132 lines
3.8 KiB
Python
132 lines
3.8 KiB
Python
# cybertools.meta.element
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""" Building flexible hierarchical object structures with XML-like
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elements.
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"""
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from io import StringIO
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from cybertools.util.jeep import Jeep
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_not_found = object()
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class Element(dict):
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typeName = 'Element'
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posArgs = ('__name__',)
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realAttributes = ('namespace', '__name__', 'factory', 'parent', 'children')
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def __init__(self, namespace, name, factory=None, parent=None):
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self.namespace = namespace
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self.__name__ = name
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self.parent = parent
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self.factory = factory
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self.children = Jeep()
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def __call__(self, *args, **kw):
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for idx, v in enumerate(args):
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if isinstance(v, Element):
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self[v.__name__] = v
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elif idx < len(self.posArgs):
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self[self.posArgs[idx]] = v
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for k, v in kw.items():
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self[k] = v
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return self
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def __getitem__(self, key):
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if isinstance(key, (list, tuple)):
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return tuple(self[k] for k in key)
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elif isinstance(key, Element):
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self.children.append(key)
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return key
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elif isinstance(key, (int, str)):
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return self.children[key]
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else:
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raise KeyError(key)
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def __getattr__(self, key):
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result = self.get(key, _not_found)
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if result is _not_found:
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result = self.children.get(key, _not_found)
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if result is _not_found:
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raise AttributeError(key)
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return result
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def __setattr__(self, key, value):
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if key in self.realAttributes or key.startswith('_'):
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super(Element, self).__setattr__(key, value)
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else:
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self[key] = value
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#def __iter__(self):
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# return iter(self.children)
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def __str__(self):
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return self.__name__
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def __repr__(self):
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return "<%s '%s'>" % (self.typeName, self.__name__)
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class ElementFactory(object):
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elementClass = Element
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def __init__(self, namespace, name):
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self.namespace = namespace
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self.__name__ = name
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self.instances = []
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def __call__(self, *args, **kw):
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elem = self.elementClass(self.namespace, '', factory=self)
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for idx, v in enumerate(args):
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if idx < len(elem.posArgs):
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elem[elem.posArgs[idx]] = v
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for k, v in kw.items():
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elem[k] = v
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elem.__name__ = elem.get('__name__')
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if not elem.__name__:
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elem.__name__ = self.__name__
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self.instances.append(elem)
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return elem
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class AutoElement(Element):
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typeName = 'AutoElement'
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def __getattr__(self, key):
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if key.startswith('_'): # no auto-creation for special attributes
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raise AttributeError(key)
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result = self.get(key, _not_found)
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if result is _not_found:
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result = self.children.get(key, _not_found)
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if result is _not_found:
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result = self.__class__(self.namespace, key, parent=self)
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self.children[key] = result
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return result
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def __getitem__(self, key):
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try:
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return super(AutoElement, self).__getitem__(key)
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except KeyError:
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if isinstance(key, basestring):
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result = self.__class__(self.namespace, key, parent=self)
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self.children[key] = result
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return result
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else:
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raise KeyError(key)
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def __str__(self):
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out = StringIO()
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for v in self.children:
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out.write('%s.%s\n' % (self.__name__, v))
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if self or not self.children:
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out.write(self.__name__)
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if self:
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out.write('(')
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out.write(', '.join('%s=%r' % (k, v) for k, v in self.items()))
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out.write(')')
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return out.getvalue()
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