Sort the language nesting mess with polyglossia

When using polyglossia, lyx was making a real mess when changing
language inside nested insets. The \begin{language} and
\end{language} commands were not well paired such that they could
easily occur just before and after the start or end of an
environment. Of course this was causing latex errors such that
"\begin{otherlanguage} ended by \end{environment}".
There may still be some cases I did not take into account.

diff --git a/src/output_latex.cpp b/src/output_latex.cpp
index f5c6a10888bae07547d420bf81af19d971a6059d..b5846260bb0c64cbc1819e1a0fb94b8e82b0390d 100644 (file)
--- a/src/output_latex.cpp
+++ b/src/output_latex.cpp
@@ -42,6 +42,7 @@
 #include <QThreadStorage>
 
 #include <list>
+#include <stack>
 
 using namespace std;
 using namespace lyx::support;
@@ -61,13 +62,15 @@ enum OpenEncoding {
 struct OutputState
 {
        OutputState() : open_encoding_(none), cjk_inherited_(0),
-                       prev_env_language_(0), open_polyglossia_lang_("")
+                       prev_env_language_(0), nest_level_(0)
        {
        }
        OpenEncoding open_encoding_;
        int cjk_inherited_;
        Language const * prev_env_language_;
-       string open_polyglossia_lang_;
+       int nest_level_;
+       stack<int> lang_switch_depth_;          // Both are always empty when
+       stack<string> open_polyglossia_lang_;   // not using polyglossia
 };
 
 
@@ -82,6 +85,32 @@ OutputState * getOutputState()
 }
 
 
+string const & openPolyglossiaLang(OutputState const * state)
+{
+       // Return a reference to the last active language opened with
+       // polyglossia. If none or when using babel, return a reference
+       // to an empty string.
+
+       static string const empty;
+
+       return state->open_polyglossia_lang_.empty()
+               ? empty
+               : state->open_polyglossia_lang_.top();
+}
+
+
+bool atSameLastLangSwitchDepth(OutputState const * state)
+{
+       // Return true if the actual nest level is the same at which the
+       // language was switched when using polyglossia. Instead, return
+       // always true when using babel.
+
+       return state->lang_switch_depth_.size() == 0
+                       ? true
+                       : state->lang_switch_depth_.top() == state->nest_level_;
+}
+
+
 string const getPolyglossiaEnvName(Language const * lang)
 {
        string result = lang->polyglossia();
@@ -163,9 +192,11 @@ static TeXEnvironmentData prepareEnvironment(Buffer const & buf,
        string const lang_end_command = use_polyglossia ?
                "\\end{$$lang}" : lyxrc.language_command_end;
 
+       // For polyglossia, switch language outside of environment, if possible.
        if (par_lang != prev_par_lang) {
                if (!lang_end_command.empty() &&
                    prev_par_lang != doc_lang &&
+                   atSameLastLangSwitchDepth(state) &&
                    !prev_par_lang.empty()) {
                        os << from_ascii(subst(
                                lang_end_command,
@@ -173,10 +204,15 @@ static TeXEnvironmentData prepareEnvironment(Buffer const & buf,
                                prev_par_lang))
                          // the '%' is necessary to prevent unwanted whitespace
                          << "%\n";
+                       if (use_polyglossia) {
+                               state->lang_switch_depth_.pop();
+                               state->open_polyglossia_lang_.pop();
+                       }
                }
 
                if ((lang_end_command.empty() ||
-                   par_lang != doc_lang) &&
+                   par_lang != doc_lang ||
+                   par_lang != openPolyglossiaLang(state)) &&
                    !par_lang.empty()) {
                            string bc = use_polyglossia ?
                                        getPolyglossiaBegin(lang_begin_command, par_lang,
@@ -185,6 +221,10 @@ static TeXEnvironmentData prepareEnvironment(Buffer const & buf,
                            os << bc;
                            // the '%' is necessary to prevent unwanted whitespace
                            os << "%\n";
+                           if (use_polyglossia) {
+                                   state->lang_switch_depth_.push(state->nest_level_);
+                                   state->open_polyglossia_lang_.push(par_lang);
+                           }
                }
        }
 
@@ -197,8 +237,7 @@ static TeXEnvironmentData prepareEnvironment(Buffer const & buf,
        }
 
        if (style.isEnvironment()) {
-               if (par_lang != doc_lang)
-                       state->open_polyglossia_lang_ = par_lang;
+               state->nest_level_ += 1;
                os << "\\begin{" << from_ascii(style.latexname()) << '}';
                if (!style.latexargs().empty()) {
                        OutputParams rp = runparams;
@@ -248,8 +287,20 @@ static void finishEnvironment(otexstream & os, OutputParams const & runparams,
        }
 
        if (data.style->isEnvironment()) {
-               os << breakln
-                  << "\\end{" << from_ascii(data.style->latexname()) << "}\n";
+               os << breakln;
+               // Close any polyglossia language opened at this nest level
+               if (runparams.use_polyglossia) {
+                       OutputState * state = getOutputState();
+                       while (state->lang_switch_depth_.size()
+                              && state->lang_switch_depth_.top() == state->nest_level_) {
+                               os << "\\end{" << openPolyglossiaLang(state)
+                                  << "}%\n";
+                               state->lang_switch_depth_.pop();
+                               state->open_polyglossia_lang_.pop();
+                       }
+               }
+               state->nest_level_ -= 1;
+               os << "\\end{" << from_ascii(data.style->latexname()) << "}\n";
                state->prev_env_language_ = data.par_language;
                if (runparams.encoding != data.prev_encoding) {
                        runparams.encoding = data.prev_encoding;
@@ -688,7 +739,8 @@ void TeXOnePar(Buffer const & buf,
        string lang_command_termination = "%\n";
 
        // In some insets (such as Arguments), we cannot use \selectlanguage
-       bool const localswitch = text.inset().forceLocalFontSwitch();
+       bool const localswitch = text.inset().forceLocalFontSwitch()
+                       || (use_polyglossia && text.inset().forcePlainLayout());
        if (localswitch) {
                lang_begin_command = use_polyglossia ?
                            "\\text$$lang$$opts{" : lyxrc.language_command_local;
@@ -705,14 +757,17 @@ void TeXOnePar(Buffer const & buf,
        {
                if (!lang_end_command.empty() &&
                    prev_lang != outer_lang &&
-                   !prev_lang.empty())
+                   !prev_lang.empty() &&
+                   (!use_polyglossia || !style.isEnvironment()))
                {
                        os << from_ascii(subst(lang_end_command,
                                "$$lang",
                                prev_lang))
                           << lang_command_termination;
-                       if (prev_lang == state->open_polyglossia_lang_)
-                               state->open_polyglossia_lang_ = "";
+                       if (use_polyglossia && !localswitch) {
+                               state->lang_switch_depth_.pop();
+                               state->open_polyglossia_lang_.pop();
+                       }
                }
 
                // We need to open a new language if we couldn't close the previous
@@ -720,7 +775,9 @@ void TeXOnePar(Buffer const & buf,
                // the previous one, if the current language is different than the
                // outer_language (which is currently in effect once the previous one
                // is closed).
-               if ((lang_end_command.empty() || par_lang != outer_lang)
+               if ((lang_end_command.empty() || par_lang != outer_lang
+                    || (!use_polyglossia
+                        || (style.isEnvironment() && par_lang != prev_lang)))
                        && !par_lang.empty()) {
                        // If we're inside an inset, and that inset is within an \L or \R
                        // (or equivalents), then within the inset, too, any opposite
@@ -760,12 +817,17 @@ void TeXOnePar(Buffer const & buf,
                        }
                        // With CJK, the CJK tag has to be closed first (see below)
                        if (runparams.encoding->package() != Encoding::CJK
+                           && par_lang != openPolyglossiaLang(state)
                            && !par_lang.empty()) {
                                string bc = use_polyglossia ?
                                          getPolyglossiaBegin(lang_begin_command, par_lang, par_language->polyglossiaOpts())
                                          : subst(lang_begin_command, "$$lang", par_lang);
                                os << bc;
                                os << lang_command_termination;
+                               if (use_polyglossia && !localswitch) {
+                                       state->lang_switch_depth_.push(state->nest_level_);
+                                       state->open_polyglossia_lang_.push(par_lang);
+                               }
                        }
                }
        }
@@ -817,12 +879,17 @@ void TeXOnePar(Buffer const & buf,
                                }
                                // With CJK, the CJK tag had to be closed first (see above)
                                if (runparams.encoding->package() == Encoding::CJK
+                                   && par_lang != openPolyglossiaLang(state)
                                    && !par_lang.empty()) {
                                        os << from_ascii(subst(
                                                lang_begin_command,
                                                "$$lang",
                                                par_lang))
                                        << lang_command_termination;
+                                       if (use_polyglossia && !localswitch) {
+                                               state->lang_switch_depth_.push(state->nest_level_);
+                                               state->open_polyglossia_lang_.push(par_lang);
+                                       }
                                }
                                runparams.encoding = encoding;
                        }
@@ -893,9 +960,15 @@ void TeXOnePar(Buffer const & buf,
 
        bool pending_newline = false;
        bool unskip_newline = false;
+       bool close_lang_switch = false;
        switch (style.latextype) {
        case LATEX_ITEM_ENVIRONMENT:
        case LATEX_LIST_ENVIRONMENT:
+               if (nextpar && par_lang != nextpar_lang
+                   && nextpar->getDepth() == par.getDepth()
+                   || (atSameLastLangSwitchDepth(state) && nextpar
+                           && nextpar->getDepth() < par.getDepth()))
+                       close_lang_switch = use_polyglossia;
                if (nextpar && par.params().depth() < nextpar->params().depth())
                        pending_newline = true;
                break;
@@ -903,9 +976,13 @@ void TeXOnePar(Buffer const & buf,
                // if its the last paragraph of the current environment
                // skip it otherwise fall through
                if (nextpar
-                       && (nextpar->layout() != par.layout()
-                       || nextpar->params().depth() != par.params().depth()))
+                   && ((nextpar->layout() != par.layout()
+                          || nextpar->params().depth() != par.params().depth())
+                       || (!use_polyglossia || par_lang != nextpar_lang)))
+               {
+                       close_lang_switch = use_polyglossia;
                        break;
+               }
        }
 
        // fall through possible
@@ -946,13 +1023,15 @@ void TeXOnePar(Buffer const & buf,
                   || (runparams.isLastPar && par_lang != outer_lang));
 
        if (closing_rtl_ltr_environment
-           || (runparams.isLastPar
-               && par_lang != outer_lang)) {
+           || ((runparams.isLastPar || close_lang_switch)
+               && (par_lang != outer_lang || (use_polyglossia
+                                               && style.isEnvironment()
+                                               && par_lang != nextpar_lang)))) {
                // Since \selectlanguage write the language to the aux file,
                // we need to reset the language at the end of footnote or
                // float.
 
-               if (pending_newline)
+               if (pending_newline || close_lang_switch)
                        os << '\n';
 
                // when the paragraph uses CJK, the language has to be closed earlier
@@ -967,7 +1046,8 @@ void TeXOnePar(Buffer const & buf,
                                string const current_lang = use_polyglossia
                                        ? getPolyglossiaEnvName(current_language)
                                        : current_language->babel();
-                               if (!current_lang.empty()) {
+                               if (!current_lang.empty()
+                                   && current_lang != openPolyglossiaLang(state)) {
                                        string bc = use_polyglossia ?
                                                    getPolyglossiaBegin(lang_begin_command, current_lang,
                                                                        current_language->polyglossiaOpts())
@@ -975,16 +1055,39 @@ void TeXOnePar(Buffer const & buf,
                                        os << bc;
                                        pending_newline = !localswitch;
                                        unskip_newline = !localswitch;
+                                       if (use_polyglossia && !localswitch) {
+                                               state->lang_switch_depth_.push(
+                                                               state->nest_level_);
+                                               state->open_polyglossia_lang_.push(current_lang);
+                                       }
                                }
                        } else if (!par_lang.empty()) {
                                // If we are in an environment, we have to close the "outer" language afterwards
-                               if (!style.isEnvironment() || state->open_polyglossia_lang_ != par_lang) {
+                               string const & pol_lang = openPolyglossiaLang(state);
+                               if (!style.isEnvironment()
+                                   || (close_lang_switch
+                                       && atSameLastLangSwitchDepth(state)
+                                       && par_lang != outer_lang
+                                       && (par_lang != pol_lang
+                                           || (pol_lang != outer_lang
+                                               && nextpar
+                                               && style != nextpar->layout())))
+                                   || (atSameLastLangSwitchDepth(state)
+                                       && state->lang_switch_depth_.size()
+                                       && pol_lang != par_lang))
+                               {
+                                       if (use_polyglossia && !localswitch)
+                                               os << breakln;
                                        os << from_ascii(subst(
                                                lang_end_command,
                                                "$$lang",
                                                par_lang));
                                        pending_newline = !localswitch;
                                        unskip_newline = !localswitch;
+                                       if (use_polyglossia && !localswitch) {
+                                               state->lang_switch_depth_.pop();
+                                               state->open_polyglossia_lang_.pop();
+                                       }
                                }
                        }
                }
@@ -1000,7 +1103,7 @@ void TeXOnePar(Buffer const & buf,
                        // prevent unwanted whitespace
                        os << '%';
                if (!os.afterParbreak() && !last_was_separator)
-                       os << '\n';
+                       os << breakln;
        }
 
        // if this is a CJK-paragraph and the next isn't, close CJK
@@ -1266,8 +1369,10 @@ void latexParagraphs(Buffer const & buf,
                                        "$$lang",
                                        mainlang))
                        << '\n';
-               if (state->open_polyglossia_lang_ == mainlang)
-                       state->open_polyglossia_lang_ = "";
+               if (runparams.use_polyglossia) {
+                       state->lang_switch_depth_.pop();
+                       state->open_polyglossia_lang_.pop();
+               }
        }
 
        // If the last paragraph is an environment, we'll have to close
@@ -1277,12 +1382,16 @@ void latexParagraphs(Buffer const & buf,
                state->open_encoding_ = none;
        }
        // Likewise for polyglossia
-       if (maintext && !is_child && state->open_polyglossia_lang_ != "") {
+       string const & pol_lang = openPolyglossiaLang(state);
+       if (maintext && !is_child && !pol_lang.empty()) {
                os << from_utf8(subst(lang_end_command,
                                        "$$lang",
-                                       state->open_polyglossia_lang_))
+                                       pol_lang))
                   << '\n';
-               state->open_polyglossia_lang_ = "";
+               if (runparams.use_polyglossia) {
+                       state->lang_switch_depth_.pop();
+                       state->open_polyglossia_lang_.pop();
+               }
        }
 
        // reset inherited encoding