[patch] Source highlighting of comments

[Bernhard Reiter]

ATM, in the source view (eg in the preamble), the last character before
a comment (ie percent sign) is greyed out as if part of the comment. The
attached patch should fix this behavior.

Bernhard Reiter

Index: src/frontends/qt4/LaTeXHighlighter.cpp
===================================================================
--- src/frontends/qt4/LaTeXHighlighter.cpp	(Revision 21664)
+++ src/frontends/qt4/LaTeXHighlighter.cpp	(Arbeitskopie)
@@ -85,13 +85,20 @@
 		setFormat(index, length, keywordFormat);
 		index = text.indexOf(exprKeyword, index + length);
 	}
-	// comment
-	static const QRegExp exprComment("(^|[^\\\\])%.*$");
-	index = text.indexOf(exprComment);
+	// %comment
+	// If QRegExp supported look-behind, we'd get the right 
+	// index by using an analogue construct as above with
+	//    QRegExp exprComment"(?<!\\\\)%.*$");
+	// and wouldn't need the following special magic.
+	QRegExp exprComment("(?:^|[^\\\\])(%).*$"); 
+	text.indexOf(exprComment);
+	index = exprComment.pos(1);
 	while (index >= 0) {
-		int const length = exprComment.matchedLength();
+		int const length = exprComment.matchedLength() 
+						 - (index - exprComment.pos(0));
 		setFormat(index, length, commentFormat);
-		index = text.indexOf(exprComment, index + length);
+		text.indexOf(exprComment, index + length);
+		index = exprComment.pos(1);
 	}
 }