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Highlighting multiline text in quotes



  • Code:

    quotationFormat.setForeground(Qt::darkGreen);
    rule.pattern = QRegularExpression(QStringLiteral("\".*\""));
    rule.format = quotationFormat;
    highlightingRules.append(rule);
    

    highlights text only to the end of the line.
    How to make any number of lines highlighted?



  • @MyNick-0
    Difficult to know when the types of quotationFormat and highlightingRules are not mentioned....

    In the absence of that, regular expression for that is usually

    QStringLiteral("\"(.|\\n)*\"")
    

    Or you can use the QRegularExpression::DotMatchesEverythingOption option from https://doc.qt.io/qt-5/qregularexpression.html#PatternOption-enum as an argument to QRegularExpression() and stick with your original pattern.



  • this expression doesn't work for me.

    You need to highlight several lines of subrad, for example:
    "str 1
    str 2
    str 3"



  • @MyNick-0 said in Highlighting multiline text in quotes:

    this expression doesn't work for me.

    Who knows, since you still don't give any context....

    Try matching the regular expression I gave you against a C string like "Hello\\nGoodbye\\nForever".



  • i have code from documentation:

    #include "highlighter.h"
    
    Highlighter::Highlighter(QTextDocument *parent)
        : QSyntaxHighlighter(parent)
    {
        HighlightingRule rule;
    
        //functionFormat.setFontItalic(true);
        //functionFormat.setFontWeight(QFont::Bold);
        functionFormat.setForeground(QColor(00, 00, 00));
        rule.pattern = QRegularExpression(QStringLiteral("\\b[A-Za-z0-9_]+(?=\\()"));
        rule.format = functionFormat;
        highlightingRules.append(rule);
    
        keywordFormat.setForeground(QColor(00, 80, 80));
        keywordFormat.setFontWeight(QFont::Bold);
        const QString keywordPatternsC[] = {
            QStringLiteral("\\becho\\b"), QStringLiteral("\\bclass\\b"), QStringLiteral("\\bconst\\b"),
            QStringLiteral("\\bdouble\\b"), QStringLiteral("\\benum\\b"), QStringLiteral("\\bexplicit\\b"),
            QStringLiteral("\\bfriend\\b"), QStringLiteral("\\binline\\b"), QStringLiteral("\\bint\\b"),
            QStringLiteral("\\blong\\b"), QStringLiteral("\\bnamespace\\b"), QStringLiteral("\\boperator\\b"),
            QStringLiteral("\\bprivate\\b"), QStringLiteral("\\bprotected\\b"), QStringLiteral("\\bpublic\\b"),
            QStringLiteral("\\bshort\\b"), QStringLiteral("\\bsignals\\b"), QStringLiteral("\\bsigned\\b"),
            QStringLiteral("\\bslots\\b"), QStringLiteral("\\bstatic\\b"), QStringLiteral("\\bstruct\\b"),
            QStringLiteral("\\btemplate\\b"), QStringLiteral("\\btypedef\\b"), QStringLiteral("\\btypename\\b"),
            QStringLiteral("\\bunion\\b"), QStringLiteral("\\bunsigned\\b"), QStringLiteral("\\bvirtual\\b"),
            QStringLiteral("\\bvoid\\b"), QStringLiteral("\\bvolatile\\b"), QStringLiteral("\\bbool\\b")
        };
        for (const QString &pattern : keywordPatterns) {
            rule.pattern = QRegularExpression(pattern);
            rule.format = keywordFormat;
            highlightingRules.append(rule);
        }
    
        classFormat.setFontWeight(QFont::Bold);
        classFormat.setForeground(Qt::darkMagenta);
        rule.pattern = QRegularExpression(QStringLiteral("\\bQ[A-Za-z]+\\b"));
        rule.format = classFormat;
        highlightingRules.append(rule);
    
        quotationFormat.setForeground(QColor(80, 00, 00));//Qt::darkGreen
        rule.pattern = QRegularExpression(QStringLiteral("\"(.|\\n)*\""));
        rule.format = quotationFormat;
        highlightingRules.append(rule);
    
        singleLineCommentFormat.setForeground(Qt::gray);
        rule.pattern = QRegularExpression(QStringLiteral("#[^\n]*|//[^\n]*"));//"//[^\n]*"
        rule.format = singleLineCommentFormat;
        highlightingRules.append(rule);
    
        multiLineCommentFormat.setForeground(Qt::gray);
    
        commentStartExpression = QRegularExpression(QStringLiteral("/\\*"));
        commentEndExpression = QRegularExpression(QStringLiteral("\\*/"));
    }
    
    void Highlighter::highlightBlock(const QString &text)
    {
        for (const HighlightingRule &rule : qAsConst(highlightingRules)) {
            QRegularExpressionMatchIterator matchIterator = rule.pattern.globalMatch(text);
            while (matchIterator.hasNext()) {
                QRegularExpressionMatch match = matchIterator.next();
                setFormat(match.capturedStart(), match.capturedLength(), rule.format);
            }
        }
        setCurrentBlockState(0);
    
        int startIndex = 0;
        if (previousBlockState() != 1)
            startIndex = text.indexOf(commentStartExpression);
    
        while (startIndex >= 0) {
            QRegularExpressionMatch match = commentEndExpression.match(text, startIndex);
            int endIndex = match.capturedStart();
            int commentLength = 0;
            if (endIndex == -1) {
                setCurrentBlockState(1);
                commentLength = text.length() - startIndex;
            } else {
                commentLength = endIndex - startIndex
                                + match.capturedLength();
            }
            setFormat(startIndex, commentLength, multiLineCommentFormat);
            startIndex = text.indexOf(commentStartExpression, startIndex + commentLength);
        }
    }
    

    And I use it like this:

    highlighter = new Highlighter(textEdit->document());
    


  • My operating system, Windows 7 x64



  • @MyNick-0
    This is a lot of code. I don't know why/whether the multiline does not work for you. I gave you the correct regular expression for you to test out. It's your job to reduce the code to minimal if you are having a problem.

    Meanwhile, your "#[^\n]*|//[^\n]*" at least is wrong, I don't know whether that has any effect.



  • i am using regex you gave me here:

    quotationFormat.setForeground(QColor(80, 00, 00));
    rule.pattern = QRegularExpression(QStringLiteral("\"(.|\\n)*\""));
    rule.format = quotationFormat;
    highlightingRules.append(rule);
    


  • @MyNick-0
    I don't know about the behaviour of QSyntaxHighlighter which you have now started mentioning, not mentioned in your topic title or original question. The regular expression I gave should be right as a regular expression.

    However, in your case of wanting leading & trailing " characters, and * being greedy, you would probably want something more like (even if it works)

    "\"([^\"]|\\n)*\""
    

    Even then it won't work right if your C literal string contain any embedded \" sequences....

    Start by removing all your code except for this one and only one rule, while you see its behaviour/debug. Test that the reg ex I have given you does work against a multiline string, independent of anything to do with QSyntaxHighlighter.

    Then, I think but don't know, read carefully what https://doc.qt.io/qt-5/qsyntaxhighlighter.html#details says:

    Some syntaxes can have constructs that span several text blocks. For example, a C++ syntax highlighter should be able to cope with /*...*/ multiline comments. To deal with these cases it is necessary to know the end state of the previous text block (e.g. "in comment").

    Since the quoted-string-multiline-format is similar to the C-comment-multiline-format, and the same code you are copying from has special code for that which does not use newline-in-regular-experssion, I'm guessing you need to implement multiline string in an analogous way to how that implements the code for its multiLineCommentFormat? It says:

    But the multiline comment needs special care due to the design of the QSyntaxHighlighter class.


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