1 files changed, 61 insertions, 0 deletions
diff --git a/vendor/elsa/examples/string_interner.rs b/vendor/elsa/examples/string_interner.rs
new file mode 100644
index 000000000..fd039f7ba
--- /dev/null
+++ b/vendor/elsa/examples/string_interner.rs
@@ -0,0 +1,61 @@
+use std::collections::BTreeSet;
+use std::convert::AsRef;
+
+use elsa::FrozenIndexSet;
+
+struct StringInterner {
+    set: FrozenIndexSet<String>,
+}
+
+impl StringInterner {
+    fn new() -> Self {
+        StringInterner {
+            set: FrozenIndexSet::new(),
+        }
+    }
+
+    fn get_or_intern<T>(&self, value: T) -> usize
+    where
+        T: AsRef<str>,
+    {
+        // TODO use Entry in case the standard Entry API gets improved
+        // (here to avoid premature allocation or double lookup)
+        self.set.insert_full(value.as_ref().to_string()).0
+    }
+
+    fn get<T>(&self, value: T) -> Option<usize>
+    where
+        T: AsRef<str>,
+    {
+        self.set.get_full(value.as_ref()).map(|(i, _r)| i)
+    }
+
+    fn resolve(&self, index: usize) -> Option<&str> {
+        self.set.get_index(index)
+    }
+}
+
+fn main() {
+    let interner = StringInterner::new();
+    let lonely = interner.get_or_intern("lonely");
+    let best_friend = interner.get_or_intern("best friend");
+    let threes_a_crowd = interner.get_or_intern("threes a crowd");
+    let rando = interner.get_or_intern("rando");
+    let _facebook = interner.get_or_intern("facebook");
+
+    let best_friend_2 = interner.get_or_intern("best friend");
+    let best_friend_3 = interner.get("best friend").unwrap();
+
+    let best_friend_ref = interner.resolve(best_friend).unwrap();
+
+    let mut set = BTreeSet::new();
+    set.insert(lonely);
+    set.insert(best_friend);
+    set.insert(threes_a_crowd);
+    set.insert(rando);
+    set.insert(best_friend_2);
+    assert_eq!(set.len(), 4);
+    assert_eq!(best_friend, best_friend_2);
+    assert_eq!(best_friend_2, best_friend_3);
+    assert_eq!(best_friend_ref, "best friend");
+}