fix to error messages and docs for grid::dataViewport(). Thanks to Avinab Neogy

git-svn-id: https://svn.r-project.org/R/trunk@87840 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: murrell

src/library/grid/R/viewport.R

@@ -454,12 +454,12 @@ dataViewport <- function(xData = NULL, yData = NULL,
     extension <- rep(extension, length.out = 2)
     if (is.null(xscale)) {
         if (is.null(xData))
-            stop("must specify at least one of 'x' or 'xscale'")
+            stop("must specify at least one of 'xData' or 'xscale'")
         xscale <- extendrange(xData, f = extension[1L])
     }
     if (is.null(yscale)) {
         if (is.null(yData))
-            stop("must specify at least one of 'y' or 'yscale'")
+            stop("must specify at least one of 'yData' or 'yscale'")
         yscale <- extendrange(yData, f = extension[2L])
     }
     viewport(xscale = xscale, yscale = yscale, ...)

src/library/grid/man/dataViewport.Rd

@@ -27,8 +27,8 @@ dataViewport(xData = NULL, yData = NULL, xscale = NULL,
     the \code{viewport()} function. }
 }
 \details{
-  If \code{xscale} is not specified then the values in \code{x} are
-  used to generate an x-scale based on the range of \code{x}, extended
+  If \code{xscale} is not specified then the values in \code{xData} are
+  used to generate an x-scale based on the range of \code{xData}, extended
   by the proportion specified in \code{extension}.  Similarly for the
   y-scale.
 }