All makes sense. I've created a handful a bugs in the OpenDFDL repo to track these issues.
On 7/7/20 8:39 AM, Beckerle, Mike wrote: > I suggest adding an Issue/ticket to the OpenDFDL github for this. > > There are a few enhancements to this thing that would be helpful. > > As is, it only requires Saxon-PE, which is affordable for most usages. > > Another feature would be a cache of the compiled DFDL schema so that the > penalty > to compile it isn't being paid every time you run the XSLT. (Something many > usages of Daffodil need - probably should be a feature supplied in a Daffodil > library so that it's not being reinvented.) Daffodil compilation times are > acceptable now for long-running processes, but not for quick start/stop > things > as XSLT commonly is. > > We should look into whether Java's built in XSLT could be used to do this > also. > > Roger suggests you just need XSLT 2.0, and maybe Java's built in XSLT is 2.0 > ? I > know it is not XSLT 3.0. But I wasn't able to quickly determine if it is > stuck > at version 1.0 or has been updated to 2.0. > > I am unclear if or how Java's XSLT supports extension functions however. But > I > suspect it does. The trick is the parse-xml() function or other way to > construct > the XML again that the XSLT operates on. > > > > > -------------------------------------------------------------------------------- > *From:* Steve Lawrence <slawre...@apache.org> > *Sent:* Tuesday, July 7, 2020 8:15 AM > *To:* users@daffodil.apache.org <users@daffodil.apache.org> > *Subject:* Re: Here's how XSLT programs can use DFDL/Daffodil > Great! Thanks Mike! > > The only downside to this that I see is that it requires Saxon-EE to use > reflexive extension functions, which takes a little bit of effort to get. > > I'm wondering if it would be worth updating this to use Saxon's newer > integrated extension functions [1] rather than the reflexive extension > functions? It looks like it requires a bit more code to setup the > extension function and register with Saxon, but it is supported in > Saxon-HE which is much easier to get via maven. And I'd like to > integrate this into a Daffodil regression suite, which would be easier > if all dependencies were in maven. > > I can take a look at making this update if this seems reasonable. > > - Steve > > [1] > http://www.saxonica.com/documentation/#!extensibility/integratedfunctions > > > On 7/6/20 7:04 PM, Beckerle, Mike wrote: >> I captured Roger's example from this email and put in on github here with a >> test. >> >> https://github.com/OpenDFDL/examples/tree/master/xslt-csv >> >> This isn't part of Daffodil, but it's an interesting example combining XSLT >> with >> Daffodil. >> >> -------------------------------------------------------------------------------- >> *From:* Roger L Costello <coste...@mitre.org> >> *Sent:* Tuesday, June 2, 2020 12:10 PM >> *To:* users@daffodil.apache.org <users@daffodil.apache.org> >> *Subject:* Here's how XSLT programs can use DFDL/Daffodil >> >> Hi Folks, >> >> Below is an XSLT program that processes XML-formatted CSV. The XSLT program >> calls an external Java program, passing it the name of a DFDL file >> (csv.dfdl.xsd) and the name of a CSV file (csv.txt). The Java program calls >> Daffodil which produces XML-formatted CSV. The Java program returns the XML >> as a >> string. The XSLT program uses the parse-xml() function to convert the string >> to >> XML. >> >> <xsl:stylesheetxmlns:xsl="http://www.w3.org/1999/XSL/Transform"; >> xmlns:xs="http://www.w3.org/2001/XMLSchema"; >> xmlns:dfdl="java:runDaffodil" >> version="3.0"> >> >> <xsl:variablename="dfdl"select="'csv.dfdl.xsd'"/> >> <xsl:variablename="input"select="'csv.txt'"/> >> >> <xsl:templatematch="/"> >> <!-- Convert the CSV text file to XML using DFDL --> >> <xsl:variablename="csv-string"select="/dfdl:dfdlParse/(*$dfdl*,*$input*)"as="xs:string"/> >> <xsl:variablename="csv-xml"select="/parse-xml/(*$csv-string*)"as="document-node()"/> >> <!-- Process the XML-formatted CSV here --> >> <xsl:variablename="numRecords"select="/count/(*$csv-xml*//*record*)"as="xs:integer"/> >> <!-- Output the number of records in the CSV file --> >> <xsl:sequenceselect="*$numRecords*"/> >> <!-- Output the model (field 3) and year (field 1) of each Chevy auto --> >> <xsl:for-eachselect="*$csv-xml*//*record*[*field*[2] eq'Chevy']"> >> <xsl:sequenceselect="(*field*[3]//data/(),' ',*field*[1]//data/())"/> >> </xsl:for-each> >> </xsl:template> >> </xsl:stylesheet> >> >> The XSLT program uses XSLT version 3.0. You can use any version except 1.0 >> (the >> parse-xml() function is not present in XSLT 1.0). I used Saxon as the XSLT >> processor. >> >> The Java program calls Daffodil which parses the CSV file using the DFDL >> schema. >> Here is the Java program: >> >> *import*java.io.IOException; >> *import*java.net.URISyntaxException; >> *import*java.net.URL; >> >> *import*org.jdom2.Document; >> *import*org.jdom2.output.XMLOutputter; >> >> *import*org.apache.daffodil.japi.Compiler; >> *import*org.apache.daffodil.japi.Daffodil; >> *import*org.apache.daffodil.japi.DataProcessor; >> *import*org.apache.daffodil.japi.Diagnostic; >> *import*org.apache.daffodil.japi.ParseResult; >> *import*org.apache.daffodil.japi.ProcessorFactory; >> *import*org.apache.daffodil.japi.infoset.JDOMInfosetOutputter; >> *import*org.apache.daffodil.japi.io.InputSourceDataInputStream; >> >> *public**class*runDaffodil { >> >> *public**static*String dfdlParse(String dfdl,String >> input)*throws*IOException,URISyntaxException { >> >> URL dfdlURL =runDaffodil.*class*.getResource(dfdl); >> URL inputURL =runDaffodil.*class*.getResource(input); >> >> // >> // First, compile the DFDL Schema >> // >> Compiler c =Daffodil.compiler(); >> ProcessorFactory pf =c.compileSource(dfdlURL.toURI()); >> DataProcessor dp =pf.onPath("/"); >> >> // >> // Parse - parse data to XML >> // >> java.io.InputStream is =inputURL.openStream(); >> InputSourceDataInputStream dis =*new*InputSourceDataInputStream(is); >> >> // >> // Setup JDOM outputter >> // >> JDOMInfosetOutputter outputter =*new*JDOMInfosetOutputter(); >> >> // >> // Do the parse >> // >> ParseResult res =dp.parse(dis,outputter); >> >> // >> // Return the XML as a string >> // >> Document doc =outputter.getResult(); >> *return**new*XMLOutputter().outputString(doc); >> } >> } >> >
