The Mathematica module provides an interface to the MathLink(TM) library. Functions are not exported and should be called as methods. Therefore the Perl names have the 'ML' prefix stripped. Since Perl can handle multiple return values, methods fetching elements from the link return the values instead of passing results in reference parameters.
The representation of the data passed between Perl and Mathematica is straight forward exept the symbols which are represented as blessed scalars in Perl.