fixes #803

Author: jph00

fastcore/_modidx.py

@@ -852,6 +852,7 @@
                                 'fastcore.xtras.stringfmt_names': ('xtras.html#stringfmt_names', 'fastcore/xtras.py'),
                                 'fastcore.xtras.time_policy': ('xtras.html#time_policy', 'fastcore/xtras.py'),
                                 'fastcore.xtras.timed_cache': ('xtras.html#timed_cache', 'fastcore/xtras.py'),
+                                'fastcore.xtras.to_aiter': ('xtras.html#to_aiter', 'fastcore/xtras.py'),
                                 'fastcore.xtras.trace': ('xtras.html#trace', 'fastcore/xtras.py'),
                                 'fastcore.xtras.trim_wraps': ('xtras.html#trim_wraps', 'fastcore/xtras.py'),
                                 'fastcore.xtras.truncstr': ('xtras.html#truncstr', 'fastcore/xtras.py'),

fastcore/xtras.py

@@ -13,8 +13,8 @@
            'stringfmt_names', 'PartialFormatter', 'partial_format', 'truncstr', 'utc2local', 'local2utc', 'trace',
            'modified_env', 'ContextManagers', 'shufflish', 'console_help', 'hl_md', 'type2str', 'dataclass_src',
            'Unset', 'nullable_dc', 'make_nullable', 'flexiclass', 'asdict', 'vars_pub', 'is_typeddict', 'is_namedtuple',
-           'CachedIter', 'CachedAwaitable', 'reawaitable', 'is_async_callable', 'maybe_await', 'maybe_aiter', 'mapa',
-           'noopa', 'flexicache', 'time_policy', 'mtime_policy', 'timed_cache']
+           'CachedIter', 'CachedAwaitable', 'reawaitable', 'is_async_callable', 'maybe_await', 'to_aiter',
+           'maybe_aiter', 'mapa', 'noopa', 'flexicache', 'time_policy', 'mtime_policy', 'timed_cache']
 
 # %% ../nbs/03_xtras.ipynb #3401d507
 from .imports import *
@@ -1029,16 +1029,17 @@ async def maybe_await(o):
     from inspect import isawaitable
     return await o if isawaitable(o) else o
 
-# %% ../nbs/03_xtras.ipynb #985e3551
+# %% ../nbs/03_xtras.ipynb #fc70459b
+async def to_aiter(items):
+    "Async yield each item in `items` with `asyncio.sleep(0)` between"
+    for item in items:
+        await asyncio.sleep(0)
+        yield item
+
+# %% ../nbs/03_xtras.ipynb #5337427e
 def maybe_aiter(items):
-    "Convert `items` to async generator if needed, and return it"
-    if hasattr(items, '__aiter__'): return items
-    else:
-        async def f(items):
-            for item in items:
-                await asyncio.sleep(0)
-                yield item
-        return f(items)
+    "If `items` already async, return it; otherwise to_aiter"
+    return items if hasattr(items, '__aiter__') else to_aiter(items)
 
 # %% ../nbs/03_xtras.ipynb #371d5196
 async def mapa(f, items):

nbs/03_xtras.ipynb

@@ -2368,7 +2368,7 @@
     {
      "data": {
       "text/plain": [
-       "['c', 'a', 'g', 'e', 'd', 'h', 'b', 'f']"
+       "['e', 'b', 'c', 'g', 'h', 'a', 'f', 'd']"
       ]
      },
      "execution_count": null,
@@ -2855,7 +2855,7 @@
     {
      "data": {
       "text/plain": [
-       "'_oD33Ew5VRVG3N4nztl2CDg'"
+       "'_mutjsmXKSHeVjFdUFGSgNw'"
       ]
      },
      "execution_count": null,
@@ -2952,7 +2952,7 @@
     {
      "data": {
       "text/plain": [
-       "('4d760890', '8c7d7247')"
+       "('215346fd', '8c7d7247')"
       ]
      },
      "execution_count": null,
@@ -3714,8 +3714,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "Num Events: 9, Freq/sec: 353.6\n",
-      "Most recent:  ▃▂▇▁▆ 262.9 253.7 278.7 240.9 273.2\n"
+      "Num Events: 9, Freq/sec: 338.8\n",
+      "Most recent:  ▆▂▇▁▆ 280.6 255.3 284.5 238.9 279.7\n"
      ]
     }
    ],
@@ -4953,33 +4953,54 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "985e3551",
+   "id": "fc70459b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#| export\n",
+    "async def to_aiter(items):\n",
+    "    \"Async yield each item in `items` with `asyncio.sleep(0)` between\"\n",
+    "    for item in items:\n",
+    "        await asyncio.sleep(0)\n",
+    "        yield item"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "879e3a1e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "test_eq([o async for o in to_aiter([10,20,30])], [10,20,30])\n",
+    "test_eq([o async for o in to_aiter([])], [])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "5337427e",
    "metadata": {},
    "outputs": [],
    "source": [
     "#| export\n",
     "def maybe_aiter(items):\n",
-    "    \"Convert `items` to async generator if needed, and return it\"\n",
-    "    if hasattr(items, '__aiter__'): return items\n",
-    "    else:\n",
-    "        async def f(items):\n",
-    "            for item in items:\n",
-    "                await asyncio.sleep(0)\n",
-    "                yield item\n",
-    "        return f(items)"
+    "    \"If `items` already async, return it; otherwise to_aiter\"\n",
+    "    return items if hasattr(items, '__aiter__') else to_aiter(items)"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "d8c47321",
+   "id": "b4d75116",
    "metadata": {},
    "outputs": [],
    "source": [
     "async def _agen():\n",
     "    for i in [1,2,3]: yield i\n",
     "\n",
-    "test_eq(maybe_aiter(aiter_:=_agen()), aiter_)  # already async, returned as-is\n",
+    "ag = _agen()\n",
+    "test_eq([o async for o in maybe_aiter(ag)], [1,2,3])\n",
     "test_eq([o async for o in maybe_aiter([1,2,3])], [1,2,3])"
    ]
   },