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Array.fold(3kaya) | Kaya module reference | Array.fold(3kaya) |
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));
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)August 2014 | Kaya |