R Script syntax highlighter

.. basic stuff, no completer.

src/Charts/RChart.cpp

@@ -19,6 +19,7 @@
 #include "R.h"
 #include "RTool.h"
 #include "RChart.h"
+#include "RSyntax.h"
 
 #include "Colors.h"
 #include "TabView.h"
@@ -285,6 +286,9 @@ RChart::RChart(Context *context) : GcChartWindow(context), context(context)
         script->setPalette(p);
         script->setStyleSheet(TabView::ourStyleSheet());
 
+        // syntax highlighter
+        RSyntax syntax(script->document());
+
         leftsplitter->addWidget(script);
         console = new RConsole(context, this);
         leftsplitter->addWidget(console);
@@ -319,7 +323,10 @@ RChart::getScript() const
 void
 RChart::setScript(QString string)
 {
-    if (rtool && script) script->setText(string);
+    if (rtool && script) {
+        script->setText(string);
+        new RSyntax(script->document());
+    }
     text = string;
 }
 

src/R/RSyntax.cpp

@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2016 Mark Liversedge (liversedge@gmail.com)
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <QSyntaxHighlighter>
+
+#include "RSyntax.h"
+
+
+RSyntax::RSyntax(QTextDocument *parent) : QSyntaxHighlighter(parent)
+{
+    HighlightingRule rule;
+
+    assignmentFormat.setForeground(QColor(255,204,000));
+    rule.pattern = QRegExp("<{1,2}[-]");
+    rule.format = assignmentFormat;
+    highlightingRules.append(rule);
+    rule.pattern = QRegExp("[-]>{1,2}");
+    rule.format = assignmentFormat;
+    highlightingRules.append(rule);
+
+
+    // function: anything followed by (
+    functionFormat.setForeground(Qt::cyan);
+    //functionFormat.setFontItalic(true);
+    rule.pattern = QRegExp("\\b[A-Za-z0-9_\\.]+(?=[ ]*\\()");
+    rule.format = functionFormat;
+    highlightingRules.append(rule);
+
+    // argument: anything followed by =, but not at the start(???)
+    // unfortunately look behind assertions are not supported
+    argumentFormat.setFontItalic(true);
+    rule.pattern = QRegExp("[A-Za-z0-9_\\.]+(?=[ ]*=[^=])");
+    rule.format = argumentFormat;
+    highlightingRules.append(rule);
+
+    // numbers
+    numberFormat.setForeground(Qt::red);
+    QStringList numberPatterns;
+    numberPatterns << "\\b[0-9]+[\\.]?[0-9]*\\b"  << "\\b[\\.][0-9]+\\b";
+    foreach (QString pattern, numberPatterns) {
+        rule.pattern = QRegExp(pattern);
+        rule.format = numberFormat;
+        highlightingRules.append(rule);
+    }
+
+    // constants: TRUE FALSE NA NULL Inf NaN
+    constantFormat.setForeground(Qt::red);
+    QStringList constantPatterns;
+    constantPatterns << "\\bTRUE\\b" << "\\bFALSE\\b" << "\\bNA\\b"  << "\\bNULL\\b" << "\\bInf\\b" << "\\bNaN\\b";
+    foreach (QString pattern, constantPatterns) {
+        rule.pattern = QRegExp(pattern);
+        rule.format = constantFormat;
+        highlightingRules.append(rule);
+    }
+
+    // keywords: while for in repeat if else switch break next
+    // function return message warning stop
+    keywordFormat.setForeground(QColor(255,204,000));
+    //keywordFormat.setFontItalic(true);
+    QStringList keywordPatterns;
+    keywordPatterns << "\\bwhile\\b" << "\\bfor\\b" << "\\bin([^%]?)\\b" 
+            << "\\brepeat\\b" << "\\bif\\b" << "\\belse\\b" 
+            << "\\bswitch\\b" << "\\bbreak\\b" << "\\bnext\\b" 
+            << "\\bfunction\\b" << "\\breturn\\b" << "\\bmessage\\b" 
+            << "\\bwarning\\b" << "\\bstop\\b";
+    foreach (QString pattern, keywordPatterns) {
+        rule.pattern = QRegExp(pattern);
+        rule.format = keywordFormat;
+        highlightingRules.append(rule);
+    }
+
+    // common functions (says who? (I hate attach)): library attach
+    // detach source require
+    commonFunctionFormat.setForeground(QColor(255,204,000));
+    QStringList commonFunctionPatterns;
+    commonFunctionPatterns << "\\blibrary\\b" << "\\bsource\\b" << "\\brequire\\b";
+    foreach (QString pattern, commonFunctionPatterns) {
+        rule.pattern = QRegExp(pattern);
+        rule.format = commonFunctionFormat;
+        highlightingRules.append(rule);
+    }
+
+    // operators
+    //operatorFormat.setForeground(Qt::darkCyan);
+    //operatorFormat.setFontWeight(QFont::Bold);
+    //QStringList operatorPatterns;
+
+    //operatorPatterns << "[\\&\\$\\@\\|\\:\\~\\{\\}\\(\\)!]" << "==" << "!=";
+
+    //foreach (QString pattern, operatorPatterns) {
+    //rule.pattern = QRegExp(pattern);
+    //rule.format = operatorFormat;
+    //highlightingRules.append(rule);
+    //}
+
+    // namespace: anything followed by ::
+    //namespaceFormat.setForeground(Qt::magenta);
+    //rule.pattern = QRegExp("\\b[A-Za-z0-9_\\.]+(?=::)");
+    //rule.format = namespaceFormat;
+    //highlightingRules.append(rule);
+
+    // quotes: only activated after quotes are closed.  Does not
+    // span lines.
+    quotationFormat.setForeground(Qt::red);
+    rule.pattern = QRegExp("\"[^\"]*\"");
+    rule.format = quotationFormat;
+    highlightingRules.append(rule);
+    rule.pattern = QRegExp("'[^']*\'");
+    rule.format = quotationFormat;
+    highlightingRules.append(rule);
+
+    // comments (should override everything else)
+    commentFormat.setForeground(QColor(100,149,237));
+    rule.pattern = QRegExp("#[^\n]*");
+    rule.format = commentFormat;
+    highlightingRules.append(rule);
+}
+
+
+void RSyntax::highlightBlock(const QString &text)
+{
+    foreach (HighlightingRule rule, highlightingRules) {
+        QRegExp expression(rule.pattern);
+        int index = text.indexOf(expression);
+        // NB: this is index in block, not full document
+        while (index >= 0) {
+            int length = expression.matchedLength();
+            setFormat(index, length, rule.format);
+            index = text.indexOf(expression, index + length);
+        }
+    }
+}

src/R/RSyntax.h

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2016 Mark Liversedge (liversedge@gmail.com)
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef GC_RSyntax
+#define GC_RSyntax
+
+#include <QSyntaxHighlighter>
+
+#include <QHash>
+#include <QTextCharFormat>
+
+class QTextDocument;
+
+class RSyntax : public QSyntaxHighlighter
+{
+    Q_OBJECT
+
+ public:
+    RSyntax(QTextDocument *parent = 0);
+
+ protected:
+    void highlightBlock(const QString &text);
+
+ private:
+    struct HighlightingRule {
+        QRegExp pattern;
+        QTextCharFormat format;
+    };
+    QVector<HighlightingRule> highlightingRules;
+
+    // initial classifications and values borrowed from ESS
+    QTextCharFormat assignmentFormat;
+    QTextCharFormat functionFormat;
+    QTextCharFormat numberFormat;
+    QTextCharFormat argumentFormat;
+    QTextCharFormat constantFormat;
+    QTextCharFormat keywordFormat;
+    QTextCharFormat commonFunctionFormat;
+    QTextCharFormat operatorFormat;
+    QTextCharFormat namespaceFormat;
+    QTextCharFormat commentFormat;
+    QTextCharFormat quotationFormat;
+};
+
+#endif

src/src.pro

@@ -262,8 +262,8 @@ contains(DEFINES, "GC_WANT_R") {
     DEFINES += STRICT_R_HEADERS
 
     ## R integration
-    HEADERS += R/REmbed.h R/RTool.h R/RGraphicsDevice.h
-    SOURCES += R/REmbed.cpp R/RTool.cpp R/RGraphicsDevice.cpp
+    HEADERS += R/REmbed.h R/RTool.h R/RGraphicsDevice.h R/RSyntax.h
+    SOURCES += R/REmbed.cpp R/RTool.cpp R/RGraphicsDevice.cpp R/RSyntax.cpp
 
     ## R based charts
     HEADERS += Charts/RChart.h Charts/RCanvas.h