1. In a program development environment, a computer implemented method comprising: providing, via a programming language, a language processor with built-in support for a parse tree data structure written in a base language, said parse tree data structure represented as a class, said class being a basis for a plurality of parse tree objects, said parse tree objects including methods that retrieve values for base language objects; defining an assignment function, said assignment function taking a plurality of parse tree structures as arguments; defining said assignment function in more than one class, wherein said assignment function is used to identify in-place operations by examining a type of operator at a root of said parse tree structures; overloading said assignment function based on a context of said base language objects; and calling said assignment function from said language processor to determine a value of at least one assignment within at least one of said base language and a base language extension to said base language.