]> git.lyx.org Git - lyx.git/blobdiff - src/output_latex.cpp
Correctly set language after intitle paragraphs
[lyx.git] / src / output_latex.cpp
index 4e637ee8056bad4385350191f39c4f3677c143a9..4124d2dd1c92fde9f5cf08cb62ca29808ed1277f 100644 (file)
@@ -12,6 +12,7 @@
 
 #include "output_latex.h"
 
+#include "BiblioInfo.h"
 #include "Buffer.h"
 #include "BufferParams.h"
 #include "Encoding.h"
@@ -63,7 +64,7 @@ enum OpenEncoding {
 struct OutputState
 {
        OutputState() : open_encoding_(none), cjk_inherited_(0),
-                       prev_env_language_(0), nest_level_(0)
+               prev_env_language_(nullptr), nest_level_(0)
        {
        }
        OpenEncoding open_encoding_;
@@ -191,7 +192,7 @@ static TeXEnvironmentData prepareEnvironment(Buffer const & buf,
                pit == paragraphs.begin() ? pit : prev(pit, 1);
 
        OutputState * state = getOutputState();
-       bool const use_prev_env_language = state->prev_env_language_ != 0
+       bool const use_prev_env_language = state->prev_env_language_ != nullptr
                        && priorpit->layout().isEnvironment()
                        && (priorpit->getDepth() > pit->getDepth()
                            || (priorpit->getDepth() == pit->getDepth()
@@ -304,8 +305,11 @@ static TeXEnvironmentData prepareEnvironment(Buffer const & buf,
 
        // in multilingual environments, the CJK tags have to be nested properly
        data.cjk_nested = false;
-       if (data.par_language->encoding()->package() == Encoding::CJK &&
-           state->open_encoding_ != CJK && pit->isMultiLingual(bparams)) {
+       if (!bparams.useNonTeXFonts
+           && (bparams.inputenc == "auto-legacy"
+                       || bparams.inputenc == "auto-legacy-plain")
+           && data.par_language->encoding()->package() == Encoding::CJK
+           && state->open_encoding_ != CJK && pit->isMultiLingual(bparams)) {
                if (prev_par_language->encoding()->package() == Encoding::CJK) {
                        os << "\\begin{CJK}{"
                           << from_ascii(data.par_language->encoding()->latexName())
@@ -675,8 +679,12 @@ void parStartCommand(Paragraph const & par, otexstream & os,
 {
        switch (style.latextype) {
        case LATEX_COMMAND:
-               if (par.needsCProtection(runparams.moving_arg))
+               if (par.needsCProtection(runparams.moving_arg)) {
+                       if (contains(runparams.active_chars, '^'))
+                               // cprotect relies on ^ being on catcode 7
+                               os << "\\begingroup\\catcode`\\^=7";
                        os << "\\cprotect";
+               }
                os << '\\' << from_ascii(style.latexname());
 
                // Command arguments
@@ -697,6 +705,11 @@ void parStartCommand(Paragraph const & par, otexstream & os,
                        os << " ";
                }
                break;
+       case LATEX_ENVIRONMENT:
+               if (runparams.for_search) {
+                       os << "\\latexenvironment{" << style.latexname() << "}{";
+               }
+               break;
        case LATEX_BIB_ENVIRONMENT:
                // ignore this, the inset will write itself
                break;
@@ -734,7 +747,7 @@ void TeXOnePar(Buffer const & buf,
 
        OutputParams runparams = runparams_in;
        runparams.isLastPar = (pit == pit_type(paragraphs.size() - 1));
-       // We reinitialze par begin and end to be on the safe side
+       // We reinitialize par begin and end to be on the safe side
        // with embedded inset as we don't know if they set those
        // value correctly.
        runparams.par_begin = 0;
@@ -754,7 +767,7 @@ void TeXOnePar(Buffer const & buf,
                Font const outerfont = text.outerFont(pit);
 
                // No newline before first paragraph in this lyxtext
-               if (pit > 0) {
+               if (pit > 0 && !text.inset().getLayout().parbreakIgnored()) {
                        os << '\n';
                        if (!text.inset().getLayout().parbreakIsNewline())
                                os << '\n';
@@ -765,13 +778,18 @@ void TeXOnePar(Buffer const & buf,
        }
 
        Paragraph const * nextpar = runparams.isLastPar
-               ? 0 : &paragraphs.at(pit + 1);
+               ? nullptr : &paragraphs.at(pit + 1);
 
-       bool const intitle_command = style.intitle && style.latextype == LATEX_COMMAND;
+       bool const intitle_command = style.intitle && style.isCommand();
 
        if (style.pass_thru) {
                Font const outerfont = text.outerFont(pit);
                parStartCommand(par, os, runparams, style);
+               if (style.isCommand() && style.needprotect)
+                       // Due to the moving argument, some fragile
+                       // commands (labels, index entries)
+                       // are output after this command (#2154)
+                       runparams.postpone_fragile_stuff = true;
                if (intitle_command)
                        os << '{';
 
@@ -780,8 +798,13 @@ void TeXOnePar(Buffer const & buf,
                // I did not create a parEndCommand for this minuscule
                // task because in the other user of parStartCommand
                // the code is different (JMarc)
-               if (style.isCommand())
-                       os << "}\n";
+               if (style.isCommand()) {
+                       os << "}";
+                       if (par.needsCProtection(runparams.moving_arg)
+                           && contains(runparams.active_chars, '^'))
+                               os << "\\endgroup";
+                       os << "\n";
+               }
                else
                        os << '\n';
                if (!style.parbreak_is_newline) {
@@ -800,16 +823,16 @@ void TeXOnePar(Buffer const & buf,
        // This paragraph's language
        Language const * const par_language = par.getParLanguage(bparams);
        Language const * const nextpar_language = nextpar ?
-               nextpar->getParLanguage(bparams) : 0;
+               nextpar->getParLanguage(bparams) : nullptr;
        // The document's language
        Language const * const doc_language = bparams.language;
        // The language that was in effect when the environment this paragraph is
        // inside of was opened
        Language const * const outer_language =
-               (runparams.local_font != 0) ?
+               (runparams.local_font != nullptr) ?
                        runparams.local_font->language() : doc_language;
 
-       Paragraph const * priorpar = (pit == 0) ? 0 : &paragraphs.at(pit - 1);
+       Paragraph const * priorpar = (pit == 0) ? nullptr : &paragraphs.at(pit - 1);
 
        // The previous language that was in effect is the language of the
        // previous paragraph, unless the previous paragraph is inside an
@@ -819,19 +842,36 @@ void TeXOnePar(Buffer const & buf,
        // Note further that we take the outer language also if the prior par
        // is PassThru, since in that case it has latex_language, and all secondary
        // languages have been closed (#10793).
-       bool const use_prev_env_language = state->prev_env_language_ != 0
+       bool const use_prev_env_language = state->prev_env_language_ != nullptr
                        && priorpar
                        && priorpar->layout().isEnvironment()
                        && (priorpar->getDepth() > par.getDepth()
                            || (priorpar->getDepth() == par.getDepth()
-                                   && priorpar->layout() != par.layout()));
+                               && priorpar->layout() != par.layout()));
+
+       // We need to ignore previous intitle commands since languages
+       // are switched locally there (# 11514)
+       // There might be paragraphs before the title, so we check this.
+       Paragraph * prior_nontitle_par = nullptr;
+       if (!intitle_command) {
+               pit_type ppit = pit;
+               while (ppit > 0) {
+                       --ppit;
+                       Paragraph const * tmppar = &paragraphs.at(ppit);
+                       if (tmppar->layout().intitle && tmppar->layout().isCommand())
+                               continue;
+                       prior_nontitle_par = const_cast<Paragraph*>(tmppar);
+                       break;
+               }
+       }
        Language const * const prev_language =
-               runparams_in.for_search ?
-                       languages.getLanguage("ignore")
-               :(priorpar && !priorpar->isPassThru())
-                       ? (use_prev_env_language ? state->prev_env_language_
-                                               : priorpar->getParLanguage(bparams))
-                       : outer_language;
+               runparams_in.for_search 
+                       ? languages.getLanguage("ignore")
+                       : (prior_nontitle_par && !prior_nontitle_par->isPassThru())
+                               ? (use_prev_env_language 
+                                       ? state->prev_env_language_
+                                       : prior_nontitle_par->getParLanguage(bparams))
+                               : outer_language;
 
        bool const use_polyglossia = runparams.use_polyglossia;
        string const par_lang = use_polyglossia ?
@@ -856,6 +896,11 @@ void TeXOnePar(Buffer const & buf,
        // (see #10849); thus open the command here.
        if (intitle_command) {
                parStartCommand(par, os, runparams, style);
+               if (style.isCommand() && style.needprotect)
+                       // Due to the moving argument, some fragile
+                       // commands (labels, index entries)
+                       // are output after this command (#2154)
+                       runparams.postpone_fragile_stuff = true;
                os << '{';
        }
 
@@ -865,7 +910,7 @@ void TeXOnePar(Buffer const & buf,
        // languages (see # 10111).
        bool const in_polyglossia_rtl_env =
                use_polyglossia
-               && runparams.local_font != 0
+               && runparams.local_font != nullptr
                && outer_language->rightToLeft()
                && !par_language->rightToLeft();
        bool const localswitch = runparams_in.for_search
@@ -921,7 +966,7 @@ void TeXOnePar(Buffer const & buf,
                            && par_language->lang() != "arabic_arabtex"
                            && outer_language->lang() != "arabic_arabtex"
                            // are we in an inset?
-                           && runparams.local_font != 0
+                           && runparams.local_font != nullptr
                            // is the inset within an \L or \R?
                            //
                            // FIXME: currently, we don't check this; this means that
@@ -948,8 +993,10 @@ void TeXOnePar(Buffer const & buf,
                                        os << "\\L{";
                        }
                        // With CJK, the CJK tag has to be closed first (see below)
-                       if ((runparams.encoding->package() != Encoding::CJK || runparams.for_search)
-                           && (par_lang != openLanguageName(state) || localswitch)
+                       if ((runparams.encoding->package() != Encoding::CJK
+                                || bparams.useNonTeXFonts
+                                || runparams.for_search)
+                           && (par_lang != openLanguageName(state) || localswitch || intitle_command)
                            && !par_lang.empty()) {
                                string bc = use_polyglossia ?
                                          getPolyglossiaBegin(lang_begin_command, par_lang,
@@ -964,11 +1011,12 @@ void TeXOnePar(Buffer const & buf,
                }
        }
 
-       // Switch file encoding if necessary; no need to do this for "default"
+       // Switch file encoding if necessary; no need to do this for "auto-legacy-plain"
        // encoding, since this only affects the position of the outputted
        // \inputencoding command; the encoding switch will occur when necessary
-       if (bparams.inputenc == "auto"
+       if (bparams.inputenc == "auto-legacy"
                && !runparams.isFullUnicode() // Xe/LuaTeX use one document-wide encoding  (see also switchEncoding())
+               && runparams.encoding->package() != Encoding::japanese
                && runparams.encoding->package() != Encoding::none) {
                // Look ahead for future encoding changes.
                // We try to output them at the beginning of the paragraph,
@@ -1014,12 +1062,7 @@ void TeXOnePar(Buffer const & buf,
                                if (runparams.encoding->package() == Encoding::CJK
                                    && par_lang != openLanguageName(state)
                                    && !par_lang.empty()) {
-                                       string bc = use_polyglossia ?
-                                                   getPolyglossiaBegin(lang_begin_command, par_lang,
-                                                                       par_language->polyglossiaOpts(),
-                                                                       localswitch)
-                                                   : subst(lang_begin_command, "$$lang", par_lang);
-                                       os << bc
+                                       os << subst(lang_begin_command, "$$lang", par_lang)
                                           << lang_command_termination;
                                        if (using_begin_end)
                                                pushLanguageName(par_lang, localswitch);
@@ -1031,6 +1074,8 @@ void TeXOnePar(Buffer const & buf,
        }
 
        runparams.moving_arg |= style.needprotect;
+       if (style.needmboxprotect)
+               ++runparams.inulemcmd;
        Encoding const * const prev_encoding = runparams.encoding;
 
        bool const useSetSpace = bparams.documentClass().provides("SetSpace");
@@ -1064,8 +1109,14 @@ void TeXOnePar(Buffer const & buf,
 
        // For InTitle commands, we already started the command before
        // the language switch
-       if (!intitle_command)
+       if (!intitle_command) {
                parStartCommand(par, os, runparams, style);
+               if (style.isCommand() && style.needprotect)
+                       // Due to the moving argument, some fragile
+                       // commands (labels, index entries)
+                       // are output after this command (#2154)
+                       runparams.postpone_fragile_stuff = true;
+       }
 
        Font const outerfont = text.outerFont(pit);
 
@@ -1085,6 +1136,15 @@ void TeXOnePar(Buffer const & buf,
                        os << '}';
                        if (!style.postcommandargs().empty())
                                latexArgInsets(par, os, runparams, style.postcommandargs(), "post:");
+                       if (!runparams.post_macro.empty()) {
+                               // Output the stored fragile commands (labels, indices etc.)
+                               // that need to be output after the command with moving argument.
+                               os << runparams.post_macro;
+                               runparams.post_macro.clear();
+                       }
+                       if (par.needsCProtection(runparams.moving_arg)
+                           && contains(runparams.active_chars, '^'))
+                               os << "\\endgroup";
                        if (runparams.encoding != prev_encoding) {
                                runparams.encoding = prev_encoding;
                                os << setEncoding(prev_encoding->iconvName());
@@ -1104,10 +1164,10 @@ void TeXOnePar(Buffer const & buf,
                            && nextpar->getDepth() < par.getDepth()))
                        close_lang_switch = using_begin_end;
                if (nextpar && par.params().depth() < nextpar->params().depth())
-                       pending_newline = true;
+                       pending_newline = !text.inset().getLayout().parbreakIgnored();
                break;
        case LATEX_ENVIRONMENT: {
-               // if its the last paragraph of the current environment
+               // if it's the last paragraph of the current environment
                // skip it otherwise fall through
                if (nextpar
                    && ((nextpar->layout() != par.layout()
@@ -1123,7 +1183,7 @@ void TeXOnePar(Buffer const & buf,
        default:
                // we don't need it for the last paragraph and in InTitle commands!!!
                if (nextpar && !intitle_command)
-                       pending_newline = true;
+                       pending_newline = !text.inset().getLayout().parbreakIgnored();
        }
 
        // InTitle commands use switches (not environments) for space settings
@@ -1152,7 +1212,7 @@ void TeXOnePar(Buffer const & buf,
                && (par_language->lang() != "arabic_arabtex"
                    && outer_language->lang() != "arabic_arabtex")
                // have we opened an \L or \R environment?
-               && runparams.local_font != 0
+               && runparams.local_font != nullptr
                && runparams.local_font->isRightToLeft() != par_language->rightToLeft()
                // are we about to close the language?
                &&((nextpar && par_lang != nextpar_lang)
@@ -1161,7 +1221,7 @@ void TeXOnePar(Buffer const & buf,
        if (localswitch_needed
            || (intitle_command && using_begin_end)
            || closing_rtl_ltr_environment
-           || ((runparams.isLastPar || close_lang_switch)
+           || (((runparams.isLastPar && !runparams.inbranch) || close_lang_switch)
                && (par_lang != outer_lang || (using_begin_end
                                                && style.isEnvironment()
                                                && par_lang != nextpar_lang)))) {
@@ -1173,7 +1233,9 @@ void TeXOnePar(Buffer const & buf,
                        os << '\n';
 
                // when the paragraph uses CJK, the language has to be closed earlier
-               if ((font.language()->encoding()->package() != Encoding::CJK) || runparams_in.for_search) {
+               if ((font.language()->encoding()->package() != Encoding::CJK)
+                       || bparams.useNonTeXFonts
+                       || runparams_in.for_search) {
                        if (lang_end_command.empty()) {
                                // If this is a child, we should restore the
                                // master language after the last paragraph.
@@ -1192,7 +1254,8 @@ void TeXOnePar(Buffer const & buf,
                                                                        localswitch)
                                                  : subst(lang_begin_command, "$$lang", current_lang);
                                        os << bc;
-                                       pending_newline = !localswitch;
+                                       pending_newline = !localswitch
+                                                       && !text.inset().getLayout().parbreakIgnored();
                                        unskip_newline = !localswitch;
                                        if (using_begin_end)
                                                pushLanguageName(current_lang, localswitch);
@@ -1222,7 +1285,8 @@ void TeXOnePar(Buffer const & buf,
                                                lang_end_command,
                                                "$$lang",
                                                par_lang));
-                                       pending_newline = !localswitch;
+                                       pending_newline = !localswitch
+                                                       && !text.inset().getLayout().parbreakIgnored();
                                        unskip_newline = !localswitch;
                                        if (using_begin_end)
                                                popLanguageName();
@@ -1235,14 +1299,21 @@ void TeXOnePar(Buffer const & buf,
 
        // InTitle commands need to be closed after the language has been closed.
        if (intitle_command) {
-               if (is_command) {
-                       os << '}';
-                       if (!style.postcommandargs().empty())
-                               latexArgInsets(par, os, runparams, style.postcommandargs(), "post:");
-                       if (runparams.encoding != prev_encoding) {
-                               runparams.encoding = prev_encoding;
-                               os << setEncoding(prev_encoding->iconvName());
-                       }
+               os << '}';
+               if (!style.postcommandargs().empty())
+                       latexArgInsets(par, os, runparams, style.postcommandargs(), "post:");
+               if (!runparams.post_macro.empty()) {
+                       // Output the stored fragile commands (labels, indices etc.)
+                       // that need to be output after the command with moving argument.
+                       os << runparams.post_macro;
+                       runparams.post_macro.clear();
+               }
+               if (par.needsCProtection(runparams.moving_arg)
+                   && contains(runparams.active_chars, '^'))
+                       os << "\\endgroup";
+               if (runparams.encoding != prev_encoding) {
+                       runparams.encoding = prev_encoding;
+                       os << setEncoding(prev_encoding->iconvName());
                }
        }
 
@@ -1259,11 +1330,11 @@ void TeXOnePar(Buffer const & buf,
 
        // if this is a CJK-paragraph and the next isn't, close CJK
        // also if the next paragraph is a multilingual environment (because of nesting)
-       if (nextpar
-               && (state->open_encoding_ == CJK && bparams.encoding().iconvName() != "UTF-8"
-                       && bparams.encoding().package() != Encoding::CJK )
+       if (nextpar && state->open_encoding_ == CJK
+               && bparams.encoding().iconvName() != "UTF-8"
+               && bparams.encoding().package() != Encoding::CJK
                && (nextpar_language->encoding()->package() != Encoding::CJK
-                  || (nextpar->layout().isEnvironment() && nextpar->isMultiLingual(bparams)))
+                       || (nextpar->layout().isEnvironment() && nextpar->isMultiLingual(bparams)))
                // inbetween environments, CJK has to be closed later (nesting!)
                && (!style.isEnvironment() || !nextpar->layout().isEnvironment())) {
                os << "\\end{CJK}\n";
@@ -1290,6 +1361,12 @@ void TeXOnePar(Buffer const & buf,
                                break;
                        }
                        case inputenc: {
+                               // FIXME: If we are in an inset and the switch happened outside this inset,
+                               // do not switch back at the end of the inset (bug #8479)
+                               // The following attempt does not help with listings-caption in a CJK document:
+                               // if (runparams_in.local_font != 0
+                               //    && runparams_in.encoding == runparams_in.local_font->language()->encoding())
+                               //      break;
                                os << "\\egroup";
                                state->open_encoding_ = none;
                                break;
@@ -1301,13 +1378,13 @@ void TeXOnePar(Buffer const & buf,
                }
        }
 
-       // If this is the last paragraph, and a local_font was set upon entering
-       // the inset, and we're using "auto" or "default" encoding, and not
-       // compiling with XeTeX or LuaTeX, the encoding
-       // should be set back to that local_font's encoding.
-       if (runparams.isLastPar && runparams_in.local_font != 0
+       // Information about local language is stored as a font feature.
+       // If this is the last paragraph of the inset and a local_font was set upon entering
+       // and we are mixing encodings ("auto-legacy" or "auto-legacy-plain" and no XeTeX or LuaTeX),
+       // ensure the encoding is set back to the default encoding of the local language.
+       if (runparams.isLastPar && runparams_in.local_font != nullptr
            && runparams_in.encoding != runparams_in.local_font->language()->encoding()
-           && (bparams.inputenc == "auto" || bparams.inputenc == "default")
+           && (bparams.inputenc == "auto-legacy" || bparams.inputenc == "auto-legacy-plain")
                && !runparams.isFullUnicode()
           ) {
                runparams_in.encoding = runparams_in.local_font->language()->encoding();
@@ -1317,14 +1394,18 @@ void TeXOnePar(Buffer const & buf,
        else
                runparams_in.encoding = runparams.encoding;
 
+       // Also pass the post_macros upstream
+       runparams_in.post_macro = runparams.post_macro;
+
 
        // we don't need a newline for the last paragraph!!!
        // Note from JMarc: we will re-add a \n explicitly in
        // TeXEnvironment, because it is needed in this case
        if (nextpar && !os.afterParbreak() && !last_was_separator) {
-               // Make sure to start a new line
-               os << breakln;
                Layout const & next_layout = nextpar->layout();
+               if (!text.inset().getLayout().parbreakIgnored())
+                       // Make sure to start a new line
+                       os << breakln;
                // A newline '\n' is always output before a command,
                // so avoid doubling it.
                if (!next_layout.isCommand()) {
@@ -1348,22 +1429,23 @@ void TeXOnePar(Buffer const & buf,
                        if ((style == next_layout
                             && !style.parbreak_is_newline
                             && !text.inset().getLayout().parbreakIsNewline()
+                            && !text.inset().getLayout().parbreakIgnored()
                             && style.latextype != LATEX_ITEM_ENVIRONMENT
                             && style.latextype != LATEX_LIST_ENVIRONMENT
-                            && style.align == par.getAlign()
+                            && style.align == par.getAlign(bparams)
                             && nextpar->getDepth() == par.getDepth()
-                            && nextpar->getAlign() == par.getAlign())
+                            && nextpar->getAlign(bparams) == par.getAlign(bparams))
                            || (!next_layout.isEnvironment()
                                && nextpar->getDepth() > par.getDepth()
-                               && nextpar->getAlign() == par.getAlign())
+                               && nextpar->getAlign(bparams) == next_layout.align)
                            || (!style.isEnvironment()
                                && next_layout.latextype == LATEX_ENVIRONMENT
                                && nextpar->getDepth() < par.getDepth())
                            || (style.isCommand()
                                && !next_layout.isEnvironment()
-                               && style.align == par.getAlign()
-                               && next_layout.align == nextpar->getAlign())
-                           || (style.align != par.getAlign()
+                               && style.align == par.getAlign(bparams)
+                               && next_layout.align == nextpar->getAlign(bparams))
+                           || (style.align != par.getAlign(bparams)
                                && tclass.isDefaultLayout(next_layout))) {
                                os << '\n';
                        }
@@ -1397,7 +1479,8 @@ void latexParagraphs(Buffer const & buf,
 
        if (multibib_child && mparams.useBiblatex())
                os << "\\newrefsection";
-       else if (multibib_child && mparams.useBibtopic()) {
+       else if (multibib_child && mparams.useBibtopic()
+                && !buf.masterBibInfo().empty()) {
                os << "\\begin{btUnit}\n";
                runparams.openbtUnit = true;
        }
@@ -1410,13 +1493,11 @@ void latexParagraphs(Buffer const & buf,
        if (maintext && !is_child && !bparams.useNonTeXFonts
            && (bparams.encoding().package() == Encoding::CJK
                        || (bparams.encoding().name() == "utf8"
-                               && bparams.language->encoding()->package() == Encoding::CJK)
-                               //  FIXME: should test if any language requires CJK
-                               //  && LaTeXFeatures::mustProvide("CJK"))
-                               // error: cannot call member function ‘bool lyx::LaTeXFeatures::mustProvide(const string&) const’ without object 
-                  )) {
+                               && runparams.use_CJK))
+          ) {
                docstring const cjkenc = bparams.encoding().iconvName() == "UTF-8"
-                                                                ? from_ascii("UTF8") : from_ascii(bparams.encoding().latexName());
+                                                                ? from_ascii("UTF8")
+                                                                : from_ascii(bparams.encoding().latexName());
                os << "\\begin{CJK}{" << cjkenc
                   << "}{" << from_ascii(bparams.fonts_cjk) << "}%\n";
                state->open_encoding_ = CJK;
@@ -1510,7 +1591,8 @@ void latexParagraphs(Buffer const & buf,
                    && layout.latexname() == bparams.multibib) {
                        if (runparams.openbtUnit)
                                os << "\\end{btUnit}\n";
-                       if (!bparams.useBiblatex()) {
+                       if (!bparams.useBiblatex()
+                           && !buf.masterBibInfo().empty()) {
                                os << '\n' << "\\begin{btUnit}\n";
                                runparams.openbtUnit = true;
                        }
@@ -1529,6 +1611,7 @@ void latexParagraphs(Buffer const & buf,
                finishEnvironment(os, runparams, data);
        }
 
+       // FIXME: uncomment the content or remove this block
        if (pit == runparams.par_end) {
                        // Make sure that the last paragraph is
                        // correctly terminated (because TeXOnePar does
@@ -1552,8 +1635,10 @@ void latexParagraphs(Buffer const & buf,
 
        // if "auto end" is switched off, explicitly close the language at the end
        // but only if the last par is in a babel or polyglossia language
+       Language const * const lastpar_language =
+                       paragraphs.at(lastpit).getParLanguage(bparams);
        if (maintext && !lyxrc.language_auto_end && !mainlang.empty() &&
-               paragraphs.at(lastpit).getParLanguage(bparams)->encoding()->package() != Encoding::CJK) {
+               lastpar_language->encoding()->package() != Encoding::CJK) {
                os << from_utf8(subst(lang_end_command,
                                        "$$lang",
                                        mainlang))
@@ -1569,14 +1654,29 @@ void latexParagraphs(Buffer const & buf,
                state->open_encoding_ = none;
        }
        // Likewise for polyglossia or when using begin/end commands
+       // or at the very end of an active branch inset with a language switch
+       Language const * const outer_language = (runparams.local_font != nullptr)
+                       ? runparams.local_font->language() : bparams.language;
+       string const & prev_lang = runparams.use_polyglossia
+                       ? getPolyglossiaEnvName(outer_language)
+                       : outer_language->babel();
+       string const lastpar_lang = runparams.use_polyglossia ?
+               getPolyglossiaEnvName(lastpar_language): lastpar_language->babel();
        string const & cur_lang = openLanguageName(state);
-       if (maintext && !is_child && !cur_lang.empty()) {
+       if (((runparams.inbranch && langOpenedAtThisLevel(state) && prev_lang != cur_lang)
+            || (maintext && !is_child)) && !cur_lang.empty()) {
                os << from_utf8(subst(lang_end_command,
                                        "$$lang",
                                        cur_lang))
                   << '\n';
                if (using_begin_end)
                        popLanguageName();
+       } else if (runparams.inbranch && !using_begin_end
+                  && prev_lang != lastpar_lang && !lastpar_lang.empty()) {
+               // with !using_begin_end, cur_lang is empty, so we need to
+               // compare against the paragraph language (and we are in the
+               // last paragraph at this point)
+               os << subst(lang_begin_command, "$$lang", prev_lang) << '\n';
        }
 
        // reset inherited encoding
@@ -1592,51 +1692,44 @@ void latexParagraphs(Buffer const & buf,
        }
 }
 
-
+// Switch the input encoding for some part(s) of the document.
 pair<bool, int> switchEncoding(odocstream & os, BufferParams const & bparams,
                   OutputParams const & runparams, Encoding const & newEnc,
                   bool force, bool noswitchmacro)
 {
-       // XeTeX/LuaTeX use only one encoding per document:
-       // * with useNonTeXFonts: "utf8plain",
-       // * with XeTeX and TeX fonts: "ascii" (inputenc fails),
-       // * with LuaTeX and TeX fonts: only one encoding accepted by luainputenc.
+       // Never switch encoding with XeTeX/LuaTeX
+       // or if we're in a moving argument or inherit the outer encoding.
        if (runparams.isFullUnicode() || newEnc.name() == "inherit")
+               return make_pair(false, 0);     
+
+       // Only switch for auto-selected legacy encodings (inputenc setting
+       // "auto-legacy" or "auto-legacy-plain").
+       // The "listings" environment can force a switch also with other
+       // encoding settings (it does not support variable width encodings
+       // (utf8, jis, ...) under 8-bit latex engines).
+       if (!force && ((bparams.inputenc != "auto-legacy" && bparams.inputenc != "auto-legacy-plain")
+                                  || runparams.moving_arg))
                return make_pair(false, 0);
 
        Encoding const & oldEnc = *runparams.encoding;
-       bool moving_arg = runparams.moving_arg;
-       // If we switch from/to CJK, we need to switch anyway, despite custom inputenc,
-       // except if we use CJKutf8 or explicitely set inputenc to a CJK encoding
-       bool const from_to_cjk =
-               ((oldEnc.package() == Encoding::CJK && newEnc.package() != Encoding::CJK)
-                || (oldEnc.package() != Encoding::CJK && newEnc.package() == Encoding::CJK))
-               && bparams.encoding().iconvName() != "UTF8"
-               && bparams.encoding().package() != Encoding::CJK;
-       if (!force && !from_to_cjk
-           && ((bparams.inputenc != "auto" && bparams.inputenc != "default") || moving_arg))
-               return make_pair(false, 0);
-
-       // Do nothing if the encoding is unchanged.
-       if (oldEnc.name() == newEnc.name())
+       // Do not switch, if the encoding is unchanged or switching is not supported.
+       if (oldEnc.name() == newEnc.name()
+               || oldEnc.package() == Encoding::japanese
+               || oldEnc.package() == Encoding::none
+               || newEnc.package() == Encoding::none
+               || runparams.for_search)
                return make_pair(false, 0);
-
        // FIXME We ignore encoding switches from/to encodings that do
        // neither support the inputenc package nor the CJK package here.
-       // This does of course only work in special cases (e.g. switch from
-       // tis620-0 to latin1, but the text in latin1 contains ASCII only),
-       // but it is the best we can do
-       //
-       // 2019-01-08 Possibly no longer required since tis620-0 is supported
-       // by inputenc (but check special encodings "utf8-plain" and "default").
-       if (oldEnc.package() == Encoding::none || newEnc.package() == Encoding::none)
-               return make_pair(false, 0);
+       // This may fail for characters not supported by "unicodesymbols"
+       // or for non-ASCII characters in "listings"
+       // but it is the best we can do.
 
        // change encoding
        LYXERR(Debug::LATEX, "Changing LaTeX encoding from "
                   << oldEnc.name() << " to " << newEnc.name());
        os << setEncoding(newEnc.iconvName());
-       if (bparams.inputenc == "default")
+       if (bparams.inputenc == "auto-legacy-plain")
          return make_pair(true, 0);
 
        docstring const inputenc_arg(from_ascii(newEnc.latexName()));
@@ -1644,7 +1737,7 @@ pair<bool, int> switchEncoding(odocstream & os, BufferParams const & bparams,
        switch (newEnc.package()) {
                case Encoding::none:
                case Encoding::japanese:
-                       // shouldn't ever reach here, see above
+                       // shouldn't ever reach here (see above) but avoids warning.
                        return make_pair(true, 0);
                case Encoding::inputenc: {
                        int count = inputenc_arg.length();
@@ -1660,7 +1753,7 @@ pair<bool, int> switchEncoding(odocstream & os, BufferParams const & bparams,
                                state->open_encoding_ = none;
                                count += 7;
                        }
-                       if (runparams.local_font != 0
+                       if (runparams.local_font != nullptr
                            &&  oldEnc.package() == Encoding::CJK) {
                                // within insets, \inputenc switches need
                                // to be embraced within \bgroup...\egroup;
@@ -1669,8 +1762,7 @@ pair<bool, int> switchEncoding(odocstream & os, BufferParams const & bparams,
                                count += 7;
                                state->open_encoding_ = inputenc;
                        }
-                       // with the japanese option, inputenc is omitted.
-                       if (runparams.use_japanese || noswitchmacro)
+                       if (noswitchmacro)
                                return make_pair(true, count);
                        os << "\\inputencoding{" << inputenc_arg << '}';
                        return make_pair(true, count + 16);
@@ -1687,9 +1779,8 @@ pair<bool, int> switchEncoding(odocstream & os, BufferParams const & bparams,
                                os << "\\egroup";
                                count += 7;
                        }
-                       docstring const cjkenc = (bparams.encoding().iconvName() == "UTF-8"
-                                                                         ? from_ascii("UTF8") : from_ascii(newEnc.latexName()));
-                       os << "\\begin{CJK}{" << cjkenc << "}{"
+                       os << "\\begin{CJK}{"
+                          << from_ascii(newEnc.latexName()) << "}{"
                           << from_ascii(bparams.fonts_cjk) << "}";
                        state->open_encoding_ = CJK;
                        return make_pair(true, count + 15);