Add utilities to enum (#44)

* Add utilities to enum

* Fix unexpected pyo3 dependency propagation

core/src/format.rs

@@ -11,3 +11,15 @@ pub enum ConversionFlag {
     /// Converts by calling `repr(<value>)`.
     Repr = b'r' as i8,
 }
+
+impl ConversionFlag {
+    pub fn to_byte(&self) -> Option<u8> {
+        match self {
+            Self::None => None,
+            flag => Some(*flag as u8),
+        }
+    }
+    pub fn to_char(&self) -> Option<char> {
+        Some(self.to_byte()? as char)
+    }
+}

core/src/mode.rs

@@ -1,7 +1,7 @@
 //! Control in the different modes by which a source file can be parsed.
 
 /// The mode argument specifies in what way code must be parsed.
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Hash, PartialEq, Eq)]
 pub enum Mode {
     /// The code consists of a sequence of statements.
     Module,