How to use %>>% / perform side effects

[yogat3ch]

Hi mirai devs
I'm unable to make sense of how to feasibly put mirai to use from the examples provided in the documentation. Below is a simple use case to demonstrate.
I would expect env$test to evaluate to TRUE, but it's just NULL

library(mirai)
env <- new.env()
mirai::.(
  mirai::mirai({
    Sys.sleep(5)
    TRUE
  }) %>>%
  assign(x = "test", envir = env)
 )
Sys.sleep(6)
env$test

I've pored over the documentation for far too long now and just can't make sense of how to use mirai in production, any help?

[shikokuchuo]

The deferred execution pipe %>>% requires the mirai to be assigned to a variable outside of the .() scope and a check for resolution by unresolved() or directly accessing the active binding b$data.

So for you example above:

library(mirai)
env <- new.env()
m <- mirai({
  Sys.sleep(5)
  TRUE
})
b <- .(m %>>% assign(x = "test", envir = env))
Sys.sleep(6)
if (!unresolved(b)) env$test

However if you only care about the side effect (performing the assignment to the environment) rather than using the return value, then using mirai promises and a different pipe may be a better fit. For example:

library(mirai)
library(promises)
library(mirai.promises)
env <- new.env()
mirai({
  Sys.sleep(5)
  TRUE
}) %...>% assign(x = "test", envir = env)
Sys.sleep(6)
env$test

[yogat3ch]

The second example with mirai.promises is the ticket, that's exactly what I'm looking for. It seems like mirai.promises is definitely what I'm interested in, thank you @shikokuchuo !