Start of new ANTLR4 based parser.

Very simple tests pass.

pglablib/sqlparser/ErrorListener.cpp

@@ -0,0 +1,22 @@
+#include "ErrorListener.h"
+
+
+void ErrorListener::syntaxError(antlr4::Recognizer *recognizer, antlr4::Token *offendingSymbol, size_t line, size_t charPositionInLine, const std::string &msg, std::exception_ptr e)
+{
+    ++errors;
+}
+
+void ErrorListener::reportAmbiguity(antlr4::Parser *recognizer, const antlr4::dfa::DFA &dfa, size_t startIndex, size_t stopIndex, bool exact, const antlrcpp::BitSet &ambigAlts, antlr4::atn::ATNConfigSet *configs)
+{
+    ++errors;
+}
+
+void ErrorListener::reportAttemptingFullContext(antlr4::Parser *recognizer, const antlr4::dfa::DFA &dfa, size_t startIndex, size_t stopIndex, const antlrcpp::BitSet &conflictingAlts, antlr4::atn::ATNConfigSet *configs)
+{
+    ++errors;
+}
+
+void ErrorListener::reportContextSensitivity(antlr4::Parser *recognizer, const antlr4::dfa::DFA &dfa, size_t startIndex, size_t stopIndex, size_t prediction, antlr4::atn::ATNConfigSet *configs)
+{
+    ++errors;
+}

pglablib/sqlparser/ErrorListener.h

@@ -0,0 +1,21 @@
+#pragma once
+#include "antlr4-runtime.h"
+
+class ErrorListener : public antlr4::ANTLRErrorListener
+{
+    // ANTLRErrorListener interface
+public:
+    virtual void syntaxError(antlr4::Recognizer *recognizer, antlr4::Token *offendingSymbol, size_t line, size_t charPositionInLine, const std::string &msg, std::exception_ptr e) override;
+    virtual void reportAmbiguity(antlr4::Parser *recognizer, const antlr4::dfa::DFA &dfa, size_t startIndex, size_t stopIndex, bool exact, const antlrcpp::BitSet &ambigAlts, antlr4::atn::ATNConfigSet *configs) override;
+    virtual void reportAttemptingFullContext(antlr4::Parser *recognizer, const antlr4::dfa::DFA &dfa, size_t startIndex, size_t stopIndex, const antlrcpp::BitSet &conflictingAlts, antlr4::atn::ATNConfigSet *configs) override;
+    virtual void reportContextSensitivity(antlr4::Parser *recognizer, const antlr4::dfa::DFA &dfa, size_t startIndex, size_t stopIndex, size_t prediction, antlr4::atn::ATNConfigSet *configs) override;
+
+public:
+    int errorCount() const
+    {
+        return errors;
+    }
+
+private:
+    int errors = 0;
+};

pglablib/sqlparser/Parser.cpp

@@ -0,0 +1,21 @@
+#include "Parser.h"
+#include "antlr4-runtime.h"
+
+
+Parser::Parser(const std::string &input_string)
+    : InputStream(std::make_unique<antlr4::ANTLRInputStream>(input_string))
+    , CaseFilter(InputStream.get(), true)
+    , Lexer(&CaseFilter)
+    , TokenStream(&Lexer)
+    , AParser(&TokenStream)
+{
+    AParser.removeErrorListeners();
+    AParser.addErrorListener(&Errors);
+}
+
+std::unique_ptr<sqlast::StatementList> Parser::Parse()
+{
+    auto context = AParser.main();
+    return std::move(context->program);
+}
+

pglablib/sqlparser/Parser.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include ".generated/PgsqlLexer.h"
+#include ".generated/PgsqlParser.h"
+#include "CaseChangingCharStream.h"
+#include "ErrorListener.h"
+
+class Parser
+{
+public:
+    Parser(const std::string &input_string);
+
+    std::unique_ptr<sqlast::StatementList> Parse();
+
+    int errorCount() const
+    {
+        return Errors.errorCount();
+    }
+private:
+    std::unique_ptr<antlr4::CharStream> InputStream;
+    CaseChangingCharStream CaseFilter;
+    PgsqlLexer Lexer;
+    antlr4::CommonTokenStream TokenStream;
+    PgsqlParser AParser;
+    ErrorListener Errors;
+};
+