View source for Fold()

FOLD()

  FUNCTION: fold([<obj>/]<attr>, <list>[, <base-case>[, <delim>])

  This function iteratively processes a list through a function, feeding
  the result of one step into the next step as %0, passing in the next element
  from the list as %1.

  If a base case is provided, it is used as the initial %0.  If not, the first
  list element is passed as %0 and the second is passed as %1, and subsequent
  iterations proceed normally.

  <delimiter> may be used to specify a delimiter other than space, but you
  must specify a base case in order to specify the delimiter.

  Examples:
    > &REP_NUM object=[%0][repeat(%1,%1)]
    > say fold(object/rep_num,1 2 3 4 5,->)
    You say, "->122333444455555"
    > &ADD_NUMS object=add(%0,%1)
    > say fold(object/add_nums,1 2 3 4 5)
    You say, "15"

  Related Topics: u(), iter(), map(), filter()