xfpt is a program that reads a marked-up ASCII source file, and
converts it into XML. It was written with DocBook XML in mind, but
can also be used for other forms of XML. Unlike AsciiDoc, xfpt does
not try to produce XML from a document that is also usable as a
freestanding ASCII document. The input for xfpt is very definitely
"marked up". This makes it less ambiguous for large and/or complicated
documents. xfpt is also much faster than AsciiDoc because it is
written in C and does not rely on pattern matching.

Homepage:
http://quercite.dx.am/
