The Style API of Pybtex

Rich text

Pybtex was designed to be able to output bibliographies in multiple formats. It means that bibliograhy formatting functions can't just return things like \emph{editor} or <i>journal</i>. We have a simple language for producing formatted text:

>>> from pybtex.richtext import Text, Tag
>>> from pybtex.backends import latex, html
>>> text = Text('This is an example of a ', Tag('emph', 'rich'), ' text.')
>>> print text.render(html.Writer())
This is an example of a <em>rich</em> text.
>>> print text.render(latex.Writer())
This is an example of a \emph{rich} text.

Template language

BibTeX users probably know that it has a simple stack oriented language for defining bibliography styles. That is what is placed inside of .bst files. For a Pythonic bibliography processor it is natural to use Python for writing styles. A Pybtex style file is basically a Python module containing a class named Formatter. This class has methods like format_article, format_book, etc. They accept a bibliography entry (an instance of pybtex.core.Entry class) and return a formatted entry (an instance of pybtex.richtes.Text).

To make things easier we designed a simple template language:

from pybtex.style.formatting import FormatterBase, toplevel
from pybtex.style.template import field, join, optional

class Formatter(FormatterBase):
    def format_article(self, entry):
        if entry.fields['volume']:
            volume_and_pages = join [field('volume'), optional [':', pages]]
        else:
            volume_and_pages = words ['pages', optional [pages]]
        template = toplevel [
            self.format_names('author'),
            sentence [field('title')],
            sentence [
                tag('emph') [field('journal')], volume_and_pages, date],
        ]
        return template.format_data(e)

Is that all?

More documentation will be written when our style API gets some form. Use the source for now.