Began implementing the befunge field data structure

pkg/field/error.go

@@ -0,0 +1,34 @@
+package field
+
+import "fmt"
+
+// Read error
+type ReadError struct {
+	err error
+}
+
+func (e ReadError) Error() string {
+	return fmt.Sprintf("Failed to decode file")
+}
+func (e ReadError) Unwrap() error { return e.err }
+
+func newReadError(err error) error {
+	return &ReadError{
+		err: err,
+	}
+}
+
+// Funge decoding error
+type DecodeError struct {
+	msg string
+}
+
+func (e DecodeError) Error() string {
+	return fmt.Sprintf("Failed to decode file with message : %s", e.msg)
+}
+
+func newDecodeError(msg string) error {
+	return &DecodeError{
+		msg: msg,
+	}
+}