Add .get for Tagged type that resolves namespaces.

Author: Grinkers

examples/get-nth.rs

@@ -16,10 +16,26 @@ fn maybe_forty_two<'a>(edn: &'a Edn<'a>) -> Option<&'a Edn<'a>> {
     .nth(2)
 }
 
+fn namespace_get() {
+  // (def edn-data (edn/read-string "#:thingy {:foo \"bar\" :baz/bar \"qux\" 42 24}"))
+  let edn_data = edn::read_string(r#"#:thingy {:foo "bar" :baz/bar "qux" 42 24}"#).unwrap();
+
+  // (get edn-data 42)          -> 24
+  assert_eq!(edn_data.get(&Edn::Int(42)), Some(&Edn::Int(24)));
+  // (get edn-data :foo)        -> nil
+  assert_eq!(edn_data.get(&Edn::Key("foo")), None);
+  // (get edn-data :thingy/foo) -> "bar"
+  assert_eq!(edn_data.get(&Edn::Key("thingy/foo")), Some(&Edn::Str("bar")));
+  // (get edn-data :baz/bar)    -> "qux"
+  assert_eq!(edn_data.get(&Edn::Key("baz/bar")), Some(&Edn::Str("qux")));
+}
+
 fn main() {
   let e = edn::read_string("{:foo {猫 {{:foo :bar} [1 2 42 3]}}}").unwrap();
   let edn = maybe_forty_two(&e).unwrap();
   assert_eq!(edn, &Edn::Int(42));
+
+  namespace_get();
 }
 
 #[test]

src/edn.rs

@@ -80,6 +80,36 @@ impl Edn<'_> {
       if let Some(l) = m.get(e) {
         return Some(l);
       }
+    } else if let Edn::Tagged(tag, m) = self {
+      if let Edn::Key(e) = e {
+        // Break out early if there's no namespaces
+        if !e.contains('/') {
+          return None;
+        }
+
+        // ignore the leading ':'
+        if !tag.starts_with(':') {
+          return None;
+        }
+        let tag = tag.get(1..)?;
+
+        // check if the Key starts with the saved Tag
+        if e.starts_with(tag) {
+          let (_, key) = e.rsplit_once(tag)?;
+
+          // ensure there's a '/' and strip it
+          if key.chars().nth(0) != Some('/') {
+            return None;
+          }
+          let key = key.get(1..)?;
+
+          return m.get(&Edn::Key(key));
+        }
+        return m.get(&Edn::Key(e));
+      }
+
+      // Cover cases where it's not a keyword
+      return m.get(e);
     }
     None
   }