ios - Accessing previous values in a ReactiveCocoa -flattenMap:/-then: chain -

let's have chain of reactivecocoa signals using -flattenmap: , -then:, so:

__weak typeof(self) weakself = self  [[[self foosignal] flattenmap:^racstream *(foo *foo) {     return [weakself barsignal]; }] then:^racsignal *{     // create signal using foo }]; 

in case, barsignal dependent on foosignal completing (next-ing, strictly speaking, foosignal once) without error, , next value barsignal nonsensical (+combinelatest: doesn't apply). if sending next, they're dependent operations, not parallel ones.

obviously, can use __block variable access foo, feels stylistically incorrect , hard follow (not strict chain downwards).

i can write custom operator achieve this, that's more code __block variable , difficult make generic, think.

is there clean way access foo?

i drop second -flattenmap: , instead add -then: end of barsignal. foo variable in scope there, , wait until barsignal complete before being subscribed to.

__weak typeof(self) weakself = self  [[self foosignal] flattenmap:^racstream *(foo *foo) {     return [[weakself barsignal] then:^racsignal * {         // create signal using foo         return [racsignal createsignal ...     }]; }];