build2-dynamic-target-group-demo

This project contains a bunch of (hypothetical) source code generation tools and a build system module that demonstrate handling of dynamic target groups in build2 where the number and the names of group members (source files in this case) cannot be predicted.

Specifically, it contains the exe-generator and exe-compiler tools, the libbuild2-compiler build system modules, and the exe-consumer test project. These should be initialized as described in libbuild2-hello (tools in the host configuration, module -- in build2, and test -- in target).

The expected tools invocation sequence is as follows:

1. First we must call generator in order to obtain a cookie.

   A previously-obtained cookie is valid as long as the generator hasn't changed.

2. Then we call compiler with the --list-source-files option passing it the cookie. The result is a list of header/source files (written to stdout) that will be generated for this cookie. The number and names of the files depend on the cookie.

   A previously-obtained list for the same cookie is valid as long as the compiler hasn't changed.

3. Finally, we call compiler with the --output-dir <dir> option passing it the cookie. The result is the set of generated files written to <dir>.

   A previously-generated set of files for the same cookie is valid as long as the compiler hasn't changed.

All these steps and associated change tracking is handled by the rule in the libbuild2-compiler module. The dynamic set of the generated source files is represented with the compiler.generated{} target group. See exe-consumer/buildfile for usage examples.