Python Editor Syntax Highlighter

.. basic stuff for now.

src/Python/PythonSyntax.cpp

@@ -0,0 +1,151 @@
+/*
+ * 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 "PythonSyntax.h"
+
+
+PythonSyntax::PythonSyntax(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" << "\\bNone\\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  << "\\bas\\b" << "\\bassert\\b" << "\\bbreak\\b"
+                     << "\\bclass\\b" << "\\bcontinue\\b" << "\\bdel\\b" << "\\belif\\b" << "\\belse\\b"
+                     << "\\bexcept\\b" << "\\bfinally\\b" << "\\bfor\\b" << "\\bfrom\\b" << "\\bglobal\\b" << "\\bif\\b"
+                     << "\\bimport\\b" << "\\bin\\b" << "\\bis\\b" << "\\blambda\\b" << "\\bnonlocal\\b" << "\\bnot\\b"
+                     << "\\bpass\\b" << "\\braise\\b" << "\\breturn\\b" << "\\btry\\b" << "\\bwhile\\b"
+                     << "\\bwith\\b" << "\\byield\\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(40,255,40));
+    QStringList commonFunctionPatterns;
+    commonFunctionPatterns << "\\bdef\\b" << "\\bself\\b";
+    foreach (QString pattern, commonFunctionPatterns) {
+        rule.pattern = QRegExp(pattern);
+        rule.format = commonFunctionFormat;
+        highlightingRules.append(rule);
+    }
+
+    // operators
+    operatorFormat.setForeground(QColor(255,204,000));
+    //operatorFormat.setForeground(Qt::darkCyan);
+    //operatorFormat.setFontWeight(QFont::Bold);
+    QStringList operatorPatterns;
+
+    //operatorPatterns << "[\\&\\$\\@\\|\\:\\~\\{\\}\\(\\)!]" << "==" << "!=";
+    operatorPatterns << "\\band\\b" << "\\bor\\b" << "\\bnot\\b" << "[\\.\\&\\$\\@\\|\\:\\~\\{\\}\\(\\)!]" ;
+
+    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 PythonSyntax::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);
+        }
+    }
+}