allow 'NULL' for entity arguments of avworkflow_run()

- #65

R/avworkflow.R

@@ -365,10 +365,12 @@ avworkflow_localize <-
 #' @param config a `avworkflow_configuration` object of the workflow that will
 #'     be run.
 #'
-#' @param entityName character(1) name of the set of samples to be used when
-#'     running the workflow.
+#' @param entityName character(1) or NULL name of the set of samples
+#'     to be used when running the workflow. NULL indicates that no
+#'     sample set will be used.
 #'
-#' @param entityType character(1) type of root entity used for the workflow.
+#' @param entityType character(1) or NULL type of root entity used for
+#'     the workflow. NULL means that no root entity will be used.
 #'
 #' @param deleteIntermediateOutputFiles logical(1) whether or not to delete
 #'     intermediate output files when the workflow completes.
@@ -401,8 +403,8 @@ avworkflow_run <-
 {
     stopifnot(
         inherits(config, "avworkflow_configuration"),
-        .is_scalar_character(entityName),
-        .is_scalar_character(entityType),
+        .is_scalar_character_or_NULL(entityName),
+        .is_scalar_character_or_NULL(entityType),
         .is_scalar_logical(deleteIntermediateOutputFiles),
         .is_scalar_logical(useCallCache),
         .is_scalar_logical(useReferenceDisks),

R/utilities.R

@@ -9,6 +9,9 @@
 .is_scalar_character <- function(x, na.ok = FALSE, zchar = FALSE)
     length(x) == 1L && .is_character(x, na.ok, zchar)
 
+.is_scalar_character_or_NULL <- function(x, na.ok = FALSE, zchar = FALSE)
+    .is_scalar_character(x, na.ok, zchar) || is.null(x)
+
 .is_character_0_or_1 <-
     function(x, na.ok = FALSE, zchar = FALSE)
 {