CODEWITHSUNDEEP
xmldtdfile-conversionrelaxng
David Eyk
David Eyk

Reputation: 12571

Generating a DTD from a multi-file RelaxNG schema

I have a RelaxNG schema that's broken into several .rnc files. I would like to be able to convert them into a DTD, but trang complains about my use of the external directive:

$ trang schema/text.rnc schema/text.dtd
[...]/schema/text.rnc:3:6: error: sorry, "externalRef" is not supported
[...]/schema/text.rnc:4:9: error: sorry, "externalRef" is not supported
[...]/grcxml/schema/text.rnc:6:15: error: sorry, "externalRef" is not supported
[...]/schema/text.rnc:3:6: error: sorry, "externalRef" is not supported
Exception in thread "main" java.lang.NullPointerException
        at com.thaiopensource.relaxng.output.dtd.ContentType.ref(ContentType.java:138)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitRef(Analysis.java:232)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitRef(Analysis.java:78)
        at com.thaiopensource.relaxng.edit.RefPattern.accept(RefPattern.java:9)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.analyzeContentType(Analysis.java:336)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitGroup(Analysis.java:216)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitGroup(Analysis.java:78)
        at com.thaiopensource.relaxng.edit.GroupPattern.accept(GroupPattern.java:5)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.analyzeContentType(Analysis.java:336)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitElement(Analysis.java:118)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitElement(Analysis.java:78)
        at com.thaiopensource.relaxng.edit.ElementPattern.accept(ElementPattern.java:9)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.analyzeContentType(Analysis.java:336)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitRef(Analysis.java:232)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitRef(Analysis.java:78)
        at com.thaiopensource.relaxng.edit.RefPattern.accept(RefPattern.java:9)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.analyzeContentType(Analysis.java:336)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitDefine(Analysis.java:288)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitDefine(Analysis.java:78)
        at com.thaiopensource.relaxng.edit.DefineComponent.accept(DefineComponent.java:39)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitContainer(Analysis.java:278)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitGrammar(Analysis.java:258)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.visitGrammar(Analysis.java:78)
        at com.thaiopensource.relaxng.edit.GrammarPattern.accept(GrammarPattern.java:14)
        at com.thaiopensource.relaxng.output.dtd.Analysis$Analyzer.analyzeContentType(Analysis.java:336)
        at com.thaiopensource.relaxng.output.dtd.Analysis.<init>(Analysis.java:534)
        at com.thaiopensource.relaxng.output.dtd.DtdOutputFormat.output(DtdOutputFormat.java:22)
        at com.thaiopensource.relaxng.translate.Driver.run(Driver.java:144)
        at com.thaiopensource.relaxng.translate.Driver.main(Driver.java:44)

Trang's ability to stuff an expressive schema like RelaxNG into a dim-bulb DTD seems miraculous enough that this roadblock surprises me. external includes are so nice for sharing definitions across schemata, I would hate to lose them. What would be the best way then to make this possible?

Upvotes: 1

Views: 359

Answers (2)

Louis
Louis

Reputation: 151491

If you don't care that the DTD won't replicate the division into files of the source, you could use jing first:

$ jing -s source.rng > intermediate.rng
$ trang intermediate.rng final.dtd

The first step will combine everything into one file. The second will convert.

Upvotes: 3

Rintze Zelle
Rintze Zelle

Reputation: 1744

I think you can use Trang to convert the .rnc compact schema to .rng, which should incorporate the external schemas into the main schema. Once you have a single .rng file, you might be able to convert that to a DTD.

See also https://code.google.com/p/jing-trang/issues/detail?id=51 and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=264706 .

Upvotes: 1

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