tuple

2 definitions found

tuple - Free On-line Dictionary of Computing (26 May 2007) :

  tuple
  
     In functional languages, a data object containing two or
     more components.  Also known as a product type or pair,
     triple, quad, etc.  Tuples of different sizes have different
     types, in contrast to lists where the type is independent of
     the length.  The components of a tuple may be of different
     types whereas all elements of a list have the same type.
     Examples of tuples in Haskell notation are (1,2),
     ("Tuple",True), (w,(x,y),z).  The degenerate tuple with zero
     components, written (), is known as the unit type since it has
     only one possible value which is also written ().
  
     The implementation of tuples in a language may be either
     "lifted" or not.  If tuples are lifted then (bottom,bottom)
     /= bottom and the evaluation of a tuple may fail to terminate.
     E.g. in Haskell:
  
     	f (x,y) = 1    -->    f bottom = bottom
     			      f (bottom,bottom) = 1
  
     With lifted tuples, a tuple pattern is refutable.  Thus in
     Haskell, pattern matching on tuples is the same as pattern
     matching on types with multiple constructors (algebraic data types
     ) - the expression being matched is evaluated as far as
     the top level constructor, even though, in the case of tuples,
     there is only one possible constructor for a given type.
  
     If tuples are unlifted then (bottom, bottom) = bottom and
     evaluation of a tuple will never fail to terminate though any
     of the components may.  E.g. in Miranda:
  
     	f (x,y) = 1    -->    f bottom = 1
     			      f (bottom,bottom) = 1
  
     Thus in Miranda, any object whose type is compatible with a
     tuple pattern is assumed to match at the top level without
     evaluation - it is an irrefutable pattern.  This also
     applies to user defined data types with only one constructor.
     In Haskell, patterns can be made irrefutable by adding a "~"
     as in
  
     	f ~(x,y) = 1.
  
     If tuple constructor functions were strict in all their
     arguments then (bottom,x) = (x,bottom) = bottom for any x so
     matching a refutable pattern would fail to terminate if any
     component was bottom.
  

  TUPLE
  
     Toyohashi University Parallel Lisp Environment.  A parallel
     Lisp based on KCL.
  
     ["Memory Management and Garbage Collection of an Extended
     Common Lisp System for Massively Parallel SIMD Architecture",
     Taiichi Yuasa, in Memory Management, IWMM92, Springer 1992,
     490-507].
  
     (1994-11-08)