Building an Abstract Syntax Tree
Currently, our parser interprets the input code and evaluates it in the same pass. Most compilers and interpreters; however, create an intermediate data structure before actually running the program: an Abstract Syntax Tree (AST). Using an AST offers some interesting possibilities; for example, it provides you with a structured representation of your program that you can then analyze. Also, you can use the AST and transform it back into a text-based program (maybe of another language).
An AST is a tree that represents the structure of a program. The first step to building an AST-based parser is to design the tree's object model: which classes are needed and in which way are they associated to another. The following ...
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