1 files changed, 34 insertions, 0 deletions
diff --git a/dhall/src/syntax/core/label.rs b/dhall/src/syntax/core/label.rs
new file mode 100644
index 0000000..43c3f53
--- /dev/null
+++ b/dhall/src/syntax/core/label.rs
@@ -0,0 +1,34 @@
+use std::rc::Rc;
+
+// The type for labels throughout the AST
+// It owns the data because otherwise lifetimes would make recursive imports impossible
+#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct Label(Rc<str>);
+
+impl From<String> for Label {
+    fn from(s: String) -> Self {
+        let s: &str = &s;
+        Label(s.into())
+    }
+}
+
+impl<'a> From<&'a str> for Label {
+    fn from(s: &'a str) -> Self {
+        Label(Rc::from(s))
+    }
+}
+
+impl From<&Label> for String {
+    fn from(x: &Label) -> String {
+        x.0.as_ref().to_owned()
+    }
+}
+
+impl Label {
+    pub fn from_str(s: &str) -> Label {
+        Label(s.into())
+    }
+    pub fn as_ref(&self) -> &str {
+        self.0.as_ref()
+    }
+}