  System reuse and cost are very important in software product line design
area. Developers goal is to increase system reuse and decreasing cost and
efforts for building components from scratch for each software configuration.
This can be reached by developing Software Product Line (SPL). To handle SPL
engineering process, several approaches with several techniques were developed.
One of these approaches is called separated approach. It requires separating
the commonalities and variability for system components to allow configuration
selection based on user defined features. Textual notation-based approaches
have been used for their formal syntax and semantics to represent system
features and implementations. But these approaches are still weak in mixing
features (conceptual level) and classes (physical level) that guarantee smooth
and automatic configuration generation for software releases. The absence of
methodology supporting the mixing process is a real weakness. In this paper, we
enhanced SPL reuse by introducing some meta-features, classified according to
their functions. As a first consequence, mixing class and feature concepts is
supported in a simple way using class interfaces and inherent features for
smooth move from feature model to class model. And as a second consequence, the
mixing process is supported by a textual design and implementation methodology,
mixing class and feature models by combining their concepts in a single
language. The supported configuration generation process is simple, coherent,
and complete.
