Merge pull request RustPython#1544 from xarus01/master

Implemented range.__reduce__

Author: windelbouwman

tests/snippets/builtin_range.py

@@ -108,6 +108,12 @@
 assert list(reversed(range(5, 0, -1))) == [1, 2, 3, 4, 5]
 assert list(reversed(range(1,10,5))) == [6, 1]
 
+# __reduce__
+assert range(10).__reduce__()[0] == range
+assert range(10).__reduce__()[1] == (0, 10, 1)
+assert range(10, 1, -2).__reduce__()[0] == range
+assert range(10, 1, -2).__reduce__()[1] == (10, 1, -2)
+
 # range retains the original int refs
 i = 2**64
 assert range(i).stop is i

vm/src/obj/objrange.rs

@@ -7,7 +7,9 @@ use num_traits::{One, Signed, Zero};
 use super::objint::{PyInt, PyIntRef};
 use super::objiter;
 use super::objslice::{PySlice, PySliceRef};
+use super::objtuple::PyTuple;
 use super::objtype::PyClassRef;
+
 use crate::function::{OptionalArg, PyFuncArgs};
 use crate::pyhash;
 use crate::pyobject::{
@@ -298,6 +300,16 @@ impl PyRange {
         vm.ctx.not_implemented()
     }
 
+    #[pymethod(name = "__reduce__")]
+    fn reduce(&self, vm: &VirtualMachine) -> (PyClassRef, PyTuple) {
+        let range_paramters: Vec<PyObjectRef> = vec![&self.start, &self.stop, &self.step]
+            .iter()
+            .map(|x| x.as_object().clone())
+            .collect();
+        let range_paramters_tuple = PyTuple::from(range_paramters);
+        (vm.ctx.range_type(), range_paramters_tuple)
+    }
+
     #[pymethod(name = "index")]
     fn index(&self, needle: PyObjectRef, vm: &VirtualMachine) -> PyResult<BigInt> {
         if let Ok(int) = needle.downcast::<PyInt>() {