Fix generator for unions

packages/schema/generate-spec.py

@@ -5,8 +5,22 @@
 import json
 from operator import itemgetter
 
-from traitlets import (CaselessStrEnum, Unicode, Tuple, List, Bool, CFloat,
- Float, CInt, Int, Instance, Dict, Bytes, Any)
+from traitlets import (
+ CaselessStrEnum,
+ Unicode,
+ Tuple,
+ List,
+ Bool,
+ CFloat,
+ Float,
+ CInt,
+ Int,
+ Instance,
+ Dict,
+ Bytes,
+ Any,
+ Union,
+)
 
 import ipywidgets as widgets
 from ipywidgets import Color
@@ -62,7 +76,16 @@ def trait_type(trait, widget_list):
  w_type = 'color'
  elif isinstance(trait, Dict):
  w_type = 'object'
- elif isinstance(trait, Bytes) or isinstance(trait, ByteMemoryView):
+ elif isinstance(trait, Union):
+ union_attributes = []
+ union_types = []
+ for ut in trait.trait_types:
+ ua = trait_type(ut, widget_list)
+ union_attributes.append(ua)
+ union_types.append(ua['type'])
+ w_type = union_types
+ attributes['union_attributes'] = union_attributes
+ elif isinstance(trait, (Bytes, ByteMemoryView)):
  w_type = 'bytes'
  elif isinstance(trait, Instance) and issubclass(trait.klass,
  widgets.Widget):
@@ -89,6 +112,8 @@ def jsdefault(trait):
  default = trait.make_dynamic_default()
  if issubclass(trait.klass, widgets.Widget):
  return 'reference to new instance'
+ elif isinstance(trait, Union):
+ default = trait.make_dynamic_default()
  else:
  default = trait.default_value
  if isinstance(default, bytes) or isinstance(default, memoryview):
@@ -112,6 +137,10 @@ def mddefault(attribute):
 
 def mdtype(attribute):
  md_type = attribute['type']
+ if 'union_attributes' in attribute and isinstance(md_type, (list, tuple)):
+ md_type = ' or '.join(
+ mdtype(ua) for ua in attribute['union_attributes']
+ )
  if md_type in NUMBER_MAP:
  md_type = NUMBER_MAP[md_type]
  if attribute.get('allow_none'):