src/library/base/R/structure.R

#  File src/library/base/R/structure.R
#  Part of the R package, https://www.R-project.org
#
#  Copyright (C) 1995-2018 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.
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## This remaps special names as they are used by deparsing, but why are they?
##
structure <- function (.Data, ...)
{
    if(is.null(.Data))
        warning("Calling 'structure(NULL, *)' is deprecated, as NULL cannot have attributes.\n  Consider 'structure(list(), *)' instead.")
        ## to become: stop("attempt to set an attribute on NULL")
    attrib <- list(...)
    if(length(attrib)) {
        specials <- c(".Dim", ".Dimnames", ".Names", ".Tsp", ".Label")
        replace <- c("dim", "dimnames", "names", "tsp", "levels")
	m <- match(names(attrib), specials)
	ok <- !is.na(m)
	names(attrib)[ok] <- replace[m[ok]]
        ## prior to 2.5.0 factors would deparse to double codes
	if("factor" %in% attrib[["class", exact = TRUE]]
           && typeof(.Data) == "double")
            storage.mode(.Data) <- "integer"
        attributes(.Data) <- c(attributes(.Data), attrib)
        .Data
    }
    else .Data
}