collections with love

//Smalltalk's "collect", haskell's "map"
- (NSArray *) arrayByEvaluatingBlock:(id(^)(id object))block {
    NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:[self count]];
    for (id object in self) {
        [array addObject:block(object)];
    }
    return [array copy];
}

//Smalltalk's and haskell's "filter"
- (NSArray *)arrayByFilteringWithBlock:(BOOL(^)(id object))block {
    NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:[self count]];
    for (id object in self) {
        if (block(object)) {
            [array addObject:object];
        }
    }
    return [array copy];
}

//Smalltalk's "inject into", haskell "foldl"
- (id)foldingWithBlock:(id(^)(id a, id b))block initialObject:(id)initalObject {
    for (id object in self) {
        initalObject = block(initalObject, object);
    }
    return initalObject;
}