Use parameterization to reflect contextual variablity.

• Whenever possible, reuse high-level code rather than writing it differently for each context.
• ``Over'' generalizations can impede understandability. But cures exist: e.g., provide partial instantiations.
• Focus on type composibility to relate different parameterized entities.
• Common cases:

                       |   Entity   | Entity Generator
          --------------------------------------------
          Object       | constructor| type arguments to 
                       |  arguments |  templates or generics
          --------------------------------------------
          Service      | control    |  procedure
                       | arguments  |  arguments
  

• Can express via conditional compilation and run-time conditions when you have a finite number of combinations.
• Can use generative macros.
• Can use late binding and polymorphism.
• Can use stand-alone tools that escape limitations of programming languages. (e.g., cannot define a parameterized construct that generates templates in C++, so need a tool.)
• For full generality, need a meta-circular evaluator (e.g.,LISP)