def __new__(metacls, clsname, bases, clsdict, **kwargs):
if hasattr(clsdict, 'tags'):
# ▼ Collect all base class tag dicts + current class tag dict
tagDicts = filter(None, (parent.__dict__.get('__tags__')
for parent in bases))
tagsItems = (item
for tagsDict in attachItem(tagDicts, clsdict.tags)
for item in tagsDict.items())
# ▼ Merge all tags by tag name
newTags = {}
getIndex = itemgetter(0)
for k, g in groupby(sorted(tagsItems, key=getIndex), getIndex):
newTags[k] = tuple(chain.from_iterable((i[1] for i in g)))
# ▼ Check for name collisions
for tagname, tags in newTags.items():
if len(set(tags)) < len(tags):
raise AttributeError(
f"Class {clsname} has attr name conflict with base class in category {tagname}"
f" (test. name is: {(tag for tag in tags if tag not in set(tags)).__next__()}"
)
clsdict['__tags__'] = newTags
return super().__new__(metacls, clsname, bases, dict(clsdict),
**kwargs)
def collectDefaults(bases, currentDefaults):
dicts = attachItem(iterable=filter(None,
(parent.__dict__.get('_defaults_')
for parent in reversed(bases))),
append=currentDefaults)
newDefaults = dicts.__next__().copy()
for defaults in dicts:
newDefaults.update(defaults)
return newDefaults
def mergeTags(parents, currentTags):
# Collect all base class tags dicts + current class tags dict
tagsDicts = attachItem(filter(None, (parent.__dict__.get('__tags__') for parent in parents)), currentTags)
# Take main parent's tags as base tags dict
try: newTags = tagsDicts.__next__().copy()
# Use current tags if no single parent defines any
except StopIteration: return currentTags
# Merge all tags by tag name into 'newTags'
for tagsDict in tagsDicts:
reduceItems = ((tagname, newTags[tagname] | namesSet) for tagname, namesSet in tagsDict.items())
for _ in starmap(partial(setitem, newTags), reduceItems): pass
# TODO: Compare performance ▲ ▼, if negligible - replace with code below (more readable IMHO)
# for tagname, updatedNamesSet in reduceItems:
# setitem(newTags, tagname, updatedNamesSet)
return newTags
def mergeParentDicts(parents, dictName, currentDict):
dicts = attachItem(
filter(None, (parent.__dict__.get(dictName) for parent in reversed(parents))), currentDict)
newDict = dicts.__next__().copy()
for attrDict in dicts: newDict.update(attrDict)
return newDict