Allow setting attributes to None as a noop, for convenience.
[wrw.git] / wrw / sp / cons.py
... / ...
CommitLineData
1import xml.dom.minidom
2
3class node(object):
4 pass
5
6class text(node, unicode):
7 def __todom__(self, doc):
8 return doc.createTextNode(self)
9
10class raw(node, unicode):
11 def __todom__(self, doc):
12 raise Exception("Cannot convert raw code to DOM objects")
13
14class element(node):
15 def __init__(self, ns, name, ctx):
16 self.ns = ns
17 self.name = unicode(name)
18 self.ctx = ctx
19 self.attrs = {}
20 self.children = []
21
22 def __call__(self, *children, **attrs):
23 for child in children:
24 self.ctx.addchild(self, child)
25 for k, v in attrs.iteritems():
26 self.ctx.addattr(self, k, v)
27 return self
28
29 def __todom__(self, doc):
30 el = doc.createElementNS(self.ns, self.name)
31 for k, v in self.attrs.iteritems():
32 el.setAttribute(k, v)
33 for child in self.children:
34 el.appendChild(child.__todom__(doc))
35 return el
36
37 def __str__(self):
38 doc = xml.dom.minidom.Document()
39 return self.__todom__(doc).toxml()
40
41class context(object):
42 def __init__(self):
43 self.nodeconv = {}
44 self.nodeconv[str] = lambda ob: text(ob, "utf-8")
45 self.nodeconv[unicode] = text
46 self.nodeconv[int] = text
47 self.nodeconv[long] = text
48 self.nodeconv[float] = text
49
50 def nodefrom(self, ob):
51 if isinstance(ob, node):
52 return ob
53 if hasattr(ob, "__tonode__"):
54 return ob.__tonode__()
55 if type(ob) in self.nodeconv:
56 return self.nodeconv[type(ob)](ob)
57 raise Exception("No node conversion known for %s objects" % str(type(ob)))
58
59 def addchild(self, node, child):
60 node.children.append(self.nodefrom(child))
61
62 def addattr(self, node, k, v):
63 if v is not None:
64 node.attrs[unicode(k)] = unicode(v)
65
66class constructor(object):
67 def __init__(self, ns, elcls=element, ctx=None):
68 self._ns = ns
69 self._elcls = elcls
70 if ctx is None: ctx = context()
71 self._ctx = ctx
72
73 def __getattr__(self, name):
74 return self._elcls(self._ns, name, self._ctx)