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.

1 files changed, 164 insertions, 0 deletions

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;
+}
+