[LyX/master] Update comments after solving #9740.

[Günter Milde]

commit 8021c0b0dcf588527eeb183ca52e4900ffbf7527
Author: Günter Milde <mi...@lyx.org>
Date:   Fri Nov 13 13:59:17 2015 +0100

    Update comments after solving #9740.

diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index f2eae77..d24342c 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -1651,7 +1651,7 @@ bool Buffer::makeLaTeXFile(FileName const & fname,
        OutputParams runparams = runparams_in;
 
        // XeTeX with TeX fonts is only safe with ASCII encoding,
-       // See #9740 and FIXME in BufferParams::encoding()
+       // but the "flavor" is not known in BufferParams::encoding().
        if (!params().useNonTeXFonts && (runparams.flavor == 
OutputParams::XETEX))
                runparams.encoding = encodings.fromLyXName("ascii");
 
@@ -1738,12 +1738,12 @@ void Buffer::writeLaTeXSource(otexstream & os,
        OutputParams runparams = runparams_in;
 
        // XeTeX with TeX fonts is only safe with ASCII encoding,
-       // See #9740 and FIXME in BufferParams::encoding()
-       // FIXME: when only the current paragraph is shown, this is ignored and
-       //        characters encodable in the current encoding are not converted
-       //        to ASCII-representation.
+       // but the "flavor" is not known in BufferParams::encoding().
        if (!params().useNonTeXFonts && (runparams.flavor == 
OutputParams::XETEX))
                runparams.encoding = encodings.fromLyXName("ascii");
+       // FIXME: when only the current paragraph is shown, this is ignored
+       //        (or not reached) and characters encodable in the current
+       //        encoding are not converted to ASCII-representation.
 
        // If we are compiling a file standalone, even if this is the
        // child of some other buffer, let's cut the link here, so the
diff --git a/src/BufferParams.cpp b/src/BufferParams.cpp
index fa2f97b..3af1427 100644
--- a/src/BufferParams.cpp
+++ b/src/BufferParams.cpp
@@ -3141,14 +3141,13 @@ string const BufferParams::loadFonts(LaTeXFeatures & 
features) const
 
 Encoding const & BufferParams::encoding() const
 {
-       // FIXME: For export with XeTeX and TeX fonts,
-       //   this function returns the wrong value.
-       //   The combination of XeTeX and TeX-fonts requires ASCII (see #9740).
-       //   However, the flavor is no buffer parameter but only known once 
export started.
-       //   Currently, we set runparams.encoding to ASCII in 
Buffer::makeLaTeXFile
-       //   (for export) and Buffer::writeLaTeXSource (for preview)
-       //   and prevent overwriting it with another encoding in 
Paragraph::latex
-       //   and at four places in output_latex.cpp.
+       // Main encoding for LaTeX output.
+       // 
+       // Exception: XeTeX with 8-bit TeX fonts requires ASCII (see #9740).
+       // As the "flavor" is only known once export started, this
+       // cannot be handled here. Instead, runparams.encoding is set
+       // to ASCII in Buffer::makeLaTeXFile (for export)
+       // and Buffer::writeLaTeXSource (for preview).
        if (useNonTeXFonts)
                return *(encodings.fromLyXName("utf8-plain"));
        if (inputenc == "auto" || inputenc == "default")
diff --git a/src/BufferParams.h b/src/BufferParams.h
index 6b2bb47..a0e0d45 100644
--- a/src/BufferParams.h
+++ b/src/BufferParams.h
@@ -314,6 +314,8 @@ public:
        std::string inputenc;
        /// The main encoding used by this buffer for LaTeX output.
        /// Individual pieces of text can use different encodings.
+       /// Output for XeTeX with 8-bit TeX fonts uses ASCII (set at runtime)
+       /// instead of the value returned by this function.
        Encoding const & encoding() const;
        ///
        std::string origin;