fixes #145

Author: jph00

fastcore/_nbdev.py

@@ -179,6 +179,8 @@
          "PrePostInitMeta": "06_meta.ipynb",
          "NewChkMeta": "06_meta.ipynb",
          "BypassNewMeta": "06_meta.ipynb",
+         "empty2none": "06_meta.ipynb",
+         "anno_dict": "06_meta.ipynb",
          "use_kwargs_dict": "06_meta.ipynb",
          "use_kwargs": "06_meta.ipynb",
          "delegates": "06_meta.ipynb",

fastcore/meta.py

@@ -1,7 +1,7 @@
 # AUTOGENERATED! DO NOT EDIT! File to edit: nbs/06_meta.ipynb (unless otherwise specified).
 
-__all__ = ['test_sig', 'FixSigMeta', 'PrePostInitMeta', 'NewChkMeta', 'BypassNewMeta', 'use_kwargs_dict', 'use_kwargs',
-           'delegates', 'method', 'funcs_kwargs']
+__all__ = ['test_sig', 'FixSigMeta', 'PrePostInitMeta', 'NewChkMeta', 'BypassNewMeta', 'empty2none', 'anno_dict',
+           'use_kwargs_dict', 'use_kwargs', 'delegates', 'method', 'funcs_kwargs']
 
 # Cell
 from .imports import *
@@ -57,6 +57,16 @@ def __call__(cls, x=None, *args, **kwargs):
         if cls!=x.__class__: x.__class__ = cls
         return x
 
+# Cell
+def empty2none(p):
+    "Replace `Parameter.empty` with `None`"
+    return None if p==inspect.Parameter.empty else p
+
+# Cell
+def anno_dict(f):
+    "`__annotation__ dictionary with `empty` cast to `None`, returning empty if doesn't exist"
+    return {k:empty2none(v) for k,v in getattr(f, '__annotations__', {}).items()}
+
 # Cell
 def _mk_param(n,d=None): return inspect.Parameter(n, inspect.Parameter.KEYWORD_ONLY, default=d)
 

nbs/02_utils.ipynb

@@ -296,7 +296,7 @@
     {
      "data": {
       "text/plain": [
-       "<__main__._t at 0x7fd8de963850>"
+       "<__main__._t at 0x7f2feeb9ec10>"
       ]
      },
      "execution_count": null,
@@ -1977,7 +1977,7 @@
     {
      "data": {
       "text/plain": [
-       "{0: 'A', 1: 'B', 2: 'C', 5: 'F', 6: 'G'}"
+       "{70: 'F', 71: 'G'}"
       ]
      },
      "execution_count": null,
@@ -2009,7 +2009,7 @@
     {
      "data": {
       "text/plain": [
-       "{0: 'A', 1: 'B', 2: 'C'}"
+       "{}"
       ]
      },
      "execution_count": null,
@@ -2041,7 +2041,7 @@
     {
      "data": {
       "text/plain": [
-       "{5: 'F', 6: 'G'}"
+       "{70: 'F', 71: 'G'}"
       ]
      },
      "execution_count": null,
@@ -2362,7 +2362,7 @@
     {
      "data": {
       "text/plain": [
-       "['c', 'a', 'f', 'g', 'h', 'd', 'e', 'b']"
+       "['e', 'd', 'h', 'f', 'c', 'b', 'g', 'a']"
       ]
      },
      "execution_count": null,
@@ -3121,7 +3121,7 @@
     {
      "data": {
       "text/plain": [
-       "Path('.gitattributes')"
+       "Path('.ipynb_checkpoints')"
       ]
      },
      "execution_count": null,
@@ -3155,7 +3155,7 @@
     {
      "data": {
       "text/plain": [
-       "(Path('../fastcore/all.py'), Path('00_test.ipynb'))"
+       "(Path('../fastcore/logargs.py'), Path('04_transform.ipynb'))"
       ]
      },
      "execution_count": null,
@@ -3719,7 +3719,7 @@
     {
      "data": {
       "text/plain": [
-       "8"
+       "64"
       ]
      },
      "execution_count": null,

nbs/06_meta.ipynb

@@ -690,6 +690,40 @@
     "## Metaprogramming"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#export\n",
+    "def empty2none(p):\n",
+    "    \"Replace `Parameter.empty` with `None`\"\n",
+    "    return None if p==inspect.Parameter.empty else p"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#export\n",
+    "def anno_dict(f):\n",
+    "    \"`__annotation__ dictionary with `empty` cast to `None`, returning empty if doesn't exist\"\n",
+    "    return {k:empty2none(v) for k,v in getattr(f, '__annotations__', {}).items()}"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def _f(a:int, b:L)->str: ...\n",
+    "test_eq(anno_dict(_f), {'a': int, 'b': L, 'return': str})"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,