Usage
## S3 method for class 'default}(hookName, ..., removeCalledHooks=FALSE)':
callHooksundefined
- hookName
{A character
string of the hook name.}
- ...
{Argument passed to each hook function.}
- removeCalledHooks
{If TRUE
, called hook functions are removed,
otherwise not.}
Returns (invisibly) whatever callHooks.list
() returns.
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Example 1
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# First, clean up if called more than once
setHook("myFunction.onEnter", NULL, action="replace")
setHook("myFunction.onExit", NULL, action="replace")
runConference <- function(...) {
callHooks("myFunction.onEnter")
cat("Speaker A: Hello there...
")
callHooks("myFunction.onExit")
}
setHook("myFunction.onEnter", function(...) {
cat("Chair: Welcome to our conference.
")
})
setHook("myFunction.onEnter", function(...) {
cat("Chair: Please welcome Speaker A!
")
})
setHook("myFunction.onExit", function(...) {
cat("Chair: Please thanks Speaker A!
")
})
runConference()
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Example 2
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
setHook("randomNumber", NULL, action="replace")
setHook("randomNumber", rnorm) # By function
setHook("randomNumber", "rexp") # By name
setHook("randomNumber", "runiff") # Non-existing name
setHook("randomNumber", .GlobalEnv) # Not a function
res <- callHooks("randomNumber", n=1)
str(res)
cat("Number of hooks: ", length(res), "
");
isErroneous <- unlist(lapply(res, FUN=function(x) !is.null(x$exception)));
cat("Erroneous hooks: ", sum(isErroneous), "
");
[object Object]
Internally, after retriving hook functions, callHooks.list
() is
called.
See UserHooks how to set hooks.
programming