Macros That Play: Migrating from Java to Maya

Maya is a version of Java that allows users to write their own syntax extensions, which are called Mayans. Mayans can reinterpret or extend Maya syntax by expanding it to other Maya syntax: they operate on abstract syntax trees, and their expansion is triggered during parsing as semantic actions. Maya’s expressiveness comes from treating grammar productions as generic functions, and Mayans as multimethods on those generic functions. Mayans are defined using a rich set of parameter specializers: Mayans can be dispatched on type of an AST node, the static type of an expression, the value of a token, or the substructure of any AST node. Multiple dispatch allows users to extend the semantics of the language by overriding the language’s base actions. This thesis explores explores the design and implementation space for compiletime meta-programming systems through Maya. Maya uses multiple-dispatch to provide an expressive meta-programming environment. Maya also uses novel implementation techniques to statically detect certain errors in code that builds syntax trees. We use MultiJava (described at OOPSLA 2000) as an example of the syntax and semantics extensions that can be expressed in Maya.