changed subtypes for tags

headers/lexer.h

@@ -139,35 +139,72 @@
  * PROPOSITION 3
  */
 
+// typedef enum
+// {
+//     TOKEN_VARIABLE, // x, y, etc.
+//     TOKEN_NUMBER,   // int or double
+//     TOKEN_POWER,    // ^ or **
+//     TOKEN_SIGN,     // + or -
+//     TOKEN_FACTOR,   // * or / or :
+//     TOKEN_EQUAL,    // =
+//     TOKEN_END       // null (end of input)
+// } token_type;
+//
+// typedef enum
+// {
+//     TOKEN_NO_SUBTYPE,
+//     // NUMBER
+//     TOKEN_NUMBER_INT,
+//     TOKEN_NUMBER_DOUBLE,
+//     // SIGN
+//     TOKEN_SIGN_PLUS,
+//     TOKEN_SIGN_MINUS,
+//     // FACTOR
+//     TOKEN_FACTOR_MULTIPLICATION,
+//     TOKEN_FACTOR_DIVISION,
+// } token_subtype;
+//
+// typedef struct
+// {
+//     token_type type;
+//     token_subtype subtype;
+//     union
+//     {
+//         char value_char;
+//         double value_double;
+//     };
+// } token;
+
+/**
+ * PROPOSITION 4
+ */
+
 typedef enum
 {
-    TOKEN_VARIABLE, // x, y, etc.
-    TOKEN_NUMBER,   // int or double
-    TOKEN_POWER,    // ^ or **
-    TOKEN_SIGN,     // + or -
-    TOKEN_FACTOR,   // * or / or :
-    TOKEN_EQUAL,    // =
-    TOKEN_END       // null (end of input)
+    TOKEN_VARIABLE,      // x, y, etc.
+    TOKEN_NUMBER_INT,    // int
+    TOKEN_NUMBER_DOUBLE, // double
+    TOKEN_POWER,         // ^ or **
+    TOKEN_SIGN_PLUS,     // +
+    TOKEN_SIGN_MINUS,    // -
+    TOKEN_FACTOR_MULT,   // *
+    TOKEN_FACTOR_DIV,    // / or :
+    TOKEN_EQUAL,         // =
+    TOKEN_END            // null (end of input)
 } token_type;
 
 typedef enum
 {
-    TOKEN_NO_SUBTYPE,
-    // NUMBER
-    TOKEN_NUMBER_INT,
-    TOKEN_NUMBER_DOUBLE,
-    // SIGN
-    TOKEN_SIGN_PLUS,
-    TOKEN_SIGN_MINUS,
-    // FACTOR
-    TOKEN_FACTOR_MULTIPLICATION,
-    TOKEN_FACTOR_DIVISION,
-} token_subtype;
+    TOKEN_NO_TAG,
+    TOKEN_NUMBER,
+    TOKEN_SIGN,
+    TOKEN_FACTOR,
+} token_tag;
 
 typedef struct
 {
     token_type type;
-    token_subtype subtype;
+    token_tag tag;
     union
     {
         char value_char;