some changes to rustical_xml

crates/xml/src/value.rs

@@ -0,0 +1,33 @@
+use std::convert::Infallible;
+use std::num::ParseIntError;
+use std::str::FromStr;
+use thiserror::Error;
+
+use crate::XmlDeError;
+
+#[derive(Debug, Error)]
+pub enum ParseValueError {
+    #[error(transparent)]
+    Infallible(#[from] Infallible),
+    #[error(transparent)]
+    ParseIntError(#[from] ParseIntError),
+}
+
+pub trait Value: Sized {
+    fn serialize(&self) -> String;
+    fn deserialize(val: &str) -> Result<Self, XmlDeError>;
+}
+
+impl<E, T: FromStr<Err = E> + ToString> Value for T
+where
+    ParseValueError: From<E>,
+{
+    fn serialize(&self) -> String {
+        self.to_string()
+    }
+    fn deserialize(val: &str) -> Result<Self, XmlDeError> {
+        val.parse()
+            .map_err(ParseValueError::from)
+            .map_err(XmlDeError::from)
+    }
+}