Add support for specifying indendation

NEWS

@@ -1,5 +1,6 @@
 0.9.14
  - Add support for digits = I(n) to use significant precision.
+ - When 'pretty' in toJSON is numeric, it specifies the number of spaces to indent.
 
 0.9.13
  - Ported some number formatting to C

R/fromJSON.R

@@ -37,7 +37,7 @@
 #' @param auto_unbox automatically \code{\link{unbox}} all atomic vectors of length 1. It is usually safer to avoid this and instead use the \code{\link{unbox}} function to unbox individual elements.
 #' @param digits max number of digits (after the dot) to print for numeric values. See: \code{\link{round}}
 #' @param force unclass/skip objects of classes with no defined JSON mapping
-#' @param pretty adds indentation whitespace to JSON output. See \code{\link{prettify}}
+#' @param pretty adds indentation whitespace to JSON output. Can be TRUE/FALSE or a number specifying the number of spaces to indent. See \code{\link{prettify}}
 #' @param ... arguments passed on to class specific \code{print} methods
 #' @references Jeroen Ooms (2014). The \code{jsonlite} Package: A Practical and Consistent Mapping Between JSON Data and \R{} Objects. \emph{arXiv:1403.2805}. \url{http://arxiv.org/abs/1403.2805}
 #' @examples #stringify some data

R/prettify.R

@@ -6,14 +6,15 @@
 #' @aliases minify prettify
 #' @export prettify minify
 #' @param txt JSON string
+#' @param indent number of spaces to indent
 #' @useDynLib jsonlite R_reformat
 #' @examples myjson <- toJSON(cars)
 #' cat(myjson)
 #' prettify(myjson)
 #' minify(myjson)
-prettify <- function(txt) {
+prettify <- function(txt, indent = 4) {
   txt <- paste(txt, collapse = "\n")
-  reformat(txt, TRUE)
+  reformat(txt, TRUE, indent_string = paste(rep(" ", as.integer(indent)), collapse=""))
 }
 
 #' @rdname prettify
@@ -22,8 +23,8 @@ minify <- function(txt) {
   reformat(txt, FALSE)
 }
 
-reformat <- function(x, pretty){
-  out <- .Call(R_reformat, x, pretty);
+reformat <- function(x, pretty, indent_string = ""){
+  out <- .Call(R_reformat, x, pretty, indent_string = indent_string);
   if(out[[1]] == 0) {
     return(out[[2]])
   } else {

R/toJSON.R

@@ -38,6 +38,8 @@ toJSON <- function(x, dataframe = c("rows", "columns"), matrix = c("rowmajor", "
   #prettify
   if (isTRUE(pretty)) {
     prettify(ans)
+  } else if(is.numeric(pretty)) {
+    prettify(ans, pretty)
   } else {
     class(ans) <- "json"
     return(ans)

man/fromJSON.Rd

@@ -53,7 +53,7 @@ toJSON(x, dataframe = c("rows", "columns"), matrix = c("rowmajor",
 
 \item{digits}{max number of digits (after the dot) to print for numeric values. See: \code{\link{round}}}
 
-\item{pretty}{adds indentation whitespace to JSON output. See \code{\link{prettify}}}
+\item{pretty}{adds indentation whitespace to JSON output. Can be TRUE/FALSE or a number specifying the number of spaces to indent. See \code{\link{prettify}}}
 
 \item{force}{unclass/skip objects of classes with no defined JSON mapping}
 }

man/prettify.Rd

@@ -5,12 +5,14 @@
 \alias{prettify, minify}
 \title{Prettify or minify a JSON string}
 \usage{
-prettify(txt)
+prettify(txt, indent = 4)
 
 minify(txt)
 }
 \arguments{
 \item{txt}{JSON string}
+
+\item{indent}{number of spaces to indent}
 }
 \description{
 Prettify adds indentation to a JSON string; minify removes all indentation/whitespace.

src/prettify.c

@@ -84,7 +84,7 @@ static yajl_callbacks callbacks = {
     reformat_end_array
 };
 
-SEXP R_reformat(SEXP x, SEXP pretty) {
+SEXP R_reformat(SEXP x, SEXP pretty, SEXP indent_string) {
     yajl_status stat;
     yajl_handle hand;
     yajl_gen g;
@@ -93,6 +93,7 @@ SEXP R_reformat(SEXP x, SEXP pretty) {
     /* init generator */
     g = yajl_gen_alloc(NULL);
     yajl_gen_config(g, yajl_gen_beautify, asInteger(pretty));
+    yajl_gen_config(g, yajl_gen_indent_string, translateCharUTF8(asChar(indent_string)));
     yajl_gen_config(g, yajl_gen_validate_utf8, 0);
 
     /* init parser */