Here is an object oriented version of the infix to postfix converter written in Marvin:
# infixoop.mar | Converts an infix expression into postfix
# This implementation uses the object data as a hash-table
# for operator precedence.
"listop forth dequeop" use
@@Infix
@new # define the hash-table for operator precedence
FALSE ^++ ^+- ^-+ ^-- ^*+ ^*- ^** ^*/ ^/+ ^/- ^/* ://
TRUE ^+* ^+/ ^-* :-/ me ;
@|> & pushfrom ;
@string dfront NONE