Add coro into the future example api

DESCRIPTION

@@ -47,6 +47,7 @@ Suggests:
     yaml,
     feather,
     future,
+    coro,
     rstudioapi,
     mockery (>= 0.4.2)
 RoxygenNote: 7.1.1

inst/plumber/14-future/plumber.R

@@ -1,10 +1,10 @@
 
 library(promises)
-library(future)
-
+library(coro)
 future::plan("multisession") # a worker for each core
 # future::plan(future::multisession(workers = 2)) # only two workers
 
+
 # Quick manual test:
 # Within 10 seconds...
 # 1. Visit /future
@@ -24,8 +24,8 @@ function() {
 #' @get /future
 function() {
 
-  future({
-    # perform large computations
+  future_promise({
+    # perform long running computations
     Sys.sleep(10)
 
     # print route, time, and worker pid
@@ -34,6 +34,43 @@ function() {
 }
 
 
+# A function that will return a promise object
+calc_using_promise <- function() {
+  # Executes using `future`
+  future_promise({
+    # perform long computations
+    Sys.sleep(1)
+
+    # return which process id was used
+    Sys.getpid()
+  }) %...>% {
+    exec_pid <- .
+    main_pid <- Sys.getpid()
+    # print route, time, and worker pid
+    paste0("/coro; ", Sys.time(), "; exec pid:", exec_pid, "; main pid:", main_pid)
+
+    list(exec_pid = exec_pid, main_pid = main_pid)
+  }
+}
+
+#' For more info about `coro`, visit https://coro.r-lib.org
+#' @contentType text
+#' @serializer json list(auto_unbox = TRUE)
+#' @get /coro
+async(function() {
+
+  # (a)wait for the promised value and use as a regular value
+  # No neeed for a followup promise when using `await(p)`
+  pids <- await(calc_using_promise())
+
+  # Write code with the finalized async value as if it was synchronously found
+  pids$exec_is_even <- pids$exec_pid %% 2 == 0
+
+  # return info
+  pids
+})
+
+
 # -----------------------------------
 
 
@@ -43,7 +80,7 @@ function() {
 #' @param a number
 #' @param b number
 function(a = NA, b = NA) {
-  future({
+  future_promise({
     a <- as.numeric(a)
     b <- as.numeric(b)
     if (is.na(a)) stop("a is missing")
@@ -59,23 +96,24 @@ function(a = NA, b = NA) {
 #' @param a number
 #' @param b number
 function(a = NA, b = NA) {
-  future({
+  future_promise({
     a <- as.numeric(a)
     b <- as.numeric(b)
     if (is.na(a)) stop("a is missing")
     if (is.na(b)) stop("b is missing")
     if (b == 0) stop("Cannot divide by 0")
 
     a / b
-  }) %>%
+  }) %...!%
     # Handle `future` errors
-    promises::catch(function(error) {
+    {
+      error <- .
       # handle error here!
       if (error$message == "b is missing") {
         return(Inf)
       }
 
       # rethrow original error
       stop(error)
-    })
+    }
 }