Add a default marshal() method [#7]

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: marshal
-Version: 0.0.1-9002
+Version: 0.0.1-9003
 Title: Framework to Marshal Objects to be Used in Another R Process
 Depends:
     R (>= 3.2.0)

NAMESPACE

@@ -16,6 +16,7 @@ S3method(marshal,XMLAbstractDocument)
 S3method(marshal,XMLAbstractNode)
 S3method(marshal,connection)
 S3method(marshal,data.table)
+S3method(marshal,default)
 S3method(marshal,jclassName)
 S3method(marshal,jobjRef)
 S3method(marshal,keras.engine.base_layer.Layer)

R/marshal.R

@@ -13,6 +13,7 @@
 #' @export
 marshal <- function(...) { UseMethod("marshal") }
 
+
 #' @return
 #' `unmarshal()` returns an unmarshalled version of the original object.
 #'

R/marshal.default.R

@@ -0,0 +1,40 @@
+#' Marshalling of an R objects
+#'
+#' @param x
+#' An R object.
+#'
+#' @param \dots Not used.
+#'
+#' @return
+#' A `marshalled` object as described in [marshal()].
+#'
+#' @details
+#' This is the default, fallback method for marshalling of an
+#' \R object.  It assumes that the object do not need specific
+#' marshalling, but can be serialized as-is.  All this default
+#' method does is wrapping the original object up in a 
+#' `marshalled` object, so that the original object can be
+#' recovered via `unmarshalled()`.
+#'
+#' @example incl/marshal.default.R
+#'
+#' @rdname marshal.default
+#' @aliases marshal.default
+#' @export
+marshal.default <- function(x, ...) {
+  res <- list(
+    marshalled = x
+  )
+  class(res) <- marshal_class(x)
+
+  res[["unmarshal"]] <- unmarshal_default
+
+  res
+}
+
+
+unmarshal_default <- function(x, ...) {
+  res <- x[["marshalled"]]
+  stopifnot(all.equal(class(res), marshal_unclass(x), check.attributes = FALSE))
+  res
+}

incl/marshal.default.R

@@ -0,0 +1,6 @@
+x <- data.frame(a = 1:3, b = letters[1:3])
+x_ <- marshal(x)
+x2 <- unmarshal(x_)
+stopifnot(identical(x2, x))
+
+

tests/marshal.default.R

@@ -0,0 +1,15 @@
+library(marshal)
+
+objects <- list(
+  1:3,
+  rnorm(3),
+  as.list(1:3),
+  data.frame(a = 1:3, b = letters[1:3])
+)
+
+for (x in objects) {
+  x_ <- marshal(x)
+  x2 <- unmarshal(x_)
+  stopifnot(identical(x2, x))
+}
+