From 1ee5f374ed986333d5cdbbf41390f1c4c755a8e3 Mon Sep 17 00:00:00 2001
From: Mike Buland <eichlan@xagasoft.com>
Date: Tue, 12 Oct 2010 06:09:48 +0000
Subject: This commit has a minor tweak to the variant class to make it easier
 to use, and introduces the parser and lexer classes.  I also made a test for
 parser and put it in the tools directory.  That is silly, it shouldn't be. 
 However, it's necesarry right now, because I don't want to do a full build to
 compile all the parser tests.

However, this commit doesn't actually build yet.  It will soon, I just wanted
to get it all committed.
---
 src/tools/parser.cpp | 164 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)
 create mode 100644 src/tools/parser.cpp

(limited to 'src/tools')

diff --git a/src/tools/parser.cpp b/src/tools/parser.cpp
new file mode 100644
index 0000000..a70dfa4
--- /dev/null
+++ b/src/tools/parser.cpp
@@ -0,0 +1,164 @@
+#include <bu/parser.h>
+#include <bu/lexer.h>
+#include <bu/file.h>
+#include <bu/sio.h>
+#include <bu/queuebuf.h>
+#include <stdlib.h>
+
+using namespace Bu;
+
+enum Tok
+{
+	tokNumber,
+	tokPlus,
+	tokMinus,
+	tokDivide,
+	tokMultiply,
+	tokOpenParen,
+	tokCloseParen,
+	tokCompute,
+	tokEndOfInput=-1
+};
+
+Bu::Formatter &operator<<( Bu::Formatter &f, Tok e )
+{
+	switch( e )
+	{
+		case tokNumber: return f << "tokNumber";
+		case tokPlus: return f << "tokPlus";
+		case tokMinus: return f << "tokMinus";
+		case tokDivide: return f << "tokDivide";
+		case tokMultiply: return f << "tokMultiply";
+		case tokOpenParen: return f << "tokOpenParen";
+		case tokCloseParen: return f << "tokCloseParen";
+		case tokCompute: return f << "tokCompute";
+		case tokEndOfInput: return f << "tokEndOfInput";
+	}
+
+	return f << "***error***";
+}
+
+class MathLexer : public Lexer
+{
+public:
+	MathLexer( Bu::Stream &rSrc ) :
+		rSrc( rSrc )
+	{
+	}
+
+	virtual ~MathLexer()
+	{
+	}
+
+	enum TokenTypes
+	{
+		tokStuff
+	};
+
+	virtual Token *nextToken()
+	{
+		for(;;)
+		{
+			if( qbIn.getSize() == 0 )
+			{
+				char buf[4096];
+				qbIn.write( buf, rSrc.read( buf, 4096 ) );
+
+				if( rSrc.isEos() && qbIn.getSize() == 0 )
+					return new Token( tokEndOfInput );
+			}
+
+			char b;
+			qbIn.peek( &b, 1 );
+			switch( b )
+			{
+				case '+':
+					qbIn.seek( 1 );
+					return new Token( tokPlus );
+
+				case '-':
+					qbIn.seek( 1 );
+					return new Token( tokMinus );
+
+				case '/':
+					qbIn.seek( 1 );
+					return new Token( tokDivide );
+
+				case '*':
+					qbIn.seek( 1 );
+					return new Token( tokMultiply );
+
+				case ' ':
+				case '\t':
+				case '\n':
+					qbIn.seek( 1 );
+					break;
+
+				case '=':
+					qbIn.seek( 1 );
+					return new Token( tokCompute );
+
+				case '(':
+					qbIn.seek( 1 );
+					return new Token( tokOpenParen );
+
+				case ')':
+					qbIn.seek( 1 );
+					return new Token( tokCloseParen );
+
+				case '.':
+				case '0':
+				case '1':
+				case '2':
+				case '3':
+				case '4':
+				case '5':
+				case '6':
+				case '7':
+				case '8':
+				case '9':
+					{
+						Bu::FString sTmp;
+						sTmp += b;
+						qbIn.seek( 1 );
+						for(;;)
+						{
+							qbIn.peek( &b, 1 );
+							if( b != '.' && (b < '0' || b > '9') )
+							{
+								sio << "!! Convert '" << sTmp << "' to "
+									<< strtod( sTmp.getStr(), NULL ) << sio.nl;
+								return new Token(
+									tokNumber, strtod( sTmp.getStr(), NULL )
+									);
+							}
+							qbIn.seek( 1 );
+							sTmp += b;
+						}
+					}
+					break;
+
+				default:
+					throw Bu::ExceptionBase("Unexpected character '%c'.", b );
+			}
+		}
+	}
+
+private:
+	Bu::Stream &rSrc;
+	QueueBuf qbIn;
+};
+
+int main( int argc, char *argv[] )
+{
+	File fIn( argv[1], File::Read );
+
+	Parser p;
+
+	p.pushLexer( new MathLexer( fIn ) );
+
+	p.parse();
+
+	return 0;
+}
+
-- 
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