Fix fuer #209

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@3468 a592a061-630c-0410-9148-cb99ea01b6c8

src/mathed/math_charinset.h

@@ -56,6 +56,8 @@ public:
 	void handleFont(MathTextCodes t);
 	///
 	bool match(MathInset *) const;
+	/// identifies complicated things that need braces if used as arg
+	bool needsBraces() const { return false; }
 
 private:
 	/// the character

src/mathed/math_inset.h

@@ -212,6 +212,8 @@ public:
 	virtual MathTextCodes code() const { return LM_TC_MIN; }
 	/// identifies things that can get \limits or \nolimits
 	virtual bool takesLimits() const { return false; }
+	/// identifies complicated things that need braces if used as arg
+	virtual bool needsBraces() const { return true; }
 
 	///
 	virtual void edit(BufferView *, int, int, unsigned int) {}

src/mathed/math_parser.C

@@ -798,7 +798,10 @@ void Parser::parse_into(MathArray & array, unsigned flags, MathTextCodes code)
 #warning this might be wrong in general!
 #endif
 			// ignore braces around simple items
-			if (ar.size() == 1 || (ar.size() == 2 && ar.back()->asScriptInset())) {
+			if ((ar.size() == 1 && !ar.front()->needsBraces()
+       || (ar.size() == 2 && !ar.front()->needsBraces()
+			                    && ar.back()->asScriptInset())))
+			{
 				array.push_back(ar);
 			} else {
 				array.push_back(MathAtom(new MathBraceInset));

src/mathed/math_symbolinset.h

@@ -37,6 +37,8 @@ public:
 	bool match(MathInset *) const;
 	/// request "external features"
 	void validate(LaTeXFeatures & features) const;
+	/// identifies complicated things that need braces if used as arg
+	bool needsBraces() const { return false; }
 
 	///
 	void normalize(NormalStream &) const;