relax non-strict case a bit

R/let.R

@@ -55,15 +55,19 @@ prepareAlias <- function(alias, strict) {
   nulls <- vapply(names(alias), is.null, logical(1)) |
     vapply(alias, is.null, logical(1))
   alias <- alias[!nulls]
-  # confirm alias is an invertable mapping strings to strings
   if (length(unique(names(alias))) != length(names(alias))) {
     stop('wrapr::prepareAlias alias keys must be unique')
   }
-  if (length(unique(as.character(alias))) != length(alias)) {
-    stop('wrapr::prepareAlias alias values must be unique')
+  if(strict) {
+    # confirm alias is an invertable mapping strings to strings
+    if (length(unique(as.character(alias))) != length(alias)) {
+      stop('wrapr::prepareAlias alias values must be unique')
+    }
   }
-  if ('.' %in% c(names(alias),as.character(alias))) {
-    stop("wrapr::prepareAlias can not map to/from '.'")
+  if(strict) {
+    if ('.' %in% c(names(alias),as.character(alias))) {
+      stop("wrapr::prepareAlias can not map to/from '.'")
+    }
   }
   for (ni in names(alias)) {
     if (is.null(ni)) {
@@ -291,7 +295,7 @@ letprep_lang <- function(alias, lexpr) {
 #' @param expr block to prepare for execution.
 #' @param ... force later arguments to be bound by name.
 #' @param subsMethod character substitution method, one of  c('langsubs', 'stringsubs', 'subsubs').
-#' @param strict logical if TRUE names must be valid un-quoted names.
+#' @param strict logical if TRUE names and values must be valid un-quoted names, not dot, and unique values.
 #' @param eval logical if TRUE execute the re-mapped expression (else return it).
 #' @param debugPrint logical if TRUE print debugging information when in stringsubs mode.
 #' @return result of expr executed in calling environment (or expression if eval==FALSE).