Application Software, Domain-Specific Languages, and Language Design   Assistants
  While application software does the real work, domain-specific languages (DSLs) are tools to help produce it efficiently, and language design assistants in turn are meta-tools to help produce DSLs quickly. DSLs are already in wide use (HTML for web pages, Excel macros for spreadsheet applications, VHDL for hardware design, ...), but many more will be needed for both new as well as existing application domains. Language design assistants to help develop them currently exist only in the basic form of language development systems. After a quick look at domain-specific languages, and especially their relationship to application libraries, we survey existing language development systems and give an outline of future language design assistants. 
Jan Heering