Merge pull request RustPython#273 from skinny121/tuple_add

Add tuple.__add__

Author: windelbouwman

parser/src/lib.rs

@@ -7,6 +7,7 @@ extern crate num_traits;
 pub mod ast;
 pub mod lexer;
 pub mod parser;
+#[cfg_attr(rustfmt, rustfmt_skip)]
 mod python;
 pub mod token;
 

tests/snippets/tuple.py

@@ -6,6 +6,8 @@
 y = (1,)
 assert y[0] == 1
 
+assert x + y == (1, 2, 1)
+
 assert x * 3 == (1, 2, 1, 2, 1, 2)
 # assert 3 * x == (1, 2, 1, 2, 1, 2)
 assert x * 0 == ()

vm/src/obj/objtuple.rs

@@ -10,6 +10,27 @@ use super::objtype;
 use num_bigint::ToBigInt;
 use std::hash::{Hash, Hasher};
 
+fn tuple_add(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
+    arg_check!(
+        vm,
+        args,
+        required = [(zelf, Some(vm.ctx.tuple_type())), (other, None)]
+    );
+
+    if objtype::isinstance(other, &vm.ctx.tuple_type()) {
+        let e1 = get_elements(zelf);
+        let e2 = get_elements(other);
+        let elements = e1.iter().chain(e2.iter()).map(|e| e.clone()).collect();
+        Ok(vm.ctx.new_tuple(elements))
+    } else {
+        Err(vm.new_type_error(format!(
+            "Cannot add {} and {}",
+            zelf.borrow(),
+            other.borrow()
+        )))
+    }
+}
+
 fn tuple_count(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
     arg_check!(
         vm,
@@ -165,6 +186,7 @@ pub fn tuple_contains(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
 
 pub fn init(context: &PyContext) {
     let ref tuple_type = context.tuple_type;
+    context.set_attr(&tuple_type, "__add__", context.new_rustfunc(tuple_add));
     context.set_attr(&tuple_type, "__eq__", context.new_rustfunc(tuple_eq));
     context.set_attr(
         &tuple_type,