Start of new ANTLR4 based parser.

Very simple tests pass.

pglablib/CaseChangingCharStream.h

@@ -0,0 +1,83 @@
+#pragma once
+
+#include "antlr4-runtime.h"
+#include <QChar>
+
+/// Helper stream for antlr, the lexer does not need to base case sensitive
+/// this is achieved by changing the case of the chars in LA how ever
+/// when the text of a recognized token is captured the getText function
+/// is used which does no case conversion so the parse will receive the original
+/// case.
+class CaseChangingCharStream: public antlr4::CharStream
+{
+public:
+    CaseChangingCharStream(antlr4::CharStream *stream, bool upper)
+        : stream(stream)
+        , upper(upper)
+    {}
+
+    virtual ~CaseChangingCharStream()
+    {}
+
+    virtual void consume() override
+    {
+        stream->consume();
+    }
+
+    virtual size_t LA(ssize_t i) override
+    {
+        int c = stream->LA(i);
+        if (c <= 0)
+            return c;
+
+        if (upper)
+            return QChar::toUpper(c);
+
+        return QChar::toLower(c);
+    }
+
+    virtual std::string getText(const antlr4::misc::Interval &interval) override
+    {
+        return stream->getText(interval);
+    }
+
+    virtual std::string toString() const override
+    {
+        return stream->toString();
+    }
+
+    virtual ssize_t mark() override
+    {
+        return stream->mark();
+    }
+
+    virtual void release(ssize_t marker) override
+    {
+        stream->release(marker);
+    }
+
+    virtual size_t index() override
+    {
+        return stream->index();
+    }
+
+    virtual void seek(size_t index) override
+    {
+        stream->seek(index);
+    }
+
+    virtual size_t size() override
+    {
+        return stream->size();
+    }
+
+    virtual std::string getSourceName() const  override
+    {
+        return stream->getSourceName();
+    }
+
+private:
+    antlr4::CharStream *stream;
+    bool upper;
+
+};