Mercurial > genshi > genshi-test
changeset 517:c98e9dcbedbb
More flexible transformation attribute set and delete. Attribute selections are
now marked explicitly in the transform stream.
| author | athomas |
|---|---|
| date | Wed, 06 Jun 2007 17:16:10 +0000 |
| parents | 0e5a25f1b83d |
| children | 97cdadc17e20 |
| files | genshi/filters/transform.py |
| diffstat | 1 files changed, 51 insertions(+), 52 deletions(-) [+] |
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--- a/genshi/filters/transform.py +++ b/genshi/filters/transform.py @@ -51,8 +51,8 @@ from genshi.core import Stream, Attrs, QName, TEXT, START, END, _ensure from genshi.path import Path -__all__ = ['Transformer', 'StreamBuffer', 'InjectorTransformation', 'ENTER', - 'EXIT', 'INSIDE', 'OUTSIDE'] +__all__ = ['Transformer', 'StreamBuffer', 'AttributeBuffer', + 'InjectorTransformation', 'ENTER', 'EXIT', 'INSIDE', 'OUTSIDE'] class TransformMark(str): @@ -76,6 +76,10 @@ """Stream augmentation mark indicating that a match occurred outside a selected element.""" +ATTRIBUTE = TransformMark('ATTRIBUTE') +"""Stream augmentation mark indicating that a an element attribute was +selected.""" + EXIT = TransformMark('EXIT') """Stream augmentation mark indicating that a selected element is being exited.""" @@ -129,7 +133,7 @@ taken when using buffers, to ensure that buffers are cleared between transforms: - >>> emphasis = Transformer('body//em').setattr('class', 'emphasis') + >>> emphasis = Transformer('body//em').attr('class', 'emphasis') >>> print html | emphasis <html><head><title>Some Title</title></head><body>Some <em class="emphasis">body</em> text.</body></html> @@ -398,39 +402,44 @@ #{ Attribute manipulation - def setattr(self, name, value): - """Add or replace an attribute to selected elements. + def attr(self, name, value): + """Add, replace or delete an attribute on selected elements. - Example: + If `value` evaulates to `None` the attribute will be deleted from the + element: >>> html = HTML('<html><head><title>Some Title</title></head>' - ... '<body>Some <em>body</em> text.</body></html>') - >>> print html | Transformer('.//em').setattr('class', 'emphasis') + ... '<body>Some <em class="before">body</em> <em>text</em>.</body>' + ... '</html>') + >>> print html | Transformer('body/em').attr('class', None) + <html><head><title>Some Title</title></head><body>Some <em>body</em> + <em>text</em>.</body></html> + + Otherwise the attribute will be set to `value`: + + >>> print html | Transformer('body/em').attr('class', 'emphasis') <html><head><title>Some Title</title></head><body>Some <em - class="emphasis">body</em> text.</body></html> + class="emphasis">body</em> <em class="emphasis">text</em>.</body></html> + + If `value` is a callable it will be called with the attribute name and + the `START` event for the matching element. Its return value will then + be used to set the attribute: + + >>> def print_attr(name, event): + ... attrs = event[1][1] + ... print attrs + ... return attrs.get(name) + >>> print html | Transformer('body/em').attr('class', print_attr) + Attrs([(QName(u'class'), u'before')]) + Attrs() + <html><head><title>Some Title</title></head><body>Some <em + class="before">body</em> <em>text</em>.</body></html> :param name: the name of the attribute - :param value: the value that should be set for the attribute + :param value: the value that should be set for the attribute. :rtype: `Transformer` """ - return self | SetattrTransformation(name, value) - - def delattr(self, name): - """Remove an attribute from selected elements. - - Example: - - >>> html = HTML('<html><head><title>Some Title</title></head>' - ... '<body>Some <em class="emphasis">body</em> ' - ... 'text.</body></html>') - >>> print html | Transformer('.//*[@class="emphasis"]').delattr('class') - <html><head><title>Some Title</title></head><body>Some <em>body</em> - text.</body></html> - - :param name: the name of the attribute to remove - :rtype: `Transformer` - """ - return self | DelattrTransformation(name) + return self | AttrTransformation(name, value) #{ Buffer operations @@ -581,7 +590,8 @@ else: yield OUTSIDE, event elif result: - yield ENTER, result + yield None, event + yield ATTRIBUTE, result else: yield None, event @@ -852,7 +862,7 @@ yield mark, event -class SetattrTransformation(object): +class AttrTransformation(object): """Set an attribute on selected elements.""" def __init__(self, name, value): @@ -869,32 +879,21 @@ :param stream: The marked event stream to filter """ + callable_value = callable(self.value) for mark, (kind, data, pos) in stream: if mark is ENTER: - data = (data[0], data[1] | [(QName(self.name), self.value)]) + if callable_value: + value = self.value(self.name, (kind, data, pos)) + else: + value = self.value + if value is None: + attrs = data[1] - [QName(self.name)] + else: + attrs = data[1] | [(QName(self.name), value)] + data = (data[0], attrs) yield mark, (kind, data, pos) -class DelattrTransformation(object): - """Delete an attribute of selected elements.""" - - def __init__(self, name): - """Construct transform. - - :param name: the name of the attribute to remove - """ - self.name = name - - def __call__(self, stream): - """Apply the transform filter to the marked stream. - - :param stream: The marked event stream to filter - """ - for mark, (kind, data, pos) in stream: - if mark is ENTER: - data = (data[0], data[1] - self.name) - yield mark, (kind, data, pos) - class StreamBuffer(Stream): """Stream event buffer used for cut and copy transformations.""" @@ -905,7 +904,7 @@ def append(self, event): """Add an event to the buffer. - + :param event: the markup event to add """ self.events.append(event)