The prevpage and nextpage attributes generate an href (5.2.6.2) attribute that respectively selects the previous and next pages of an <al-for> ListIterator (5.3.8.8).
The attribute value specifies the name of the iterator.
The generated href attribute is of the form current_url?name,iter=1 where current_url is the path component returned from the Python urlparse.urlparse() function (via the execution context current_url() method), name is either prevpage or nextpage, and iter is the specified iterator.
For example:
>>> import albatross
>>> class Ctx(albatross.SimpleContext):
... def current_url(self):
... return 'magic'
...
>>> ctx = Ctx('.')
>>> albatross.Template(ctx, '<magic>', '''
... <al-a nextpage="m">Next Page</al-a whitespace>
... ''').to_html(ctx)
>>> ctx.flush_content()
<a href="magic?nextpage,m=1">Next Page</a>