Mercurial > genshi > mirror
annotate markup/builder.py @ 48:a5d585dd38c4 trunk
convert the result of expressions in attributes to strings so that values like ints are output correctly
| author | mgood |
|---|---|
| date | Tue, 04 Jul 2006 04:49:22 +0000 |
| parents | 3421dd98f015 |
| children | b3fdf93057ab |
| rev | line source |
|---|---|
| 1 | 1 # -*- coding: utf-8 -*- |
| 2 # | |
| 3 # Copyright (C) 2006 Christopher Lenz | |
| 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 | |
| 27 | 8 # are also available at http://markup.cmlenz.net/wiki/License. |
| 1 | 9 # |
| 10 # This software consists of voluntary contributions made by many | |
| 11 # individuals. For the exact contribution history, see the revision | |
| 27 | 12 # history and logs, available at http://markup.cmlenz.net/log/. |
| 1 | 13 |
|
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704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
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changeset
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14 from markup.core import Attributes, Namespace, QName, Stream |
| 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 | |
| 28 def append(self, node): | |
| 29 """Append an element or string as child node.""" | |
| 30 if isinstance(node, (Element, basestring, int, float, long)): | |
| 31 # For objects of a known/primitive type, we avoid the check for | |
| 32 # whether it is iterable for better performance | |
| 33 self.children.append(node) | |
| 34 elif isinstance(node, Fragment): | |
| 35 self.children += node.children | |
| 36 elif node is not None: | |
| 37 try: | |
| 38 children = iter(node) | |
| 39 except TypeError: | |
| 40 self.children.append(node) | |
| 41 else: | |
| 42 for child in node: | |
| 43 self.append(children) | |
| 44 | |
| 45 def __add__(self, other): | |
| 46 return Fragment()(self, other) | |
| 47 | |
| 48 def __call__(self, *args): | |
| 49 for arg in args: | |
| 50 self.append(arg) | |
| 51 return self | |
| 52 | |
| 53 def generate(self): | |
| 28 | 54 """Return a markup event stream for the fragment.""" |
| 1 | 55 def _generate(): |
| 56 for child in self.children: | |
| 57 if isinstance(child, Fragment): | |
| 58 for event in child.generate(): | |
| 59 yield event | |
| 60 else: | |
|
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74cc70129d04
Refactoring to address #6: all match templates are now processed by a single filter, which means that match templates added by included templates are properly applied. A side effect of this refactoring is that `Context` objects may not be reused across multiple template processing runs.
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61 yield Stream.TEXT, unicode(child), (-1, -1) |
| 1 | 62 return Stream(_generate()) |
| 63 | |
| 64 def __iter__(self): | |
| 65 return iter(self.generate()) | |
| 66 | |
| 67 def __str__(self): | |
| 68 return str(self.generate()) | |
| 69 | |
| 70 def __unicode__(self): | |
| 71 return unicode(self.generate()) | |
| 72 | |
| 73 | |
| 74 class Element(Fragment): | |
| 75 """Simple XML output generator based on the builder pattern. | |
| 76 | |
| 77 Construct XML elements by passing the tag name to the constructor: | |
| 78 | |
| 79 >>> print Element('strong') | |
| 80 <strong/> | |
| 81 | |
| 82 Attributes can be specified using keyword arguments. The values of the | |
| 83 arguments will be converted to strings and any special XML characters | |
| 84 escaped: | |
| 85 | |
| 86 >>> print Element('textarea', rows=10, cols=60) | |
| 87 <textarea rows="10" cols="60"/> | |
| 88 >>> print Element('span', title='1 < 2') | |
| 89 <span title="1 < 2"/> | |
| 90 >>> print Element('span', title='"baz"') | |
| 91 <span title=""baz""/> | |
| 92 | |
| 93 The " character is escaped using a numerical entity. | |
| 94 The order in which attributes are rendered is undefined. | |
| 95 | |
| 96 If an attribute value evaluates to `None`, that attribute is not included | |
| 97 in the output: | |
| 98 | |
| 99 >>> print Element('a', name=None) | |
| 100 <a/> | |
| 101 | |
| 102 Attribute names that conflict with Python keywords can be specified by | |
| 103 appending an underscore: | |
| 104 | |
| 105 >>> print Element('div', class_='warning') | |
| 106 <div class="warning"/> | |
| 107 | |
| 108 Nested elements can be added to an element using item access notation. | |
| 109 The call notation can also be used for this and for adding attributes | |
| 110 using keyword arguments, as one would do in the constructor. | |
| 111 | |
| 112 >>> print Element('ul')(Element('li'), Element('li')) | |
| 113 <ul><li/><li/></ul> | |
| 114 >>> print Element('a')('Label') | |
| 115 <a>Label</a> | |
| 116 >>> print Element('a')('Label', href="target") | |
| 117 <a href="target">Label</a> | |
| 118 | |
| 119 Text nodes can be nested in an element by adding strings instead of | |
| 120 elements. Any special characters in the strings are escaped automatically: | |
| 121 | |
| 122 >>> print Element('em')('Hello world') | |
| 123 <em>Hello world</em> | |
| 124 >>> print Element('em')(42) | |
| 125 <em>42</em> | |
| 126 >>> print Element('em')('1 < 2') | |
| 127 <em>1 < 2</em> | |
| 128 | |
| 129 This technique also allows mixed content: | |
| 130 | |
| 131 >>> print Element('p')('Hello ', Element('b')('world')) | |
| 132 <p>Hello <b>world</b></p> | |
| 133 | |
| 34 | 134 Quotes are not escaped inside text nodes: |
| 135 >>> print Element('p')('"Hello"') | |
| 136 <p>"Hello"</p> | |
| 137 | |
| 1 | 138 Elements can also be combined with other elements or strings using the |
| 139 addition operator, which results in a `Fragment` object that contains the | |
| 140 operands: | |
| 141 | |
| 142 >>> print Element('br') + 'some text' + Element('br') | |
| 143 <br/>some text<br/> | |
| 144 | |
| 145 Elements with a namespace can be generated using the `Namespace` and/or | |
| 146 `QName` classes: | |
| 147 | |
| 148 >>> from markup.core import Namespace | |
| 149 >>> xhtml = Namespace('http://www.w3.org/1999/xhtml') | |
| 150 >>> print Element(xhtml.html, lang='en') | |
| 151 <html lang="en" xmlns="http://www.w3.org/1999/xhtml"/> | |
| 152 """ | |
| 153 __slots__ = ['tag', 'attrib'] | |
| 154 | |
| 155 def __init__(self, tag_, **attrib): | |
| 156 Fragment.__init__(self) | |
| 157 self.tag = QName(tag_) | |
| 158 self.attrib = Attributes() | |
| 159 self(**attrib) | |
| 160 | |
| 161 def __call__(self, *args, **kwargs): | |
| 162 for attr, value in kwargs.items(): | |
| 163 if value is None: | |
| 164 continue | |
| 165 attr = attr.rstrip('_').replace('_', '-') | |
| 166 self.attrib.set(attr, value) | |
| 167 return Fragment.__call__(self, *args) | |
| 168 | |
| 169 def generate(self): | |
| 28 | 170 """Return a markup event stream for the fragment.""" |
| 1 | 171 def _generate(): |
| 172 yield Stream.START, (self.tag, self.attrib), (-1, -1) | |
| 173 for kind, data, pos in Fragment.generate(self): | |
| 174 yield kind, data, pos | |
| 175 yield Stream.END, self.tag, (-1, -1) | |
| 176 return Stream(_generate()) | |
| 177 | |
| 178 | |
| 179 class ElementFactory(object): | |
| 28 | 180 """Factory for `Element` objects. |
| 181 | |
| 182 A new element is created simply by accessing a correspondingly named | |
| 183 attribute of the factory object: | |
| 184 | |
| 185 >>> factory = ElementFactory() | |
| 186 >>> print factory.foo | |
| 187 <foo/> | |
| 188 >>> print factory.foo(id=2) | |
| 189 <foo id="2"/> | |
| 190 | |
| 191 A factory can also be bound to a specific namespace: | |
| 192 | |
| 193 >>> factory = ElementFactory('http://www.w3.org/1999/xhtml') | |
| 194 >>> print factory.html(lang="en") | |
| 195 <html lang="en" xmlns="http://www.w3.org/1999/xhtml"/> | |
| 196 | |
| 197 The namespace for a specific element can be altered on an existing factory | |
| 198 by specifying the new namespace using item access: | |
| 199 | |
| 200 >>> factory = ElementFactory() | |
| 201 >>> print factory.html(factory['http://www.w3.org/2000/svg'].g(id=3)) | |
| 202 <html><g id="3" xmlns="http://www.w3.org/2000/svg"/></html> | |
| 203 | |
| 204 Usually, the `ElementFactory` class is not be used directly. Rather, the | |
| 205 `tag` instance should be used to create elements. | |
| 206 """ | |
| 1 | 207 |
|
19
704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
17
diff
changeset
|
208 def __init__(self, namespace=None): |
| 28 | 209 """Create the factory, optionally bound to the given namespace. |
| 210 | |
| 211 @param namespace: the namespace URI for any created elements, or `None` | |
| 212 for no namespace | |
| 213 """ | |
| 20 | 214 if namespace and not isinstance(namespace, Namespace): |
|
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704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
17
diff
changeset
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215 namespace = Namespace(namespace) |
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704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
17
diff
changeset
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216 self.namespace = namespace |
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704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
17
diff
changeset
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217 |
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704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
17
diff
changeset
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218 def __getitem__(self, namespace): |
| 28 | 219 """Return a new factory that is bound to the specified namespace.""" |
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cmlenz
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changeset
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220 return ElementFactory(namespace) |
|
704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
17
diff
changeset
|
221 |
|
704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
17
diff
changeset
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222 def __getattr__(self, name): |
| 28 | 223 """Create an `Element` with the given name.""" |
|
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704f10b06507
Enable `ElementFactory` to create namespaced elements.
cmlenz
parents:
17
diff
changeset
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224 return Element(self.namespace and self.namespace[name] or name) |
| 1 | 225 |
| 226 | |
| 227 tag = ElementFactory() |