Mercurial > genshi > mirror
annotate markup/builder.py @ 162:456039594db9 trunk
Implement the XPath relational operators and the `round()` function.
| author | cmlenz |
|---|---|
| date | Wed, 16 Aug 2006 22:48:48 +0000 |
| parents | 79f445396cd7 |
| children | 2f30ce3fb85e |
| rev | line source |
|---|---|
| 1 | 1 # -*- coding: utf-8 -*- |
| 2 # | |
|
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3 # Copyright (C) 2006 Edgewall Software |
| 1 | 4 # All rights reserved. |
| 5 # | |
| 6 # This software is licensed as described in the file COPYING, which | |
| 7 # you should have received as part of this distribution. The terms | |
|
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8 # are also available at http://markup.edgewall.org/wiki/License. |
| 1 | 9 # |
| 10 # This software consists of voluntary contributions made by many | |
| 11 # individuals. For the exact contribution history, see the revision | |
|
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12 # history and logs, available at http://markup.edgewall.org/log/. |
| 1 | 13 |
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14 from markup.core import Attributes, Namespace, QName, Stream, START, END, TEXT |
| 1 | 15 |
| 16 __all__ = ['Fragment', 'Element', 'tag'] | |
| 17 | |
| 18 | |
| 19 class Fragment(object): | |
| 28 | 20 """Represents a markup fragment, which is basically just a list of element |
| 21 or text nodes. | |
| 22 """ | |
| 1 | 23 __slots__ = ['children'] |
| 24 | |
| 25 def __init__(self): | |
| 26 self.children = [] | |
| 27 | |
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28 def __add__(self, other): |
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29 return Fragment()(self, other) |
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30 |
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31 def __call__(self, *args): |
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32 map(self.append, args) |
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33 return self |
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34 |
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35 def __iter__(self): |
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36 return self._generate() |
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37 |
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38 def __repr__(self): |
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39 return '<%s>' % self.__class__.__name__ |
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40 |
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41 def __str__(self): |
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42 return str(self.generate()) |
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43 |
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44 def __unicode__(self): |
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45 return unicode(self.generate()) |
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46 |
| 1 | 47 def append(self, node): |
| 48 """Append an element or string as child node.""" | |
| 49 if isinstance(node, (Element, basestring, int, float, long)): | |
| 50 # For objects of a known/primitive type, we avoid the check for | |
| 51 # whether it is iterable for better performance | |
| 52 self.children.append(node) | |
| 53 elif isinstance(node, Fragment): | |
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54 self.children.extend(node.children) |
| 1 | 55 elif node is not None: |
| 56 try: | |
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57 map(self.append, iter(node)) |
| 1 | 58 except TypeError: |
| 59 self.children.append(node) | |
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60 |
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61 def _generate(self): |
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62 for child in self.children: |
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63 if isinstance(child, Fragment): |
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64 for event in child._generate(): |
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65 yield event |
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66 else: |
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67 if not isinstance(child, basestring): |
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68 child = unicode(child) |
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69 yield TEXT, child, (None, -1, -1) |
| 1 | 70 |
| 71 def generate(self): | |
| 28 | 72 """Return a markup event stream for the fragment.""" |
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73 return Stream(self._generate()) |
| 1 | 74 |
| 75 | |
| 76 class Element(Fragment): | |
| 77 """Simple XML output generator based on the builder pattern. | |
| 78 | |
| 79 Construct XML elements by passing the tag name to the constructor: | |
| 80 | |
| 81 >>> print Element('strong') | |
| 82 <strong/> | |
| 83 | |
| 84 Attributes can be specified using keyword arguments. The values of the | |
| 85 arguments will be converted to strings and any special XML characters | |
| 86 escaped: | |
| 87 | |
| 88 >>> print Element('textarea', rows=10, cols=60) | |
| 89 <textarea rows="10" cols="60"/> | |
| 90 >>> print Element('span', title='1 < 2') | |
| 91 <span title="1 < 2"/> | |
| 92 >>> print Element('span', title='"baz"') | |
| 93 <span title=""baz""/> | |
| 94 | |
| 95 The " character is escaped using a numerical entity. | |
| 96 The order in which attributes are rendered is undefined. | |
| 97 | |
| 98 If an attribute value evaluates to `None`, that attribute is not included | |
| 99 in the output: | |
| 100 | |
| 101 >>> print Element('a', name=None) | |
| 102 <a/> | |
| 103 | |
| 104 Attribute names that conflict with Python keywords can be specified by | |
| 105 appending an underscore: | |
| 106 | |
| 107 >>> print Element('div', class_='warning') | |
| 108 <div class="warning"/> | |
| 109 | |
| 110 Nested elements can be added to an element using item access notation. | |
| 111 The call notation can also be used for this and for adding attributes | |
| 112 using keyword arguments, as one would do in the constructor. | |
| 113 | |
| 114 >>> print Element('ul')(Element('li'), Element('li')) | |
| 115 <ul><li/><li/></ul> | |
| 116 >>> print Element('a')('Label') | |
| 117 <a>Label</a> | |
| 118 >>> print Element('a')('Label', href="target") | |
| 119 <a href="target">Label</a> | |
| 120 | |
| 121 Text nodes can be nested in an element by adding strings instead of | |
| 122 elements. Any special characters in the strings are escaped automatically: | |
| 123 | |
| 124 >>> print Element('em')('Hello world') | |
| 125 <em>Hello world</em> | |
| 126 >>> print Element('em')(42) | |
| 127 <em>42</em> | |
| 128 >>> print Element('em')('1 < 2') | |
| 129 <em>1 < 2</em> | |
| 130 | |
| 131 This technique also allows mixed content: | |
| 132 | |
| 133 >>> print Element('p')('Hello ', Element('b')('world')) | |
| 134 <p>Hello <b>world</b></p> | |
| 135 | |
| 34 | 136 Quotes are not escaped inside text nodes: |
| 137 >>> print Element('p')('"Hello"') | |
| 138 <p>"Hello"</p> | |
| 139 | |
| 1 | 140 Elements can also be combined with other elements or strings using the |
| 141 addition operator, which results in a `Fragment` object that contains the | |
| 142 operands: | |
| 143 | |
| 144 >>> print Element('br') + 'some text' + Element('br') | |
| 145 <br/>some text<br/> | |
| 146 | |
| 147 Elements with a namespace can be generated using the `Namespace` and/or | |
| 148 `QName` classes: | |
| 149 | |
| 150 >>> from markup.core import Namespace | |
| 151 >>> xhtml = Namespace('http://www.w3.org/1999/xhtml') | |
| 152 >>> print Element(xhtml.html, lang='en') | |
| 153 <html lang="en" xmlns="http://www.w3.org/1999/xhtml"/> | |
| 154 """ | |
| 155 __slots__ = ['tag', 'attrib'] | |
| 156 | |
| 157 def __init__(self, tag_, **attrib): | |
| 158 Fragment.__init__(self) | |
| 159 self.tag = QName(tag_) | |
| 160 self.attrib = Attributes() | |
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161 for attr, value in attrib.items(): |
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162 if value is not None: |
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163 if not isinstance(value, basestring): |
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164 value = unicode(value) |
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165 self.attrib.append((QName(attr.rstrip('_').replace('_', '-')), |
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166 value)) |
| 1 | 167 |
| 168 def __call__(self, *args, **kwargs): | |
| 169 for attr, value in kwargs.items(): | |
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170 if value is not None: |
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171 if not isinstance(value, basestring): |
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172 value = unicode(value) |
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173 self.attrib.set(attr.rstrip('_').replace('_', '-'), value) |
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174 Fragment.__call__(self, *args) |
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175 return self |
| 1 | 176 |
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177 def __repr__(self): |
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178 return '<%s "%s">' % (self.__class__.__name__, self.tag) |
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179 |
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180 def _generate(self): |
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181 yield START, (self.tag, self.attrib), (None, -1, -1) |
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182 for kind, data, pos in Fragment._generate(self): |
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183 yield kind, data, pos |
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184 yield END, self.tag, (None, -1, -1) |
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185 |
| 1 | 186 def generate(self): |
| 28 | 187 """Return a markup event stream for the fragment.""" |
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188 return Stream(self._generate()) |
| 1 | 189 |
| 190 | |
| 191 class ElementFactory(object): | |
| 28 | 192 """Factory for `Element` objects. |
| 193 | |
| 194 A new element is created simply by accessing a correspondingly named | |
| 195 attribute of the factory object: | |
| 196 | |
| 197 >>> factory = ElementFactory() | |
| 198 >>> print factory.foo | |
| 199 <foo/> | |
| 200 >>> print factory.foo(id=2) | |
| 201 <foo id="2"/> | |
| 202 | |
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203 Markup fragments (lists of nodes without a parent element) can be created |
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204 by calling the factory: |
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205 |
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206 >>> print factory('Hello, ', factory.em('world'), '!') |
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207 Hello, <em>world</em>! |
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208 |
| 28 | 209 A factory can also be bound to a specific namespace: |
| 210 | |
| 211 >>> factory = ElementFactory('http://www.w3.org/1999/xhtml') | |
| 212 >>> print factory.html(lang="en") | |
| 213 <html lang="en" xmlns="http://www.w3.org/1999/xhtml"/> | |
| 214 | |
| 215 The namespace for a specific element can be altered on an existing factory | |
| 216 by specifying the new namespace using item access: | |
| 217 | |
| 218 >>> factory = ElementFactory() | |
| 219 >>> print factory.html(factory['http://www.w3.org/2000/svg'].g(id=3)) | |
| 220 <html><g id="3" xmlns="http://www.w3.org/2000/svg"/></html> | |
| 221 | |
| 222 Usually, the `ElementFactory` class is not be used directly. Rather, the | |
| 223 `tag` instance should be used to create elements. | |
| 224 """ | |
| 1 | 225 |
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226 def __init__(self, namespace=None): |
| 28 | 227 """Create the factory, optionally bound to the given namespace. |
| 228 | |
| 229 @param namespace: the namespace URI for any created elements, or `None` | |
| 230 for no namespace | |
| 231 """ | |
| 20 | 232 if namespace and not isinstance(namespace, Namespace): |
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233 namespace = Namespace(namespace) |
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234 self.namespace = namespace |
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235 |
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236 def __call__(self, *args): |
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237 return Fragment()(*args) |
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238 |
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239 def __getitem__(self, namespace): |
| 28 | 240 """Return a new factory that is bound to the specified namespace.""" |
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241 return ElementFactory(namespace) |
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242 |
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243 def __getattr__(self, name): |
| 28 | 244 """Create an `Element` with the given name.""" |
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245 return Element(self.namespace and self.namespace[name] or name) |
| 1 | 246 |
| 247 | |
| 248 tag = ElementFactory() |