pkgmaker 0.16

Postponing Actions

Usage

postponeAction(expr, key = digest(tempfile()), group = NULL, envir = topns(strict = FALSE), 
  verbose = getOption("verbose"))

runPostponedAction(group = NULL, verbose = getOption("verbose"))

Arguments

expr
expression that define the action to postpone. Currently only functions are supported.
key
identifier for this specific action. It should be unique across the postponed actions from the same group.
group
optional parent action group. This enables to define meaningful sets of actions that can be run all at once.
envir
environment in which the action should be executed. Currently not used.
verbose
logical that toggles verbose messages.

Description

This function implement a mechanism to postpone actions, which can be executed at a later stage. This is useful when developing packages, where actions that need to be run in the link{.onLoad} function but can be defined close to their context.

Examples

opt <- options(verbose=2)

# define actions
postponeAction(function(){print(10)}, "print")


# Postponing action 'print'
postponeAction(function(){print(1:10)}, "more")


# Postponing action 'more'
postponeAction()



[1] "print" "more" 

# execute actions
runPostponedAction()


# Executing postponed action(s) in package 'R_GlobalEnv' ... 

** Action 'print' [R_GlobalEnv]

[1] 10


** Action 'more' [R_GlobalEnv]

 [1]  1  2  3  4  5  6  7  8  9 10


OK [2]
runPostponedAction()


# Executing postponed action(s) in package 'R_GlobalEnv' ... 
OK [0]
# restore options
options(opt)