diff --git a/include/groundext.h b/include/groundext.h
index e8c35ac..735b9b7 100644
--- a/include/groundext.h
+++ b/include/groundext.h
@@ -7,10 +7,30 @@
 extern "C" {
 #endif
 
+// Macro for easily returning errors
+#define ERROR(what, type) return createErrorGroundValue(createGroundError(what, type, NULL, NULL))
+
 // Forward declaration of the scope structure used in interpreter
 struct GroundScope;
 typedef struct GroundScope GroundScope;
 
+/*
+ * Stores data associated with an error thrown during Ground execution.
+ */
+typedef struct GroundError {
+    char* what;
+    char* type;
+    struct GroundInstruction* where;
+    size_t line;
+    bool hasLine;
+} GroundError;
+
+// Creates a GroundValue containing (in), with type ERROR.
+GroundValue createErrorGroundValue(GroundError in);
+
+// Creates a GroundError.
+GroundError createGroundError(char* what, char* type, GroundInstruction* where, size_t* line);
+
 /*
  * Function pointer type for native functions.
  * scope: The current execution scope (opaque).