catflap.org Online Dictionary Query

  tupling
       
          A program transformation where several results are returned
          from a single traversal of a data structure.  E.g.
       
          	mean l = sum l / length l
       
          		==>
       
          	mean l = s/n
          		 where
          		 (s,n) = sumLen l
       
          	sumLen []     = (0,0)
          	sumLen (x:xs) = (s+x, n+1)
          			where
          			(s,n) = sumLen xs
       
          In procedural languages this technique is known as
          horizontal loop combination because it uses one loop to
          calculate several results.
       
          Another form of tupling transformation is used to avoid
          repeated evaluation where a function generates several
          identical calls to itself.  By analysing the pattern of
          recursion (see descent function) it is possible to arrange
          for these identical calls to share results.  E.g.
       
          	fib 0 = 1
          	fib 1 = 1
          	fib n = fib (n-1) + fib (n-2)
       
          		==>
       
          	fib n = v where (_,v) = fibt n
          	fibt 0 = (1,1)
          	fibt n = (u+v,u) where (u,v) = fibt (n-1)
       
          (1995-01-12)
       
       

  Tupling
     n.
     (surname: en).

  Tupling
     n.
     (surname: en).

  Tupling
     n.
     (surname: en).

  Tupling
     n.
     (surname: en).