Add support for hashing to Range type

Author: Enrico Granata

lib/aria/range/range.aria

@@ -89,6 +89,20 @@ struct RangeImpl {
     func prettyprint() {
         return "Range from={0} to={1}".format(this.from, this.to);
     }
+
+    func hash() {
+        val h = this.from ^ (this.to + 0xe3779b97f4a7c15);
+        h = h ^ (h >> 30);
+        h = h * 0xf58476d1ce4e5b9;
+        h = h ^ (h >> 27);
+        h = h * 0x4d049bb133111eb;
+        h = h ^ (h >> 31);
+        return h;
+    }
+
+    operator == (other: RangeImpl) {
+        return this.from == other.from && this.to == other.to;
+    }
 }
 
 struct RangeFrom {

tests/range_hash.aria

@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: Apache-2.0
+import Range from aria.range.range;
+
+func main() {
+    val r1 = Range.from(5).to(10);
+    val r2 = Range.from(6).to(10);
+    val r3 = Range.from(5).to(11);
+
+    assert r1.hash() != r2.hash();
+    assert r1.hash() != r3.hash();
+    assert r2.hash() != r3.hash();
+
+    assert r1.hash() == r1.hash();
+    assert r2.hash() == r2.hash();
+    assert r3.hash() == r3.hash();
+
+    val r4 = Range.from(6).to(10);
+
+    assert r4.hash() == r2.hash();
+    assert r2 == r4;
+}