A generator of efficient strongly typed abstract syntax trees in Java

Abstract syntax trees are a very common data-structure in language related tools. For example compilers, interpreters, documentation generators, and syntax-directed editors use them extensively to extract, transform, store and produce information that is key to their functionality. We present a Java back-end for ApiGen, a tool that generates implementations of abstract syntax trees. The generated code is characterized by strong typing combined with a generic interface and maximal sub-term sharing for memory efficiency and fast equality checking. The goal of this tool is to obtain safe and efficient programming interfaces for abstract syntax trees. The contribution of this work is the combination of generating a strongly typed data-structure with maximal sub-term sharing in Java. Practical experience shows that this approach can not only be used for tools that are otherwise manually constructed, but also for internal data-structures in generated tools.