Implement tuple hashing

src/runtime/tuple.cpp

@@ -19,6 +19,8 @@
 #include "core/stats.h"
 #include "core/types.h"
 
+#include "codegen/compvars.h"
+
 #include "runtime/gc_runtime.h"
 #include "runtime/objmodel.h"
 #include "runtime/types.h"
@@ -174,6 +176,19 @@ Box* tupleContains(BoxedTuple* self, Box* elt) {
     return False;
 }
 
+Box* tupleHash(BoxedTuple* self) {
+    assert(self->cls == tuple_cls);
+
+    int64_t rtn = 3527539;
+    for (Box* e : self->elts) {
+        BoxedInt* h = hash(e);
+        assert(h->cls == int_cls);
+        rtn ^= h->n + 0x9e3779b9 + (rtn << 6) + (rtn >> 2);
+    }
+
+    return boxInt(rtn);
+}
+
 void setupTuple() {
     tuple_cls->giveAttr("__name__", boxStrConstant("tuple"));
 
@@ -187,6 +202,7 @@ void setupTuple() {
     tuple_cls->giveAttr("__eq__", new BoxedFunction(boxRTFunction((void*)tupleEq, NULL, 2, false)));
     tuple_cls->giveAttr("__ne__", new BoxedFunction(boxRTFunction((void*)tupleNe, NULL, 2, false)));
 
+    tuple_cls->giveAttr("__hash__", new BoxedFunction(boxRTFunction((void*)tupleHash, BOXED_INT, 1, false)));
     tuple_cls->giveAttr("__len__", new BoxedFunction(boxRTFunction((void*)tupleLen, NULL, 1, false)));
     tuple_cls->giveAttr("__repr__", new BoxedFunction(boxRTFunction((void*)tupleRepr, NULL, 1, false)));
     tuple_cls->setattr("__str__", tuple_cls->peekattr("__repr__"), NULL, NULL);

test/tests/tuples.py

@@ -47,6 +47,9 @@ class T(object):
         print "eq", self.n, rhs.n
         return self.n == rhs.n
 
+    def __hash__(self):
+        return hash(self.n)
+
     def __repr__(self):
         return "<T>"
 
@@ -57,6 +60,7 @@ def t(l, r):
     print l >= r
     print l == r
     print l != r
+    print "same hash: " , hash(l) == hash(r)
 
 t(T(1), T(2))
 t(T(1), T(1))