R/utils.R

In certe-medical-epidemiology/certestyle: A Certe R Package for Applying Certe Organisational Style

# ===================================================================== #
#  An R package by Certe:                                               #
#  https://github.com/certe-medical-epidemiology                        #
#                                                                       #
#  Licensed as GPL-v2.0.                                                #
#                                                                       #
#  Developed at non-profit organisation Certe Medical Diagnostics &     #
#  Advice, department of Medical Epidemiology.                          #
#                                                                       #
#  This R package is free software; you can freely use and distribute   #
#  it for both personal and commercial purposes under the terms of the  #
#  GNU General Public License version 2.0 (GNU GPL-2), as published by  #
#  the Free Software Foundation.                                        #
#                                                                       #
#  We created this package for both routine data analysis and academic  #
#  research and it was publicly released in the hope that it will be    #
#  useful, but it comes WITHOUT ANY WARRANTY OR LIABILITY.              #
# ===================================================================== #

#' @importFrom rstudioapi getThemeInfo
is_dark_theme <- function() {
  isTRUE(tryCatch(getThemeInfo()$dark, error = function(e) FALSE))
}

s3_register <- function(generic, class, method = NULL) {
  stopifnot(is.character(generic), length(generic) == 1)
  stopifnot(is.character(class), length(class) == 1)
  pieces <- strsplit(generic, "::")[[1]]
  stopifnot(length(pieces) == 2)
  package <- pieces[[1]]
  generic <- pieces[[2]]
  caller <- parent.frame()
  get_method_env <- function() {
    top <- topenv(caller)
    if (isNamespace(top)) {
      asNamespace(environmentName(top))
    }
    else {
      caller
    }
  }
  get_method <- function(method, env) {
    if (is.null(method)) {
      get(paste0(generic, ".", class), envir = get_method_env())
    }
    else {
      method
    }
  }
  method_fn <- get_method(method)
  stopifnot(is.function(method_fn))
  setHook(packageEvent(package, "onLoad"), function(...) {
    ns <- asNamespace(package)
    method_fn <- get_method(method)
    registerS3method(generic, class, method_fn, envir = ns)
  })
  if (!isNamespaceLoaded(package)) {
    return(invisible())
  }
  envir <- asNamespace(package)
  if (exists(generic, envir)) {
    registerS3method(generic, class, method_fn, envir = envir)
  }
  invisible()
}