integrate syntax highlight code from example (uses c++ syntax currently)

tools/lammps-gui/CMakeLists.txt

@@ -55,6 +55,8 @@ set(PROJECT_SOURCES
   main.cpp
   codeeditor.cpp
   codeeditor.h
+  highlighter.cpp
+  highlighter.h
   linenumberarea.h
   lammpsgui.cpp
   lammpsgui.h

tools/lammps-gui/highlighter.cpp

@@ -0,0 +1,98 @@
+/* ----------------------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   https://www.lammps.org/, Sandia National Laboratories
+   LAMMPS development team: developers@lammps.org
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+#include "highlighter.h"
+
+Highlighter::Highlighter(QTextDocument *parent) : QSyntaxHighlighter(parent)
+{
+    HighlightingRule rule;
+
+    keywordFormat.setForeground(Qt::darkBlue);
+    keywordFormat.setFontWeight(QFont::Bold);
+    const QString keywordPatterns[] = {
+        QStringLiteral("\\bchar\\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(Qt::darkGreen);
+    rule.pattern = QRegularExpression(QStringLiteral("\".*\""));
+    rule.format  = quotationFormat;
+    highlightingRules.append(rule);
+
+    functionFormat.setFontItalic(true);
+    functionFormat.setForeground(Qt::blue);
+    rule.pattern = QRegularExpression(QStringLiteral("\\b[A-Za-z0-9_]+(?=\\()"));
+    rule.format  = functionFormat;
+    highlightingRules.append(rule);
+    singleLineCommentFormat.setForeground(Qt::red);
+    rule.pattern = QRegularExpression(QStringLiteral("//[^\n]*"));
+    rule.format  = singleLineCommentFormat;
+    highlightingRules.append(rule);
+
+    multiLineCommentFormat.setForeground(Qt::red);
+
+    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);
+    }
+}
+// Local Variables:
+// c-basic-offset: 4
+// End:

tools/lammps-gui/highlighter.h

@@ -0,0 +1,52 @@
+/* -*- c++ -*- ----------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   https://www.lammps.org/, Sandia National Laboratories
+   LAMMPS development team: developers@lammps.org
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+#ifndef HIGHLIGHTER_H
+#define HIGHLIGHTER_H
+
+#include <QSyntaxHighlighter>
+#include <QRegularExpression>
+#include <QTextCharFormat>
+
+class Highlighter : public QSyntaxHighlighter
+{
+    Q_OBJECT
+
+public:
+    Highlighter(QTextDocument *parent = 0);
+
+protected:
+    void highlightBlock(const QString &text) override;
+
+private:
+    struct HighlightingRule
+    {
+        QRegularExpression pattern;
+        QTextCharFormat format;
+    };
+    QVector<HighlightingRule> highlightingRules;
+
+    QRegularExpression commentStartExpression;
+    QRegularExpression commentEndExpression;
+
+    QTextCharFormat keywordFormat;
+    QTextCharFormat classFormat;
+    QTextCharFormat singleLineCommentFormat;
+    QTextCharFormat multiLineCommentFormat;
+    QTextCharFormat quotationFormat;
+    QTextCharFormat functionFormat;
+};
+#endif
+// Local Variables:
+// c-basic-offset: 4
+// End:

tools/lammps-gui/lammpsgui.cpp

@@ -10,7 +10,9 @@
 
    See the README file in the top-level LAMMPS directory.
 ------------------------------------------------------------------------- */
+
 #include "lammpsgui.h"
+#include "highlighter.h"
 #include "ui_lammpsgui.h"
 
 #include <QFileDialog>
@@ -34,6 +36,7 @@ LammpsGui::LammpsGui(QWidget *parent, const char *filename) :
     text_font.setFixedPitch(true);
     text_font.setStyleHint(QFont::TypeWriter);
     ui->textEdit->document()->setDefaultFont(text_font);
+    highlighter = new Highlighter(ui->textEdit->document());
 
     connect(ui->actionNew, &QAction::triggered, this, &LammpsGui::new_document);
     connect(ui->actionOpen, &QAction::triggered, this, &LammpsGui::open);
@@ -64,6 +67,7 @@ LammpsGui::LammpsGui(QWidget *parent, const char *filename) :
 LammpsGui::~LammpsGui()
 {
     delete ui;
+    delete highlighter;
 }
 
 void LammpsGui::new_document()

tools/lammps-gui/lammpsgui.h

@@ -17,12 +17,16 @@
 #include <QMainWindow>
 #include <QString>
 
+// forward declarations
+
 QT_BEGIN_NAMESPACE
 namespace Ui {
 class LammpsGui;
 }
 QT_END_NAMESPACE
 
+class Highlighter;
+
 class LammpsGui : public QMainWindow {
     Q_OBJECT
 
@@ -52,6 +56,7 @@ private slots:
 
 private:
     Ui::LammpsGui *ui;
+    Highlighter *highlighter;
 
     QString current_file;
     QString current_dir;