Start work on error handling

src/types.h

@@ -13,7 +13,7 @@ typedef enum GroundInstType {
 } GroundInstType;
 
 typedef enum GroundValueType {
-    INT, DOUBLE, STRING, CHAR, BOOL, LIST, FUNCTION, STRUCTVAL, CUSTOM, NONE
+    INT, DOUBLE, STRING, CHAR, BOOL, LIST, FUNCTION, STRUCTVAL, CUSTOM, ERROR, NONE
 } GroundValueType;
 
 typedef enum GroundArgType {
@@ -29,6 +29,7 @@ struct GroundFunction;
 struct GroundScope;
 struct GroundStruct;
 struct GroundObject;
+struct GroundInstruction;
 
 struct List;
 
@@ -42,6 +43,16 @@ typedef struct List {
     struct GroundValue* values;
 } List;
 
+/*
+ * Stores data associated with an error thrown during Ground execution.
+ */
+typedef struct GroundError {
+    char* what;
+    char* type;
+    struct GroundInstruction* where;
+    size_t line;
+} GroundError;
+
 /*
  * Stores literal values created in a Ground program.
  * Associated functions:
@@ -57,6 +68,7 @@ typedef struct GroundValue {
         char charVal;
         bool boolVal;
         List listVal;
+        GroundError errorVal;
         struct GroundFunction* fnVal;
         struct GroundStruct* structVal;
         struct GroundObject* customVal;
@@ -187,6 +199,9 @@ GroundValue createListGroundValue(List in);
 // Creates a GroundValue conatining (in), with type FUNCTION.
 GroundValue createFunctionGroundValue(GroundFunction* in);
 
+// Creates a GroundValue containing (in), with type ERROR.
+GroundValue createErrorGroundValue(GroundError in);
+
 // Creates a Groundvalue with type NONE.
 GroundValue createNoneGroundValue();
 
@@ -257,4 +272,9 @@ GroundObjectField* findField(GroundObject head, const char *id);
 // Frees a GroundObject
 void freeGroundObject(GroundObject* object);
 
+// Creates a GroundError.
+GroundError createGroundError(char* what, char* type, GroundInstruction* where, size_t* line);
+
+
+
 #endif