revdep/checks.noindex/promises/new/promises.Rcheck/promises-Ex.R

In ijlyttle/vembedr: Embed Video in HTML

pkgname <- "promises"
source(file.path(R.home("share"), "R", "examples-header.R"))
options(warn = 1)
library('promises')

base::assign(".oldSearch", base::search(), pos = 'CheckExEnv')
base::assign(".old_wd", base::getwd(), pos = 'CheckExEnv')
cleanEx()
nameEx("future_promise")
### * future_promise

flush(stderr()); flush(stdout())

### Name: future_promise_queue
### Title: 'future' promise
### Aliases: future_promise_queue future_promise

### ** Examples




cleanEx()
nameEx("pipes")
### * pipes

flush(stderr()); flush(stdout())

### Name: pipes
### Title: Promise pipe operators
### Aliases: pipes %...>% %...T>% %...!% %...T!%

### ** Examples

## Not run: 
##D library(future)
##D plan(multisession)
##D 
##D future_promise(cars) %...>%
##D   head(5) %...T>%
##D   print()
##D 
##D # If the read.csv fails, resolve to NULL instead
##D future_promise(read.csv("http://example.com/data.csv")) %...!%
##D   { NULL }
## End(Not run)




cleanEx()
nameEx("promise")
### * promise

flush(stderr()); flush(stdout())

### Name: promise
### Title: Create a new promise object
### Aliases: promise

### ** Examples

# Create a promise that resolves to a random value after 2 secs
p1 <- promise(function(resolve, reject) {
  later::later(~resolve(runif(1)), delay = 2)
})

p1 %...>% print()

# Create a promise that errors immediately
p2 <- promise(~{
  reject("An error has occurred")
})
then(p2,
  onFulfilled = ~message("Success"),
  onRejected = ~message("Failure")
)




cleanEx()
nameEx("promise_all")
### * promise_all

flush(stderr()); flush(stdout())

### Name: promise_all
### Title: Combine multiple promise objects
### Aliases: promise_all promise_race

### ** Examples

p1 <- promise(~later::later(~resolve(1), delay = 1))
p2 <- promise(~later::later(~resolve(2), delay = 2))

# Resolves after 1 second, to the value: 1
promise_race(p1, p2) %...>% {
  cat("promise_race:\n")
  str(.)
}

# Resolves after 2 seconds, to the value: list(1, 2)
promise_all(p1, p2) %...>% {
  cat("promise_all:\n")
  str(.)
}




cleanEx()
nameEx("promise_map")
### * promise_map

flush(stderr()); flush(stdout())

### Name: promise_map
### Title: Promise-aware lapply/map
### Aliases: promise_map

### ** Examples

# Waits x seconds, then returns x*10
wait_this_long <- function(x) {
  promise(~later::later(~{
    resolve(x*10)
  }, delay = x))
}

promise_map(list(A=1, B=2, C=3), wait_this_long) %...>%
  print()




cleanEx()
nameEx("promise_reduce")
### * promise_reduce

flush(stderr()); flush(stdout())

### Name: promise_reduce
### Title: Promise-aware version of Reduce
### Aliases: promise_reduce

### ** Examples

# Returns a promise for the sum of e1 + e2, with a 0.5 sec delay
slowly_add <- function(e1, e2) {
  promise(~later::later(~resolve(e1 + e2), delay = 0.5))
}

# Prints 55 after a little over 5 seconds
promise_reduce(1:10, slowly_add, .init = 0) %...>% print()




cleanEx()
nameEx("promise_resolve")
### * promise_resolve

flush(stderr()); flush(stdout())

### Name: promise_resolve
### Title: Create a resolved or rejected promise
### Aliases: promise_resolve promise_reject

### ** Examples

promise_resolve(mtcars) %...>%
  head() %...>%
  print()

promise_reject("Something went wrong") %...T!%
  { message(conditionMessage(.)) }




### * <FOOTER>
###
cleanEx()
options(digits = 7L)
base::cat("Time elapsed: ", proc.time() - base::get("ptime", pos = 'CheckExEnv'),"\n")
grDevices::dev.off()
###
### Local variables: ***
### mode: outline-minor ***
### outline-regexp: "\\(> \\)?### [*]+" ***
### End: ***
quit('no')