Tweaked the stream classes, added an example, and the begining of a formula

parser.

1 files changed, 62 insertions, 0 deletions

diff --git a/src/formula.h b/src/formula.h
new file mode 100644
index 0000000..1eccd36
--- /dev/null
+++ b/src/formula.h
@@ -0,0 +1,62 @@
+#ifndef FORMULA_H
+#define FORMULA_H
+
+#include <stdint.h>
+
+#include <stack>
+#include "sbuffer.h"
+
+#include "exceptionbase.h"
+
+subExceptionDecl( ParseException );
+
+/**
+ *
+ */
+class Formula
+{
+public:
+        Formula();
+        virtual ~Formula();
+
+        double run( const char *sFormula );
+
+private:
+        enum
+        {
+                symEOS,
+                symAdd,
+                symSubtract,
+                symMultiply,
+                symDivide,
+                symOpenParen,
+                symCloseParen,
+                symNumber,
+                symVariable
+        };
+
+        typedef struct Token
+        {
+                Token() {}
+                Token( uint8_t nSym ) : nSym( nSym ) { }
+                Token( uint8_t nSym, double dNum ) : nSym( nSym ) { val.num = dNum; }
+                uint8_t nSym;
+                union 
+                {
+                        double num;
+                } val;
+        } Token;
+
+        std::stack<Token> sToken;
+        Token tLook;
+        int nState;
+        SBuffer sBuf;
+
+private:
+        void push();
+        void state();
+        Token nextToken();
+        void printToken( Token &tok );
+};
+
+#endif