fixes #618

Author: jph00

fastcore/_modidx.py

@@ -94,6 +94,7 @@
                                  'fastcore.basics._mk_op': ('basics.html#_mk_op', 'fastcore/basics.py'),
                                  'fastcore.basics._nested_idx': ('basics.html#_nested_idx', 'fastcore/basics.py'),
                                  'fastcore.basics._oper': ('basics.html#_oper', 'fastcore/basics.py'),
+                                 'fastcore.basics._risinstance': ('basics.html#_risinstance', 'fastcore/basics.py'),
                                  'fastcore.basics._store_attr': ('basics.html#_store_attr', 'fastcore/basics.py'),
                                  'fastcore.basics._typeerr': ('basics.html#_typeerr', 'fastcore/basics.py'),
                                  'fastcore.basics._using_attr': ('basics.html#_using_attr', 'fastcore/basics.py'),

fastcore/basics.py

@@ -159,14 +159,17 @@ def exec_local(code, var_name):
     return loc[var_name]
 
 # %% ../nbs/01_basics.ipynb
-def risinstance(types, obj=None):
-    "Curried `isinstance` but with args reversed"
-    types = tuplify(types)
-    if obj is None: return partial(risinstance,types)
+def _risinstance(types, obj):
     if any(isinstance(t,str) for t in types):
         return any(t.__name__ in types for t in type(obj).__mro__)
     return isinstance(obj, types)
 
+def risinstance(types, obj=None):
+    "Curried `isinstance` but with args reversed"
+    types = tuplify(types)
+    if obj is None: return partial(_risinstance,types)
+    return _risinstance(types, obj)
+
 # %% ../nbs/01_basics.ipynb
 def ver2tuple(v:str)->tuple:
     return tuple(int(o or 0) for o in re.search(r'(\d+)(?:\.(\d+))?(?:\.(\d+))?', v).groups())

nbs/01_basics.ipynb

@@ -594,7 +594,7 @@
       "text/markdown": [
        "---\n",
        "\n",
-       "[source](https://github.com/fastai/fastcore/blob/master/fastcore/basics.py#L104){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/fastai/fastcore/blob/master/fastcore/basics.py#L105){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "### get_class\n",
        "\n",
@@ -606,7 +606,7 @@
       "text/plain": [
        "---\n",
        "\n",
-       "[source](https://github.com/fastai/fastcore/blob/master/fastcore/basics.py#L104){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/fastai/fastcore/blob/master/fastcore/basics.py#L105){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "### get_class\n",
        "\n",
@@ -784,7 +784,7 @@
       "text/markdown": [
        "---\n",
        "\n",
-       "[source](https://github.com/fastai/fastcore/blob/master/fastcore/basics.py#L148){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/fastai/fastcore/blob/master/fastcore/basics.py#L149){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "#### ignore_exceptions\n",
        "\n",
@@ -795,7 +795,7 @@
       "text/plain": [
        "---\n",
        "\n",
-       "[source](https://github.com/fastai/fastcore/blob/master/fastcore/basics.py#L148){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
+       "[source](https://github.com/fastai/fastcore/blob/master/fastcore/basics.py#L149){target=\"_blank\" style=\"float:right; font-size:smaller\"}\n",
        "\n",
        "#### ignore_exceptions\n",
        "\n",
@@ -854,13 +854,16 @@
    "outputs": [],
    "source": [
     "#|export\n",
+    "def _risinstance(types, obj):\n",
+    "    if any(isinstance(t,str) for t in types):\n",
+    "        return any(t.__name__ in types for t in type(obj).__mro__)\n",
+    "    return isinstance(obj, types)\n",
+    "\n",
     "def risinstance(types, obj=None):\n",
     "    \"Curried `isinstance` but with args reversed\"\n",
     "    types = tuplify(types)\n",
-    "    if obj is None: return partial(risinstance,types)\n",
-    "    if any(isinstance(t,str) for t in types):\n",
-    "        return any(t.__name__ in types for t in type(obj).__mro__)\n",
-    "    return isinstance(obj, types)"
+    "    if obj is None: return partial(_risinstance,types)\n",
+    "    return _risinstance(types, obj)"
    ]
   },
   {
@@ -871,7 +874,8 @@
    "source": [
     "assert risinstance(int, 1)\n",
     "assert not risinstance(str, 0)\n",
-    "assert risinstance(int)(1)"
+    "assert risinstance(int)(1)\n",
+    "assert not risinstance(int)(None)"
    ]
   },
   {