From 00ecd458ced768b3b8752cdd421a22244b7adc01 Mon Sep 17 00:00:00 2001
From: Mike Buland <eichlan@xagasoft.com>
Date: Sun, 17 Oct 2010 05:50:57 +0000
Subject: Hey!  The parser parses now!  It's actually a little stupid, I didn't
 implement lookahead or precedence, but I should be able to do that easily
 with the next version.  I'm treating this more as a proof of concept than a
 real working model.  Although it can handle +, -, (), and = :)

---
 src/parser.cpp | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

(limited to 'src/parser.cpp')

diff --git a/src/parser.cpp b/src/parser.cpp
index e4e8ae5..3ce73b6 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -22,16 +22,25 @@ void Bu::Parser::popLexer()
 	delete sLexer.peekPop();
 }
 
+Lexer::Token *Bu::Parser::popToken()
+{
+	return sToken.peekPop();
+}
+
+void Bu::Parser::pushToken( Lexer::Token *pTok )
+{
+	sToken.push( pTok );
+}
+
 void Bu::Parser::parse()
 {
 	int iCurNt = iRootNonTerminal;
 	Lexer::Token *ptCur = sLexer.peek()->nextToken();
-	sio << "Token: " << sLexer.peek()->tokenToString( *ptCur ) << sio.nl;
+	sio << "Token(a): " << sLexer.peek()->tokenToString( *ptCur ) << sio.nl;
 	selectProduction( iCurNt, ptCur );
 	
 	while( !sState.isEmpty() )
 	{
-		sio << "Currently: " << *sState.peek() << sio.nl;
 		switch( (*sState.peek()).eType )
 		{
 			case State::typeTerminal:
@@ -42,7 +51,7 @@ void Bu::Parser::parse()
 					advanceState();
 					delete ptCur;
 					ptCur = sLexer.peek()->nextToken();
-					sio << "Token: " << sLexer.peek()->tokenToString( *ptCur ) << sio.nl;
+					sio << "Token(b): " << sLexer.peek()->tokenToString( *ptCur ) << sio.nl;
 				}
 				else
 				{
@@ -59,7 +68,7 @@ void Bu::Parser::parse()
 					sToken.push( ptCur );
 
 					ptCur = sLexer.peek()->nextToken();
-					sio << "Token: " << sLexer.peek()->tokenToString( *ptCur ) << sio.nl;
+					sio << "Token(c): " << sLexer.peek()->tokenToString( *ptCur ) << sio.nl;
 				}
 				else
 				{
@@ -72,7 +81,7 @@ void Bu::Parser::parse()
 					<< (*sState.peek()).iIndex << sio.nl;
 				{
 					int iNt = (*sState.peek()).iIndex;
-					advanceState();
+					sio << "Current state: " << *sState.peek() << sio.nl;
 					if( !selectProduction( iNt, ptCur ) )
 					{
 						throw Bu::ExceptionBase("Error parsing code.");
@@ -132,7 +141,11 @@ bool Bu::Parser::selectProduction( int iNt, Lexer::Token *ptCur )
 		}
 	}
 	if( nt.bCanSkip )
+	{
+		sio << "Nothing matches, skipping non-terminal." << sio.nl;
+		advanceState();
 		return true;
+	}
 	sio << "-->(Found nothing)" << sio.nl;
 	return false;
 }
@@ -148,6 +161,7 @@ void Bu::Parser::advanceState()
 		sio.decIndent();
 		sState.pop();
 		sio << "State advanced, End of production." << sio.nl;
+		advanceState();
 		return;
 	}
 	sio << "State advanced, now: " << *(sState.peek()) << sio.nl;
-- 
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