4.4 Extending Rscons

4.4.1 Adding New Languages

The Object and SharedObject builders that ship with Rscons have an API that allows the user to register extra languages that can be suppored by the builders. In fact, the built-in support for assembly, C, C++, and D compilation all make use of this built-in API. To see an example of how this API is used, see the lib/rscons/builders/lang/*.rb files in the Rscons source repository. For example, here is how the C++ language is registered:

Rscons::Builders::Object.register(command: "${CXXCMD}", direct_command: "${CXXCMD:direct}", suffix: "${CXXSUFFIX}", preferred_ld: "${CXX}")
Rscons::Builders::SharedObject.register(command: "${SHCXXCMD}", direct_command: "${SHCXXCMD:direct}", suffix: "${CXXSUFFIX}", preferred_ld: "${SHCXX}")

There are also default construction variables registered to go along with the language registration as specified above. New default construction variables can be registered globally by assigning to the Rscons::DEFAULT_CONSTRUCTION_VARIABLES Hash. For example:

Rscons::DEFAULT_CONSTRUCTION_VARIABLES["CXXCMD"] = %w[${CXX} -c -o ${_TARGET} ${CXXDEPGEN} ${INCPREFIX}${CPPPATH} ${CPPFLAGS} ${CXXFLAGS} ${CCFLAGS} ${_SOURCES}]