Description:

• readxml(filename) reads the first occurrence of a lambda application with one bounded variable on applications of the supported basic functions in file filename and returns it as a Sollya functional expression.
  
  If the file filename does not contain a valid MathML-Content tree, readxml tries to find an "annotation encoding" markup of type "sollya/text". If this annotation contains a character sequence that can be parsed by parse, readxml returns that expression. Otherwise readxml displays a warning and returns an error variable of type error.