R/string.r

In crayon: Colored Terminal Output

#' Convert to character
#'
#' This function just calls [as.character()], but it is
#' easier to type and read.
#'
#' @param x Object to be coerced.
#' @param ... Further arguments to pass to `as.character()`.
#' @return Character value.
#'
#' @export

chr <- function(x, ...) as.character(x, ...)

#' Concatenate character vectors
#'
#' The length of the two arguments must match, or
#' one of them must be of length one. If the length of
#' one argument is one, then the output's length will
#' match the length of the other argument. See examples
#' below.
#'
#' @param lhs Left hand side, character vector.
#' @param rhs Right hand side, character vector.
#' @return Concatenated vectors.
#'
#' @name concat
#' @export
#'
#' @examples
#' "foo" %+% "bar"
#'
#' letters[1:10] %+% chr(1:10)
#'
#' letters[1:10] %+% "-" %+% chr(1:10)
#'
#' ## This is empty (unlike for parse)
#' character() %+% "*"

`%+%` <- function(lhs, rhs) {

  stopifnot(is.character(lhs), is.character(rhs))
  stopifnot(length(lhs) == length(rhs) || length(lhs) == 1 || length(rhs) == 1)

  if (length(lhs) == 0 && length(rhs) == 0) {
    paste0(lhs, rhs)

  } else if (length(lhs) == 0) {
    lhs

  } else if (length(rhs) == 0) {
    rhs

  } else {
    paste0(lhs, rhs)
  }
}

#' @export
as.character.crayon <- function(x, ...) {
  start(x)
}

#' @export
`-.crayon` <- function(e1, e2) {
  if (!missing(e2)) {
    base::`-`(e1, e2)
  }
  my_styles <- attr(e1, "_styles")
  if (has_color()) {
    for (i in seq_along(my_styles)) {
      my_styles[[i]]$open <- my_styles[[i]]$close
    }
  }
  attr(e1, "_styles") <- my_styles
  e1
}