persistent functional language

1 definition found

persistent functional language - Free On-line Dictionary of Computing (26 May 2007) :

  Persistent Functional Language
  
     <functional language, database> (PFL) A functional database
     language developed by Carol Small at Birkbeck College, London,
     UK and Alexandra Poulovassilis (now at King's College London
     ).
  
     In PFL, functions are defined equationally and bulk data is
     stored using a special class of functions called selectors.
     PFL is a lazy language, supports higher-order functions,
     has a strong polymorphic type inference system, and allows
     new user-defined data types and values.  All functions, types
     and values persist in a database.  Functions can be written
     which update all aspects of the database: by adding data to
     selectors, by defining new equations, and by introducing new
     data types and values.
  
     PFL is "semi-referentially transparent", in the sense that
     whilst updates are referentially opaque and are executed
     destructively, all evaluation is referentially transparent.
     Similarly, type checking is "semi-static" in the sense that
     whilst updates are dynamically type checked at run time,
     expressions are type checked before they are evaluated and no
     type errors can occur during their evaluation.
  
     ["A Functional Approach to Database Updates  (http://web.dcs.bbk.ac.uk/CS/Research/DBPL/papers/INFSYS93.abs.html)
      ",
     C. Small, Information Systems 18(8), 1993, pp. 581-95].
  
     (1995-04-27)