====================
BeautifulSoup Parser
====================

:Author:
  Stefan Behnel

BeautifulSoup_ is a Python package that parses broken HTML.  While libxml2
(and thus lxml) can also parse broken HTML, BeautifulSoup is much more
forgiving and has superiour `support for encoding detection`_.

.. _BeautifulSoup: http://www.crummy.com/software/BeautifulSoup/
.. _`support for encoding detection`: http://www.crummy.com/software/BeautifulSoup/documentation.html#Beautiful%20Soup%20Gives%20You%20Unicode,%20Dammit

lxml can benefit from the parsing capabilities of BeautifulSoup through the
`lxml.html.ElementSoup` module.  It provides two main functions: `parse()` to
parse a file using BeautifulSoup, and `convert_tree()` to convert a
BeautifulSoup tree into a list of top-level Elements.

Here is a document full of tag soup, similar to, but not quite like, HTML::

    >>> tag_soup = '<meta><head><title>Hello</head<body onload=crash()>Hi all<p>'

all you need to do is pass it to the `parse()` function::

    >>> from lxml.html.ElementSoup import parse
    >>> from StringIO import StringIO
    >>> root = parse(StringIO(tag_soup))

To see what we have here, you can serialise it::

    >>> from lxml.etree import tostring
    >>> print tostring(root, pretty_print=True),
    <html>
      <meta/>
      <head>
        <title>Hello</title>
      </head>
      <body onload="crash()">Hi all<p/></body>
    </html>

Not quite what you'd expect from an HTML page, but, well, it was broken
already, right?  BeautifulSoup did its best, and so now it's a tree.

To control which Element implementation is used, you can pass a
``makeelement`` factory function to ``parse()``. By default, this is based on
the HTML parser defined in ``lxml.html``.
