[LyX/master] Make language nesting code more readable

[Georg Baum]

commit 1eaa2366bfb9c0809b5e4c5a86eef2033f341b25
Author: Georg Baum <b...@lyx.org>
Date:   Tue Oct 27 22:36:52 2015 +0100

    Make language nesting code more readable
    
    This is a tiny simplification that makes understanding the code more easy 
and
    will help in fixing the remaining regressions. The logic remains the same, 
no
    export test result is changed.

diff --git a/src/output_latex.cpp b/src/output_latex.cpp
index 7b63381..3145025 100644
--- a/src/output_latex.cpp
+++ b/src/output_latex.cpp
@@ -637,6 +637,8 @@ 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;
        // The document's language
        Language const * const doc_language = bparams.language;
        // The language that was in effect when the environment this paragraph 
is
@@ -672,6 +674,9 @@ void TeXOnePar(Buffer const & buf,
                getPolyglossiaEnvName(prev_language) : prev_language->babel();
        string const outer_lang = use_polyglossia ?
                getPolyglossiaEnvName(outer_language) : outer_language->babel();
+       string const nextpar_lang = nextpar_language ? (use_polyglossia ?
+               getPolyglossiaEnvName(nextpar_language) :
+               nextpar_language->babel()) : string();
        string lang_begin_command = use_polyglossia ?
                "\\begin{$$lang}$$opts" : lyxrc.language_command_begin;
        string lang_end_command = use_polyglossia ?
@@ -934,13 +939,12 @@ void TeXOnePar(Buffer const & buf,
                && runparams.local_font != 0
                && runparams.local_font->isRightToLeft() != 
par_language->rightToLeft()
                // are we about to close the language?
-               &&((nextpar && par_language->babel() != 
(nextpar->getParLanguage(bparams))->babel())
-                  || (runparams.isLastPar && par_language->babel() != 
outer_language->babel()));
+               &&((nextpar && par_lang != nextpar_lang)
+                  || (runparams.isLastPar && par_lang != outer_lang));
 
        if (closing_rtl_ltr_environment
            || (runparams.isLastPar
-               && ((!use_polyglossia && par_language->babel() != 
outer_language->babel())
-                   || (use_polyglossia && par_language->polyglossia() != 
outer_language->polyglossia())))) {
+               && par_lang != outer_lang)) {
                // Since \selectlanguage write the language to the aux file,
                // we need to reset the language at the end of footnote or
                // float.
@@ -1000,7 +1004,7 @@ void TeXOnePar(Buffer const & buf,
        // also if the next paragraph is a multilingual environment (because of 
nesting)
        if (nextpar
                && state->open_encoding_ == CJK
-               && (nextpar->getParLanguage(bparams)->encoding()->package() != 
Encoding::CJK
+               && (nextpar_language->encoding()->package() != Encoding::CJK
                   || (nextpar->layout().isEnvironment() && 
nextpar->isMultiLingual(bparams)))
                // inbetween environments, CJK has to be closed later (nesting!)
                && (!style.isEnvironment() || 
!nextpar->layout().isEnvironment())) {