R/zzz.R

In christyray/crthemes: A Standardized ggplot2 Theme for Visualizations

# Utility and background functions

# Defaults for NULL values; use a unless a is NULL, then use b
# Used if an argument is optional and there is a means to calculate the default
`%||%` <- function(a, b) if (is.null(a)) b else a

# Opposite of the above function; use a if it is NULL; otherwise, evaluate b
`%keepnull%` <- function(a, b) if (is.null(a)) a else b

# Returns non-null arguments as symbols that can be evaluated
non_null <- function(...) {
  pf <- parent.frame()
  args <- rlang::ensyms(...)

  notnull <- sapply(args, function(arg) { !is.null(eval(arg, envir = pf)) })
  args[notnull]
}