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fixes #577 
1 parent 02d98f6 commit 8113b81

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3 files changed

+210
-1
lines changed

3 files changed

+210
-1
lines changed

‎fastcore/_modidx.py‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -639,11 +639,14 @@
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'fastcore.xtras.loads': ('xtras.html#loads', 'fastcore/xtras.py'),
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'fastcore.xtras.loads_multi': ('xtras.html#loads_multi', 'fastcore/xtras.py'),
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'fastcore.xtras.local2utc': ('xtras.html#local2utc', 'fastcore/xtras.py'),
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'fastcore.xtras.make_nullable': ('xtras.html#make_nullable', 'fastcore/xtras.py'),
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'fastcore.xtras.mapped': ('xtras.html#mapped', 'fastcore/xtras.py'),
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'fastcore.xtras.maybe_open': ('xtras.html#maybe_open', 'fastcore/xtras.py'),
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'fastcore.xtras.mk_dataclass': ('xtras.html#mk_dataclass', 'fastcore/xtras.py'),
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'fastcore.xtras.mkdir': ('xtras.html#mkdir', 'fastcore/xtras.py'),
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'fastcore.xtras.modified_env': ('xtras.html#modified_env', 'fastcore/xtras.py'),
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'fastcore.xtras.modify_exception': ('xtras.html#modify_exception', 'fastcore/xtras.py'),
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'fastcore.xtras.nullable_dc': ('xtras.html#nullable_dc', 'fastcore/xtras.py'),
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'fastcore.xtras.obj2dict': ('xtras.html#obj2dict', 'fastcore/xtras.py'),
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'fastcore.xtras.open_file': ('xtras.html#open_file', 'fastcore/xtras.py'),
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'fastcore.xtras.parse_env': ('xtras.html#parse_env', 'fastcore/xtras.py'),

‎fastcore/xtras.py‎

Lines changed: 39 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
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'ReindexCollection', 'get_source_link', 'truncstr', 'sparkline', 'modify_exception', 'round_multiple',
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'set_num_threads', 'join_path_file', 'autostart', 'EventTimer', 'stringfmt_names', 'PartialFormatter',
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'partial_format', 'utc2local', 'local2utc', 'trace', 'modified_env', 'ContextManagers', 'shufflish',
13-
'console_help', 'hl_md', 'type2str', 'dataclass_src']
13+
'console_help', 'hl_md', 'type2str', 'dataclass_src', 'nullable_dc', 'make_nullable', 'mk_dataclass']
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# %% ../nbs/03_xtras.ipynb 2
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from .imports import *
@@ -642,3 +642,41 @@ def dataclass_src(cls):
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d = "" if f.default is dataclasses.MISSING else f" = {f.default!r}"
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src += f" {f.name}: {type2str(f.type)}{d}\n"
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return src
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# %% ../nbs/03_xtras.ipynb 171
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def nullable_dc(cls):
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"Like `dataclass`, but default of `None` added to fields without defaults"
649+
from dataclasses import dataclass, field
650+
from inspect import get_annotations
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for k,v in get_annotations(cls).items():
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if not hasattr(cls,k): setattr(cls, k, field(default=None))
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return dataclass(cls)
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# %% ../nbs/03_xtras.ipynb 173
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def make_nullable(cls):
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from dataclasses import dataclass, fields, MISSING
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if hasattr(cls, '_nullable'): return
659+
cls._nullable = True
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@patch
662+
def __init__(self:cls, *args, **kwargs):
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flds = fields(cls)
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dargs = {k.name:v for k,v in zip(flds, args)}
665+
for f in flds:
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nm = f.name
667+
if nm not in dargs and nm not in kwargs and f.default is None and f.default_factory is MISSING:
668+
kwargs[nm] = None
669+
self._orig___init__(*args, **kwargs)
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for f in fields(cls):
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if f.default is MISSING and f.default_factory is MISSING: f.default = None
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# %% ../nbs/03_xtras.ipynb 177
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def mk_dataclass(cls):
676+
from dataclasses import dataclass, field, is_dataclass, MISSING
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from inspect import get_annotations
678+
if is_dataclass(cls): return make_nullable(cls)
679+
for k,v in get_annotations(cls).items():
680+
if not hasattr(cls,k) or getattr(cls,k) is MISSING:
681+
setattr(cls, k, field(default=None))
682+
dataclass(cls, init=True, repr=True, eq=True, order=False, unsafe_hash=False, frozen=False)

‎nbs/03_xtras.ipynb‎

Lines changed: 168 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2598,6 +2598,174 @@
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"print(dataclass_src(DC))"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"#| export\n",
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"def nullable_dc(cls):\n",
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" \"Like `dataclass`, but default of `None` added to fields without defaults\"\n",
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" from dataclasses import dataclass, field\n",
2611+
" from inspect import get_annotations\n",
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" for k,v in get_annotations(cls).items():\n",
2613+
" if not hasattr(cls,k): setattr(cls, k, field(default=None))\n",
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" return dataclass(cls)"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"Person(name='Bob', age=None, city='Unknown')"
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]
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},
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"execution_count": null,
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"metadata": {},
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"output_type": "execute_result"
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}
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],
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"source": [
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"@nullable_dc\n",
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"class Person: name: str; age: int; city: str = \"Unknown\"\n",
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"Person(name=\"Bob\")"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
2645+
"#| export\n",
2646+
"def make_nullable(cls):\n",
2647+
" from dataclasses import dataclass, fields, MISSING\n",
2648+
" if hasattr(cls, '_nullable'): return\n",
2649+
" cls._nullable = True\n",
2650+
"\n",
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" @patch\n",
2652+
" def __init__(self:cls, *args, **kwargs):\n",
2653+
" flds = fields(cls)\n",
2654+
" dargs = {k.name:v for k,v in zip(flds, args)}\n",
2655+
" for f in flds:\n",
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" nm = f.name\n",
2657+
" if nm not in dargs and nm not in kwargs and f.default is None and f.default_factory is MISSING:\n",
2658+
" kwargs[nm] = None\n",
2659+
" self._orig___init__(*args, **kwargs)\n",
2660+
" \n",
2661+
" for f in fields(cls):\n",
2662+
" if f.default is MISSING and f.default_factory is MISSING: f.default = None"
2663+
]
2664+
},
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{
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"cell_type": "code",
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"execution_count": null,
2668+
"metadata": {},
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"outputs": [
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{
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"data": {
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"text/plain": [
2673+
"Person(name='Bob', age=None, city='NY')"
2674+
]
2675+
},
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"execution_count": null,
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"metadata": {},
2678+
"output_type": "execute_result"
2679+
}
2680+
],
2681+
"source": [
2682+
"@dataclass\n",
2683+
"class Person: name: str; age: int; city: str = \"Unknown\"\n",
2684+
"\n",
2685+
"make_nullable(Person)\n",
2686+
"Person(\"Bob\", city='NY')"
2687+
]
2688+
},
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{
2690+
"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [
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{
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"data": {
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"text/plain": [
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"Person(name='Bob', age=None, city='Unknown')"
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]
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},
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"execution_count": null,
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"metadata": {},
2702+
"output_type": "execute_result"
2703+
}
2704+
],
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"source": [
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"Person(name=\"Bob\")"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
2712+
"metadata": {},
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"outputs": [
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{
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"data": {
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"text/plain": [
2717+
"Person(name='Bob', age=34, city='Unknown')"
2718+
]
2719+
},
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"execution_count": null,
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"metadata": {},
2722+
"output_type": "execute_result"
2723+
}
2724+
],
2725+
"source": [
2726+
"Person(\"Bob\", 34)"
2727+
]
2728+
},
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{
2730+
"cell_type": "code",
2731+
"execution_count": null,
2732+
"metadata": {},
2733+
"outputs": [],
2734+
"source": [
2735+
"#| export\n",
2736+
"def mk_dataclass(cls):\n",
2737+
" from dataclasses import dataclass, field, is_dataclass, MISSING\n",
2738+
" from inspect import get_annotations\n",
2739+
" if is_dataclass(cls): return make_nullable(cls)\n",
2740+
" for k,v in get_annotations(cls).items():\n",
2741+
" if not hasattr(cls,k) or getattr(cls,k) is MISSING:\n",
2742+
" setattr(cls, k, field(default=None))\n",
2743+
" dataclass(cls, init=True, repr=True, eq=True, order=False, unsafe_hash=False, frozen=False)"
2744+
]
2745+
},
2746+
{
2747+
"cell_type": "code",
2748+
"execution_count": null,
2749+
"metadata": {},
2750+
"outputs": [
2751+
{
2752+
"data": {
2753+
"text/plain": [
2754+
"Person(name='Bob', age=None, city='Unknown')"
2755+
]
2756+
},
2757+
"execution_count": null,
2758+
"metadata": {},
2759+
"output_type": "execute_result"
2760+
}
2761+
],
2762+
"source": [
2763+
"class Person: name: str; age: int; city: str = \"Unknown\"\n",
2764+
"\n",
2765+
"mk_dataclass(Person)\n",
2766+
"Person(name=\"Bob\")"
2767+
]
2768+
},
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{
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"cell_type": "markdown",
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"metadata": {},

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