A very simple 'skeleton' extension

This sample extension exemplifies an organization that some might find useful in writing language extensions for ableC.

The grammars directory contains all the Silver source of the language extension.

The examples directory demonstrates how to create an ableC compiler using the extension and some sample programs using that extension. This directory contains a script that can be used to compile and run the examples.

The tests directory contains some positive and negative tests of various features of the extension.

Header files containing definitions used by the extension are placed in the include directory.

At the top level, a Makefile is provided to allow examples, modular analyses, and tests to be easily built by running make.

Extension designers are of course free to organize files as they choose. This is simply an example that works well for us.

Modular analysis of language extensions

Silver and Copper provide two modular analyses that provide strong composability guarantees to the programmer using a set of independently-developed language extensions.

Specifically, any set of language extensions that pass the analyses can be automatically composed to form a working compiler.

Each of these analysis are to be run by the extension developer on their extension. If the extension fails to pass the analysis, the extension designer needs to modify the extension specification to make it pass.

The first analysis is the modular determinism analysis and it ensures that the composed specification of the lexical and context-free syntax of ambiguities.

The second is the modular well-definedness analysis. It ensures that the composed attribute grammar is well-defined and thus the semantic analysis and code generation phases will complete successfully.

The make mda and make mwda commands allow the programmer to verify that the extensions do in fact pass these modular analyses.