While using PyHAML to build an app with AngularJS, I noticed that some of my attributes were being "sanitized" when I use a `def` or `block` tag with HAML syntax (e.g. `%%self:some_def` below). The PyHAML preprocessor expands the attribute name on the tag to `ng-app`, then Mako barfs on the `ng-` prefix of the attribute. Woes!

borked.haml

- attrs={ "ngApp": "something" }
%p(**attrs)
  This element should have an attribute <code>ng-app="something"</code>. |
  It works just fine.

%%(def(name="some_def(**attrs)")
  = attrs
  %p(**attrs)
    = caller.body() or 'Cannot pass a body to a function... :/'

${some_def(ngApp="something")
  I can't pass a body with this invocation, can I...?

%%self:some_def(ngApp="something")
  This element should have an attribute <code>ng-app="something"</code>, too. |
  But something went wrong.

borked.mako

<%! from haml import runtime as __HAML %>
<%
attrs={ "ngApp": "something" }
%>
<p<% __M_writer(__HAML.attribute_str(**attrs)) %>>
    This element should have an attribute <code>ng-app="something"</code>.
    It works just fine.
</p>
<%def name="some_def(**attrs)">
    ${attrs}
    <p<% __M_writer(__HAML.attribute_str(**attrs)) %>>
        ${caller and caller.body()}
    </p>
</%def>
${some_def(ngApp="something")}
    I can't pass a body with this invocation, can I...?
<%self:some_def ng-app="something">
    This element should have an attribute <code>ng-app="something"</code>, too.
    But something went wrong.
</%self:some-def>

borked.sh

Traceback (most recent call last):
. . .
mako.exceptions.SyntaxException: Expected %> at line: 18 char: 53

It has been released to PyPI as v0.1.9.

Cheers!