimal, being infinite, has a minimal requirement of expressibility with 16 digits in XSD 1.1, which was 18 in XSD 1.0 [1,2] > > Andy > > [1] http://www.w3.org/TR/xmlschema-2/#decimal > [2] http://www.w3.org/TR/xmlschema11-2/#partial-implementation > > On 20/07/12 16:19, David Booth wrote: >> It is currently difficult to compare the results of two different SPARQL >> servers when xsd:decimal, xsd:float or xsd:double are used, because >> there does not seem to be any standard way to control the number of >> decimal places that are serialized. For example, if the decimal >> 0.049508196721311475409836 is computed, one server may serialize this as >> >> "0.0495081967"^^xsd:decimal >> >> and another may serialize it as >> >> "0.050"^^xsd:decimal >> >> One might (erroneously) attempt to round both of the serialized values >> to one decimal place in order to compare them, but if they have already >> been rounded once before serialization (as above) then this won't work, >> because 0.050 rounds to 0.1, while 0.0495081967 rounds to 0.0. >> >> I think the SPARQL standard should provide some "SHOULD" guidance, such >> as specifying that a SPARLQ server SHOULD (by default) serialize a >> specified number of decimal places (perhaps all available), and MAY >> provide a standard means of controlling the number of decimal places >> that are serialized. >> >> If it is too late in the WG process to consider this for SPARQL 1.1 (and >> I assume it is) then please add this to the wish list for the next >> version. >> >> Thanks! >> > > > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Friday, 20 July 2012 18:23:01 UTC