Integrate with Java
We have seen meso: and imop: UTLs in previous examples. Here we import a java: UTL to locate a Java class, and use it as if it is native to the Meso language. This allows a Meso program to work with existing Java code. When compiling the source code, tasks related to the Java UTLs, such as type reflection and code generation, are delegated to a Java scheme plugin in the Meso compiler. Like the meso: scheme, a java: UTL does not have an authority host portion either. It will only locate the Java class reachable by the local JVM.
Type scheme plugins enable external resources to be integrated more tightly with the language. A plugin can present an external resource as a regular object or an abstract type definition in Meso, and handle the underlying mechanisms or protocols needed behind the scene. For example, one may create a http: plugin so that a web page can be imported with the page's HTTP URL. The plugin can make the remote page appear to be a singleton object that has get(), post(), put(), and delete() methods corresponding to the HTTP methods. How an external resource appears in the Meso language is completely up to the plugin's design.