genshi.builder

Package genshi :: Module builder |

# Module builder

Support for programmatically generating markup streams from Python code using a very simple syntax. The main entry point to this module is the tag object (which is actually an instance of the `ElementFactory` class). You should rarely (if ever) need to directly import and use any of the other classes in this module.

Elements can be created using the tag object using attribute access. For example:

    >>> doc = tag.p('Some text and ', tag.a('a link', href='http://example.org/'), '.')
    >>> doc
    <Element "p">

This produces an Element instance which can be further modified to add child nodes and attributes. This is done by "calling" the element: positional arguments are added as child nodes (alternatively, the Element.append method can be used for that purpose), whereas keywords arguments are added as attributes:

    >>> doc(tag.br)
    <Element "p">
    >>> print(doc)
    <p>Some text and <a href="http://example.org/">a link</a>.<br/></p>

If an attribute name collides with a Python keyword, simply append an underscore to the name:

    >>> doc(class_='intro')
    <Element "p">
    >>> print(doc)
    <p class="intro">Some text and <a href="http://example.org/">a link</a>.<br/></p>

As shown above, an Element can easily be directly rendered to XML text by printing it or using the Python `str()` function. This is basically a shortcut for converting the Element to a stream and serializing that stream:

    >>> stream = doc.generate()
    >>> stream #doctest: +ELLIPSIS
    <genshi.core.Stream object at ...>
    >>> print(stream)
    <p class="intro">Some text and <a href="http://example.org/">a link</a>.<br/></p>

The tag object also allows creating "fragments", which are basically lists of nodes (elements or text) that don't have a parent element. This can be useful for creating snippets of markup that are attached to a parent element later (for example in a template). Fragments are created by calling the tag object, which returns an object of type Fragment:

    >>> fragment = tag('Hello, ', tag.em('world'), '!')
    >>> fragment
    <Fragment>
    >>> print(fragment)
    Hello, <em>world</em>!

Classes
| Fragment Represents a markup fragment, which is basically just a list of element or text nodes.
| Element Simple XML output generator based on the builder pattern.
| ElementFactory Factory for Element objects.

Variables
ElementFactory | tag = `ElementFactory()` Global ElementFactory bound to the default namespace.