added exception facilities

1 files changed, 37 insertions, 0 deletions

diff --git a/exc.h b/exc.h
new file mode 100644
index 0000000..7a6879d
--- /dev/null
+++ b/exc.h
@@ -0,0 +1,37 @@
+#ifndef EXC_H
+#define EXC_H
+
+#include "consts.h"
+#include <string>
+
+using std::string;
+
+/** @class GeneralError
+ * The top-level exception
+ */
+class GeneralError {
+    public:
+        virtual string get_msg() = 0;   /**< Extract error message */
+};
+
+class SyntaxError : public GeneralError {
+    protected:
+        string msg;                     /**< Error mesg */
+        ErrCode code;                   /**< Error code */
+    public:
+
+        SyntaxError(ErrCode code);          /**< Construct an SyntaxError */ 
+        string get_msg();                   /**< Get the error message */
+};
+
+class TokenError : public SyntaxError {
+    public:
+        TokenError(string token, ErrCode code);     /**< Construct an TokenError */
+};
+
+class NormalError : public SyntaxError {
+    public:
+        NormalError(ErrCode code);
+};
+
+#endif