The ProfessorJ Java + dynamic extends Java with a new type keyword, dynamic, and the ability to directly import libraries written in Scheme as well as Java.

The paper Fine Grained Interoperability through Mirrors and Contracts presents the full details of this extension.

Importing Scheme libraries

In the Java + dynamic language, the import statement

import scheme.lib.mred.mred;

directs the compiler to allow the current program to use values provided by the PLT library collection mred.ss located in the mred directory.

The import statement

import scheme.interp.scripts;

directs the compiler to allow the current program to use values provided by the script.ss module located in the interp directory, found using the standard classpath.

Within the body of the Java program, a Scheme value is accessed using the same style as a static member of a class (where a module is seen as a class).

So,

mred.frameObj

in a program importing MrEd allows the Java programmer to access the class of the MrEd library. Within the Java program, this value carries no static type information and can legally appear in any Java value context. During execution, dynamic checks will ensure that Java type guarantees are not violated.

Scheme functions and methods may be called within the Java program, and Java values may be passed in as arguments,

scripts.buildTaxEnv(new TaxCalc())

The Java value is embedded within a contract that ensures Java type guarantees are not violated when the Scheme program accesses the Java value.

Using dynamic

In Java + dynamic, any position that expects a type (except an instanceof expression) can have the type dynamic as well as the original Java types. Such a declaration ensures that no static errors may arise due to the use of the value with this specified type. Any necessary checks to ensure Java's other static type guarantees will be performed at run time.

TODO

Java Values within Scheme

TODO

A Matter of Names

TODO

Java + dynamic and the Teaching languages

TODO