From cc26a2e20ea2609c5521f1336d31480b17dd013f Mon Sep 17 00:00:00 2001
From: Matt Craighead <mjcraighead@gmail.com>
Date: Sun, 30 Oct 2011 18:32:28 -0700
Subject: [PATCH] zip now returns an iterator

---
 backend.cpp | 51 +++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/backend.cpp b/backend.cpp
index 68053a9..d46925f 100644
--- a/backend.cpp
+++ b/backend.cpp
@@ -1425,26 +1425,49 @@ public:
 };
 
 class zip_class_def_singleton: public builtin_class_def_singleton {
-public:
-    zip_class_def_singleton(): builtin_class_def_singleton("zip") {}
+private:
+    class zip_obj: public node {
+    private:
+        node *iter1;
+        node *iter2;
 
-    virtual node *__call__(context *globals, context *ctx, tuple *args, dict *kwargs) {
-        NO_KWARGS_N_ARGS("zip", 2);
-        node *list1 = args->__getitem__(0);
-        node *list2 = args->__getitem__(1);
+    public:
+        zip_obj(node *iter1, node *iter2) {
+            this->iter1 = iter1;
+            this->iter2 = iter2;
+        }
+        const char *node_type() { return "zip_obj"; }
 
-        if (!list1->is_list() || !list2->is_list() || list1->len() != list2->len())
-            error("bad arguments to zip()");
+        virtual void mark_live() {
+            if (!allocator->mark_live(this, sizeof(*this))) {
+                this->iter1->mark_live();
+                this->iter2->mark_live();
+            }
+        }
 
-        list *plist = new(allocator) list();
-        for (int_t i = 0; i < list1->len(); i++) {
+        virtual node *__iter__() { return this; }
+        virtual node *next() {
+            node *item1 = this->iter1->next();
+            node *item2 = this->iter2->next();
+            if (!item1 || !item2)
+                return NULL;
             node *pair[2];
-            pair[0] = list1->__getitem__(i);
-            pair[1] = list2->__getitem__(i);
-            plist->append(new(allocator) tuple(2, pair));
+            pair[0] = item1;
+            pair[1] = item2;
+            return new(allocator) tuple(2, pair);
         }
 
-        return plist;
+        virtual std::string repr() { return "<zip object>"; }
+    };
+
+public:
+    zip_class_def_singleton(): builtin_class_def_singleton("zip") {}
+
+    virtual node *__call__(context *globals, context *ctx, tuple *args, dict *kwargs) {
+        NO_KWARGS_N_ARGS("zip", 2);
+        node *iter1 = args->__getitem__(0)->__iter__();
+        node *iter2 = args->__getitem__(1)->__iter__();
+        return new(allocator) zip_obj(iter1, iter2);
     }
 };
 
-- 
2.11.4.GIT