Improve description of nan=

Author: MichaelChirico

man/nafill.Rd

@@ -14,11 +14,11 @@ nafill(x, type=c("const","locf","nocb"), fill=NA, nan=NA)
 setnafill(x, type=c("const","locf","nocb"), fill=NA, nan=NA, cols=seq_along(x))
 }
 \arguments{
-  \item{x}{ vector, list, data.frame or data.table of numeric columns. }
-  \item{type}{ character, one of \emph{"const"}, \emph{"locf"} or \emph{"nocb"}. Defaults to \code{"const"}. }
-  \item{fill}{ numeric or integer, value to be used to fill. }
-  \item{nan}{ (numeric \code{x} only) Either \code{NaN} or \code{NA}; if the former, \code{NaN} is treated as distinct from \code{NA}, otherwise, they are treated the same during replacement? }
-  \item{cols}{ numeric or character vector specifying columns to be updated. }
+  \item{x}{ Vector, list, data.frame or data.table of numeric columns. }
+  \item{type}{ Character, one of \emph{"const"}, \emph{"locf"} or \emph{"nocb"}. Defaults to \code{"const"}. }
+  \item{fill}{ Double or integer, value to be used to fill. }
+  \item{nan}{ Either \code{NaN} or \code{NA}; if the former, \code{NaN} is treated as distinct from \code{NA}, otherwise, they are treated the same during replacement. See Examples. }
+  \item{cols}{ Numeric or character vector specifying columns to be updated. }
 }
 \details{
   Only \emph{double} and \emph{integer} data types are currently supported.
@@ -33,6 +33,10 @@ x = 1:10
 x[c(1:2, 5:6, 9:10)] = NA
 nafill(x, "locf")
 
+x = c(1, NA, NaN, 3, NaN, NA, 4)
+nafill(x, "locf")
+nafill(x, "locf", nan=NaN)
+
 dt = data.table(v1=x, v2=shift(x)/2, v3=shift(x, -1L)/2)
 nafill(dt, "nocb")