change misleading source() to datasource()

R/datasource.R

@@ -0,0 +1,58 @@
+#' @title Get/set the Source of the object.
+#' @description Get/set the optional \code{Source} property as an attribute to an
+#' R object. Do not confuse with the base R \code{source()} function.
+#' @details The \code{Source} is a related resource from which the described resource is
+#' derived. See \href{https://purl.org/dc/elements/1.1/source}{dct:source}. In Datacite,
+#' the source is described by a \code{relatedIdentifierType} with the property
+#' \code{relationType="isDerivedFrom"}.
+#' @param value The \code{Source} as a character string of lengths one.
+#' @inheritParams dublincore
+#' @return The \code{Source} attribute as a character of length 1 is added to \code{x}.
+#' @examples
+#' datasource(iris_dataset) <- "https://doi.org/10.1111/j.1469-1809.1936.tb02137.x"
+#' datasource(iris_dataset)
+#' @family Reference metadata functions
+#' @export
+datasource <- function(x) {
+
+  assertthat::assert_that(is.dataset(x),
+                          msg = "datasource(x) must be a dataset object created with dataset() or as_dataset().")
+  DataBibentry <- dataset_bibentry(x)
+  DataBibentry$source
+
+}
+
+#' @rdname dataset_source
+#' @export
+`datasource<-` <- function(x,  overwrite = TRUE, value) {
+
+  assertthat::assert_that(is.dataset(x),
+                          msg = "datasource(x): x must be a dataset object created with dataset() or as_dataset().")
+
+  DataBibentry <- invisible(dataset_bibentry(x))
+
+  if ( is.null(value) ) {
+    DataBibentry$source <- ":unas"
+    attr(x, "DataBibentry") <- DataBibentry
+    return(invisible(x))
+  }
+
+  if (length(value)>1) {
+    stop("source(x) <- value: value must be of length 1.")
+  }
+
+  is_unas <- DataBibentry$source  ==  ":unas"
+
+  if (is.null(DataBibentry$source)) {
+    DataBibentry$source <- value
+  } else if (is_unas) {
+    DataBibentry$source <- value
+  }else if ( overwrite ) {
+    DataBibentry$source <- value
+  } else {
+    message ("The dataset has already a source: ",    DataBibentry$source )
+  }
+
+  attr(x, "DataBibentry") <- DataBibentry
+  invisible(x)
+}

tests/testthat/test-datasource.R

@@ -0,0 +1,11 @@
+datasource(x=iris_dataset) <- NULL
+
+test_that("datasource() initializes :unas unassigned value", {
+  expect_equal(datasource(iris_dataset), ":unas")
+})
+
+datasource(iris_dataset) <- "https://doi.org/10.1111/j.1469-1809.1936.tb02137.x"
+
+test_that("dataset_source() <- assignment works", {
+  expect_equal(datasource(iris_dataset), "https://doi.org/10.1111/j.1469-1809.1936.tb02137.x")
+})