OCaml library that implements an XML-1.0 validating parser

 PXP is a validating parser for XML-1.0 which has been written entirely
 in Objective Caml.
 .
 PXP is the new name of the parser formerly known as "Markup". PXP means
 "Polymorphic XML parser" and emphasizes its most useful property: that
 the API is polymorphic and can be configured such that different objects
 are used to store different types of elements.