Simplify the TexRow information for mathed output

Replace the manual manipulation of a stack of RowEntries with a Changer
function. When I introduced the stack of RowEntries, I did not know about the
Changer mechanism.

src/mathed/InsetMathGrid.cpp

@@ -34,7 +34,6 @@
 #include "support/docstream.h"
 #include "support/gettext.h"
 #include "support/lstrings.h"
-
 #include "support/lassert.h"
 
 #include <sstream>
@@ -1275,7 +1274,7 @@ void InsetMathGrid::write(WriteStream & os,
 				++col;
 				continue;
 			}
-			os.pushRowEntry(entry);
+			Changer dummy = os.changeRowEntry(entry);
 			if (cellinfo_[idx].multi_ == CELL_BEGIN_OF_MULTICOLUMN) {
 				size_t s = col + 1;
 				while (s < ncols() &&
@@ -1293,7 +1292,6 @@ void InsetMathGrid::write(WriteStream & os,
 				os << '}';
 			os << eocString(col + nccols - 1, lastcol);
 			col += nccols;
-			os.popRowEntry();
 		}
 		eol = eolString(row, os.fragile(), os.latex(), last_eoln);
 		os << eol;

src/mathed/InsetMathNest.cpp

@@ -59,12 +59,12 @@
 #include "frontends/Painter.h"
 #include "frontends/Selection.h"
 
-#include "support/lassert.h"
 #include "support/debug.h"
+#include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/lassert.h"
 #include "support/lstrings.h"
 #include "support/textutils.h"
-#include "support/docstream.h"
 
 #include <algorithm>
 #include <sstream>
@@ -380,9 +380,8 @@ void InsetMathNest::write(WriteStream & os) const
 	docstring const latex_name = name();
 	os << '\\' << latex_name;
 	for (size_t i = 0; i < nargs(); ++i) {
-		os.pushRowEntry(TexRow::mathEntry(id(),i));
+		Changer dummy = os.changeRowEntry(TexRow::mathEntry(id(),i));
 		os << '{' << cell(i) << '}';
-		os.popRowEntry();
 	}
 	if (nargs() == 0)
 		os.pendingSpace(true);
@@ -408,13 +407,9 @@ void InsetMathNest::latex(otexstream & os, OutputParams const & runparams) const
 			runparams.dryrun ? WriteStream::wsDryrun : WriteStream::wsDefault,
 			runparams.encoding);
 	wi.canBreakLine(os.canBreakLine());
-	if (runparams.lastid != -1) {
-		wi.pushRowEntry(os.texrow().textEntry(runparams.lastid,
-											  runparams.lastpos));
-		write(wi);
-		wi.popRowEntry();
-	} else
-		write(wi);
+	Changer dummy = wi.changeRowEntry(os.texrow().textEntry(runparams.lastid,
+	                                                        runparams.lastpos));
+	write(wi);
 	// Reset parbreak status after a math inset.
 	os.lastChar(0);
 	os.canBreakLine(wi.canBreakLine());

src/mathed/MathStream.cpp

@@ -15,8 +15,9 @@
 #include "MathData.h"
 #include "MathExtern.h"
 
-#include "support/textutils.h"
 #include "support/docstring.h"
+#include "support/RefChanger.h"
+#include "support/textutils.h"
 
 #include <algorithm>
 #include <cstring>
@@ -123,18 +124,20 @@ WriteStream & operator<<(WriteStream & ws, docstring const & s)
 
 WriteStream::WriteStream(otexrowstream & os, bool fragile, bool latex,
 						 OutputType output, Encoding const * encoding)
-	: os_(os), fragile_(fragile), firstitem_(false), latex_(latex),
-	  output_(output), pendingspace_(false), pendingbrace_(false),
-	  textmode_(false), locked_(0), ascii_(0), canbreakline_(true),
-	  line_(0), encoding_(encoding)
-{}
+	: WriteStream(os)
+{
+	fragile_ = fragile;
+	latex_ = latex;
+	output_ = output;
+	encoding_ = encoding;
+}
 
 
 WriteStream::WriteStream(otexrowstream & os)
 	: os_(os), fragile_(false), firstitem_(false), latex_(false),
 	  output_(wsDefault), pendingspace_(false), pendingbrace_(false),
 	  textmode_(false), locked_(0), ascii_(0), canbreakline_(true),
-	  line_(0), encoding_(0) 
+	  line_(0), encoding_(0), row_entry_(TexRow::row_none)
 {}
 
 
@@ -183,26 +186,17 @@ void WriteStream::asciiOnly(bool ascii)
 }
 
 
-void WriteStream::pushRowEntry(TexRow::RowEntry entry)
+Changer WriteStream::changeRowEntry(TexRow::RowEntry entry)
 {
-	outer_row_entries_.push_back(entry);
-}
-
-
-void WriteStream::popRowEntry()
-{
-	if (!outer_row_entries_.empty())
-		outer_row_entries_.pop_back();
+	return make_change(row_entry_, entry);
 }
 
 
 bool WriteStream::startOuterRow()
 {
-	size_t n = outer_row_entries_.size();
-	if (n > 0)
-		return texrow().start(outer_row_entries_[n - 1]);
-	else
+	if (TexRow::isNone(row_entry_))
 		return false;
+	return texrow().start(row_entry_);
 }
 
 

src/mathed/MathStream.h

@@ -12,11 +12,12 @@
 #ifndef MATH_MATHMLSTREAM_H
 #define MATH_MATHMLSTREAM_H
 
-#include "support/strfwd.h"
-
 #include "InsetMath.h"
 #include "texstream.h"
 
+#include "support/Changer.h"
+#include "support/strfwd.h"
+
 
 namespace lyx {
 
@@ -87,11 +88,8 @@ public:
 	/// LaTeX encoding
 	Encoding const * encoding() const { return encoding_; }
 
-	/// maintains a stack of texrow informations about outer math insets.
-	/// push an entry
-	void pushRowEntry(TexRow::RowEntry entry);
-	/// pop an entry
-	void popRowEntry();
+	/// Temporarily change the TexRow information about the outer row entry.
+	Changer changeRowEntry(TexRow::RowEntry entry);
 	/// TexRow::starts the innermost outer math inset
 	/// returns true if the outer row entry will appear at this line
 	bool startOuterRow();
@@ -122,8 +120,8 @@ private:
 	int line_;
 	///
 	Encoding const * encoding_;
-	///
-	std::vector<TexRow::RowEntry> outer_row_entries_;
+	/// Row entry we are in
+	TexRow::RowEntry row_entry_;
 };
 
 ///