FOSD metamodels

Feature Oriented Software Development (FOSD) is a general paradigm for software generation, where a model of a product line is a tuple of 0-ary and 1-ary functions (program transformations). This page discusses a more abstract concept of models of product lines of product lines (PL**2) called metamodels, and product lines of product lines of product lines called meta-metamodels (PL**3), and further abstract concepts.

Metamodels

A metamodel is a model whose instances are models.[1] A GenVoca model of a product line is a tuple whose components are features (0-ary or 1-ary functions). An extension (a.k.a. delta or refinement) of a model is a "meta-feature", which is a tuple of deltas that can modify an existing product line by modifying existing features and adding new features. As a simple example, consider GenVoca model M that contains three features a-c:

${\displaystyle M=[a,b,c]}$

Suppose meta-model MM contains three meta-features AAA-CCC, each of which is a tuple with a single non-identity feature:

${\displaystyle {\begin{array}{lcl}MM=[AAA,BBB,CCC]\\\ \ \ \ \ \ \ \ =[[a,0,0],[0,b,0],[0,0,c]]\end{array}}}$

where 0 is the null feature. Model M is constructed by adding the meta-features of MM, where + is the composition operation (see FOSD).

${\displaystyle {\begin{array}{lcl}M=AAA+BBB+CCC\qquad \qquad {\text{ -- expression}}\\\quad \ =[a,0,0]+[0,b,0]+[0,0,c]\qquad {\text{ -- substitution}}\\\quad \ =[a+0+0,0+b+0,0+0+c]{\text{ -- composition}}\\\quad \ =[a,b,c]\qquad \qquad \qquad \qquad \qquad \ {\text{ -- simplification where 0+x=x+0=x}}\end{array}}}$

MM models a product line of product lines (PL**2). That is, different MM expressions correspond to GenVoca models of different product lines..

Applications

• AHEAD Tool Suite and Extensible Java Preprocessors
• SVG Applications
• Expression Problem or the Extensibility Problem
• Multi-Dimensional Separation of Concerns

See also

• Feature Oriented Programming—basic overview
• FOSD origami
• FOSD Program Cubes—multi-dimensional product lines
• FOSD Feature Interactions—other operations on features, including an operation designating feature interaction

References

1. "Scaling Step-Wise Refinement" (PDF).