On Mon, 2 Apr 2018 22:02:41 +0100, Peter Flynn wrote: > On 01/04/18 22:10, Lawrence D'Oliveiro wrote: > >> The content for these is *not* “just strings”. > > But only a human can know that; it is probably documented somewhere > else. Fontconfig knows it too. > The DTD says the content is "parsed character data", which is > text with no further element markup; in effect "just strings", so > that's it as far as SGML or XML is concerned if you use a DTD alone. Precisely why a DTD is useless. > A W3C Schema can constrain character data content more finely, and > Schematron can apply additional validation rules. Is it better to replace the DTD with a “Schematron”, then? >> Given that it will accept files that are not valid Fontconfig >> configurations, the validation function seems useless. > > What is "it" in this context? Fontconfig? Or the DTD? Maybe the DTD > has been written incorrectly. But you have just admitted that there is no way to write the DTD correctly. > A DTD can only be used to test validity within the constraints of what > it has been told. If there are additional constraints which cannot be > expressed in XML Declaration Syntax (DTD-speak) then Fontconfig should > be using a different language like W3C Schema or RelaxNG. Or maybe it should simply continue using what it already uses, a language called C, which exactly accepts valid Fontconfig configs, no more and no less <https://cgit.freedesktop.org/fontconfig/tree/src/fcxml.c>. _______________________________________________ Fontconfig mailing list Fontconfig@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/fontconfig
