NAME

       Array::fold - Fold an array.

SYNOPSIS

       b fold( b(a, b) f, [a] xs, b acc )

ARGUMENTS

       f The function to use

       xs The array

       acc The initial value for folding.

DESCRIPTION

       Applies a function across an array. For example, given a function sum which adds two integers:

    total = fold(sum,[1,2,3,4,5],0);
    putStrLn(String(total));

       This prints the sum of the values in the array [1,2,3,4,5]
        The following example uses fold to calculate the final direction.

    data Direction = North | East | South | West;
    data Turn = Left | Right;
    Direction doTurn(Turn turn, Direction current) {
        case turn of {
            Left -> case current of {
                North -> new = West;
                | West -> new = South;
                | South -> new = East;
                | East -> new = North;
            }
            | Right -> case current of {
                North -> new = East;
                | West -> new = North;
                | South -> new = West;
                | East -> new = South;
            }
        }
        return new;
    }

    Void main() {
        turns = [Left,Left,Left,Right,Right,Left,Right,Left,Left];
        original = West;
        final = fold(doTurn,turns,original);
        // final = North
    }

AUTHORS

       Kaya  standard  library  by  Edwin  Brady,  Chris  Morris  and  others  (kaya@kayalang.org).  For further
       information see http://kayalang.org/

LICENSE

       The Kaya standard library is free software; you can redistribute it and/or modify it under the  terms  of
       the  GNU  Lesser  General  Public  License  (version  2.1  or any later version) as published by the Free
       Software Foundation.

RELATED

       Array.map (3kaya)

Kaya                                                July 2013                                  Array.fold(3kaya)