[Zope-CMF] Historical revisions: Enabling page comparisons

[Ausum Studio]

Once that we allow PortalContent to inherit from the History module, there
comes up the issue of enabling comparisons between different revisions. At
this moment it isn't possible with the existing methods, but I guess that is
because the portal objects doesn't store the text in a single "document
source" attribute.

Nonetheless, although we suceeded at allowing the standard comparison
methods to compare "Editable bodies" only, we would have the problem that
that type of comparisons (at html level) aren't friendly to content
maintainers, as they don't neccesarily care about html tags. So we would
need an html-aware comparison engine that would render the latter of the
compared pages, but with differences highlighted; and if it was the case,
indications where strings are missing; just like Google highlights our query
words in "cached".

Are there python modules aimed to perform this? If not, where would you
start to provide this type of functionality to the CMF?


Ausum