2941	 Early Experience with Mesa	 The experiences of Mesa s first users-primarily its implementers-are discussed and some implications for Mesa and similar programming languages are suggested. The specific topics addressed are module structure and its use in defining abstractions data-structuring facilities in Mesa an equivalence algorithm for types and type coercions the benefits of the type system and why it is breached occasionally and the difficulty of making the treatment of variant records safe. programming languages types modules data structures systems programming
