From 469bbcf0701e1eb8a6670c23145b0da87357e178 Mon Sep 17 00:00:00 2001
From: Mike Buland <eichlan@xagasoft.com>
Date: Sun, 25 Mar 2012 20:00:08 +0000
Subject: Code is all reorganized.  We're about ready to release.  I should
 write up a little explenation of the arrangement.

---
 src/experimental/parser.h | 135 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 src/experimental/parser.h

(limited to 'src/experimental/parser.h')

diff --git a/src/experimental/parser.h b/src/experimental/parser.h
new file mode 100644
index 0000000..a168c7b
--- /dev/null
+++ b/src/experimental/parser.h
@@ -0,0 +1,135 @@
+/*
+ * Copyright (C) 2007-2011 Xagasoft, All rights reserved.
+ *
+ * This file is part of the libbu++ library and is released under the
+ * terms of the license contained in the file LICENSE.
+ */
+
+#ifndef BU_PARSER_H
+#define BU_PARSER_H
+
+#include "bu/string.h"
+#include "bu/list.h"
+#include "bu/array.h"
+#include "bu/hash.h"
+#include "bu/signals.h"
+
+#include "bu/lexer.h"
+
+namespace Bu
+{
+	/**
+	 * The base framework for a LR(1) grammar parser.  Provided a proper set of
+	 * ParserStates this will prase any input the lexer can provide.
+	 */
+	class Parser
+	{
+	public:
+		Parser();
+		virtual ~Parser();
+
+		/**
+		 * When a Lexer is pushed onto the stack it becomes the source for
+		 * future tokens read by the parser until it is popped off the stack.
+		 * The Parser takes ownership of every Lexer pushed onto the stack,
+		 * and will delete it when it is popped off the stack.
+		 */
+		void pushLexer( Lexer *pLex );
+
+		/**
+		 * Pop a lexer off the stack, and delete it.
+		 */
+		void popLexer();
+
+		Lexer::Token *popToken();
+		void pushToken( Lexer::Token *pTok );
+
+		/**
+		 * Execute a parse.
+		 */
+		void parse();
+
+		void setRootNonTerminal( int iRoot );
+		void setRootNonTerminal( const Bu::String &sRoot );
+
+		typedef Bu::Signal1<void, Parser &> Reduction;
+
+		/**
+		 * Represents a possible state, either a terminal or non-terminal symbol
+		 * in a Production.
+		 */
+		class State
+		{
+		public:
+			enum Type
+			{
+				typeTerminal,
+				typeTerminalPush,
+				typeNonTerminal,
+				typeReduction
+			};
+
+			State( Type eType, int iIndex );
+			virtual ~State();
+
+		//private:
+			Type eType;
+			int iIndex;
+		};
+
+		typedef Bu::List<State> Production;
+
+		class NonTerminal
+		{
+		public:
+			NonTerminal();
+			virtual ~NonTerminal();
+
+			void addProduction( Production p );
+			void setCanSkip();
+
+//		private:
+			typedef Bu::List<Production> ProductionList;
+			ProductionList lProduction;
+			bool bCanSkip;
+		};
+
+		int addNonTerminal( const Bu::String &sName, NonTerminal &nt );
+		int addNonTerminal( const Bu::String &sName );
+		void setNonTerminal( const Bu::String &sName, NonTerminal &nt );
+		int getNonTerminalId( const Bu::String &sName );
+		bool hasNonTerminal( const Bu::String &sName );
+
+		int addReduction( const Bu::String &sName, const Reduction &r );
+		int addReduction( const Bu::String &sName );
+		void setReduction( const Bu::String &sName, const Reduction &r );
+		int getReductionId( const Bu::String &sName );
+		bool hasReduction( const Bu::String &sName );
+
+	private:
+		bool selectProduction( int iNt, Lexer::Token *ptCur );
+		void advanceState();
+
+	private:
+		typedef Bu::List<Lexer *> LexerStack;
+		typedef Bu::List<Lexer::Token *> TokenStack;
+		typedef Bu::List<Production::const_iterator> StateStack;
+		typedef Bu::Array<Reduction> ReductionArray;
+		typedef Bu::Hash<Bu::String,int> NameIndexHash;
+		typedef Bu::Array<NonTerminal> NonTerminalArray;
+
+		LexerStack sLexer;
+		TokenStack sToken;
+		StateStack sState;
+		ReductionArray aReduction;
+		NameIndexHash hReductionName;
+		NonTerminalArray aNonTerminal;
+		NameIndexHash hNonTerminalName;
+		int iRootNonTerminal;
+	};
+Bu::Formatter &operator<<( Bu::Formatter &f, Bu::Parser::State::Type t );
+Bu::Formatter &operator<<( Bu::Formatter &f, const Bu::Parser::State &s );
+};
+
+
+#endif
-- 
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