Metaprogramming Languages

Introduction to Metaprogramming Languages

A metaprogram is a program that manipulates other programs (or itself) as its data. The canonical example is a compiler.

The basic problem is that any general-purpose programming language without a metaprogramming model that is designed to be as pleasant and expressive as the language itself will eventually frustrate the user with it's limitations. No-one can design the perfect language, and yet allowing users to extend the language in generic ways is avoided with a BondageAndDiscipline mentality

Examples of metaprograms are

• the compiler or interpreter of your favourite language
• Lex and Yacc
• CORBA's IDL compiler
• a Quine
• Programs to generate EJB code and XML from database metadata
• Using an {"Eval"} function in dynamic languages to execute a generated string as programming code