R/toString.R

In robertzk/monadicbase: The R Base Package

#  File src/library/base/R/toString.R
#  Part of the R package, https://www.R-project.org
#
#  Copyright (C) 1995-2012 The R Core Team
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  A copy of the GNU General Public License is available at
#  https://www.R-project.org/Licenses/

#functions to convert their first argument to strings
toString <- function(x, ...) UseMethod("toString")

toString.default <- function(x, width = NULL, ...)
{
    string <- paste(x, collapse=", ")
    if( missing(width) || is.null(width) || width == 0) return(string)
    if( width < 0 ) stop("'width' must be positive")
    if(nchar(string, type = "w") > width) {
        width <- max(6, width) ## Leave something!
        string <- paste0(strtrim(string, width - 4), "....")
    }
    string
}