For

For

The For class in cyclops-react provides For comprehensions for Publishers, Values and access to the lower level Do builder for other types (iterable, reader, future, optional, Stream anyM).

## Examples

We can perform a For comprehension with a Filter over a Flux type (from Pivotal's Reactor project) and a cyclops-react ReactiveSeq. This will visit every element of both Streams. In this example we will filter out any combination where the total is less than 10.

import static com.aol.cyclops.control.For.Publishers.each2;

ListX<Tuple2<Integer,Integer>>  list;


list = each2(Flux.range(1,10), 
             i-> ReactiveSeq.iterate(i,a->a+1)
                            .limit(10),
             (a,b)->a+b<10,
             Tuple::tuple)
       .toListX();

Ultimately this is syntax sugar for the code below, where we perform a nested map operation inside a flatMap operation.

ListX<Tuple2<Integer,Integer>>  list2;  
list2 = Flux.range(1,10)
            .flatMap(i-> ReactiveSeq.iterate(i,a->a+1)
                                    .limit(10)
                                    .filter(a->i+a<10)
                                    .map(a->Tuple.tuple(i,a)))
             .toList()
             .block();
                                    
assertThat(list,equalTo(list2));

Example : Flux, ReactiveSeq, Maybe and Mono via For.Publishers

With For.Publishers we can execute For comprehensions, that perform nested loops over any Publisher type.

import org.jooq.lambda.tuple.Tuple;
import org.jooq.lambda.tuple.Tuple4;
import static com.aol.cyclops.control.For.Publishers.each4;

ListX<Tuple4<Integer,Integer,Integer,Integer>>  list;

list = each4(Flux.range(1,10), 
             a-> ReactiveSeq.iterate(a,i->i+1).limit(10),
             (a,b) -> Maybe.<Integer>of(a+b),
             (a,b,c) -> Mono.<Integer>just(a+b+c),
             Tuple::tuple)
            .toListX();