Dear LyX developers, recent discussion about failing tests with the linguistics.module led to the suggestion:
Drop support for XeTeX + TeX fonts + inputenc utf8. Pro *There is no known case where this combination is required or helpfull.* LyX follows LaTeX in ceasing to officially support this combination. Users will not be confused by failing export. LyX developer resources will not be drained by dealing with confused users and failing tests. For power users with special needs, XeTeX + TeX fonts is still available after setting the input encoding to "ascii" or "utf8-plain". Con The combination XeTeX + TeX fonts is disabled also for documents where it does not currently lead to errors. (Is there any scenario where this would be a drawback?) Rationale: XeTeX is typically used with Unicode "non-TeX" fonts but can also be used with 8-bit TeX fonts. In LyX, the "View other formats > PDF (XeTeX)" toolbar button and the "Document>View>Other_Formats>PDF (XeTeX) menu entry work also for document with the "use non-TeX fonts" setting un-checked. However, XeTeX + TeX fonts is error prone: * You need "inputenc" to decode utf8 input. Otherwise non-ASCII characters may result in wrong output, missing characters, or compilation errors. (See https://www.lyx.org/trac/ticket/9740 for details.) However, "inputenc.sty" stopped working with XeTeX some years ago. Therefore, the fix for #9740 forced ASCII as input encoding for the combination XeTeX+TeX fonts. * Unfortunately, the ASCII input encoding leads to other problems. (See https://www.lyx.org/trac/ticket/10600 for details.) The fix for #10600 tricks "inputenc" to work with XeTeX. * Still, there are also other packages that fail with XeTeX + TeX fonts. Since TL18, this includes "expl3.sty" (by the LaTeX team) that is required by many other packages, some of them auto-loaded by LyX. Conclusion: XeTeX + TeX fonts works in some cases but is not officially supported by LaTeX. Maintaining support in LyX will need continuous effort in testing and working around problems. Günter
