diff --git a/pkgs/development/r-modules/generate-r-packages.R b/pkgs/development/r-modules/generate-r-packages.R
index af2678b03105..fb15ec40ad22 100755
--- a/pkgs/development/r-modules/generate-r-packages.R
+++ b/pkgs/development/r-modules/generate-r-packages.R
@@ -1,8 +1,17 @@
 #!/usr/bin/env Rscript
+
+# This script can be used to generate the .json file for a given R package set
+# that is part of the `rPackages` tree
+#
+# See R section of the nixpkgs manual for an example of how to use this script
+
 library(data.table)
 library(parallel)
 library(BiocManager)
-cl <- makeCluster(10)
+library(jsonlite)
+
+# always order strings according to POSIX ordering
+locale <- Sys.setlocale(locale = "C")
 
 biocVersion <- BiocManager:::.version_map()
 biocVersion <- biocVersion[biocVersion$R == getRversion()[, 1:2],c("Bioc", "BiocStatus")]
@@ -20,21 +29,25 @@ mirrorUrls <- list( bioc=paste0("http://bioconductor.org/packages/", biocVersion
 
 mirrorType <- commandArgs(trailingOnly=TRUE)[1]
 stopifnot(mirrorType %in% names(mirrorUrls))
-packagesFile <- paste(mirrorType, 'packages.nix', sep='-')
-readFormatted <- as.data.table(read.table(skip=8, sep='"', text=head(readLines(packagesFile), -1)))
+
+packagesFile <- paste(mirrorType, 'packages.json', sep='-')
+prevPkgs <- fromJSON(packagesFile)$packages
 
 write(paste("downloading package lists"), stderr())
-knownPackages <- lapply(mirrorUrls, function(url) as.data.table(available.packages(url, filters=c("R_version", "OS_type", "duplicates")), method="libcurl"))
-pkgs <- knownPackages[mirrorType][[1]]
-setkey(pkgs, Package)
-knownPackages <- c(unique(do.call("rbind", knownPackages)$Package))
-knownPackages <- sapply(knownPackages, gsub, pattern=".", replacement="_", fixed=TRUE)
+pkgTables <- lapply(mirrorUrls, function(url) as.data.table(available.packages(url, filters=c("R_version", "OS_type", "duplicates")), method="libcurl"))
+knownPackageNames <- c(unique(do.call("rbind", pkgTables)$Package))
 
+pkgTable <- pkgTables[mirrorType][[1]]
 mirrorUrl <- mirrorUrls[mirrorType][[1]]
+
+escapeName <- function(name) {
+    gsub(".", "_", switch(name, "import" = "r_import", "assert" = "r_assert", name), fixed=TRUE)
+}
+
 nixPrefetch <- function(name, version) {
-  prevV <- readFormatted$V2 == name & readFormatted$V4 == version
-  if (sum(prevV) == 1)
-    as.character(readFormatted$V6[ prevV ])
+  prevPkg <- prevPkgs[[escapeName(name)]]
+  if (!is.null(prevPkg) && prevPkg$version == version)
+    prevPkg$sha256
 
   else {
     # avoid nix-prefetch-url because it often fails to fetch/hash large files
@@ -53,12 +66,7 @@ nixPrefetch <- function(name, version) {
 
 }
 
-escapeName <- function(name) {
-    switch(name, "import" = "r_import", "assert" = "r_assert", name)
-}
-
 formatPackage <- function(name, version, sha256, depends, imports, linkingTo) {
-    attr <- gsub(".", "_", escapeName(name), fixed=TRUE)
     options(warn=5)
     depends <- paste( if (is.na(depends)) "" else gsub("[ \t\n]+", "", depends)
                     , if (is.na(imports)) "" else gsub("[ \t\n]+", "", imports)
@@ -67,48 +75,44 @@ formatPackage <- function(name, version, sha256, depends, imports, linkingTo) {
                     )
     depends <- unlist(strsplit(depends, split=",", fixed=TRUE))
     depends <- lapply(depends, gsub, pattern="([^ \t\n(]+).*", replacement="\\1")
-    depends <- lapply(depends, gsub, pattern=".", replacement="_", fixed=TRUE)
-    depends <- depends[depends %in% knownPackages]
+    depends <- depends[depends %in% knownPackageNames]
     depends <- lapply(depends, escapeName)
     depends <- paste(depends)
-    depends <- paste(sort(unique(depends)), collapse=" ")
-    paste0("  ", attr, " = derive2 { name=\"", name, "\"; version=\"", version, "\"; sha256=\"", sha256, "\"; depends=[", depends, "]; };")
+    depends <- sort(unique(depends))
+    list(name=unbox(name), version=unbox(version), sha256=unbox(sha256), depends=depends)
 }
 
-clusterExport(cl, c("nixPrefetch","readFormatted", "mirrorUrl", "mirrorType", "knownPackages"))
-
-pkgs <- pkgs[order(Package)]
+cl <- makeCluster(10)
+clusterExport(cl, c("escapeName", "nixPrefetch", "prevPkgs", "mirrorUrl", "mirrorType", "knownPackageNames"))
 
 write(paste("updating", mirrorType, "packages"), stderr())
-pkgs$sha256 <- parApply(cl, pkgs, 1, function(p) nixPrefetch(p[1], p[2]))
-nix <- apply(pkgs, 1, function(p) formatPackage(p[1], p[2], p[18], p[4], p[5], p[6]))
-write("done", stderr())
-
-# Mark deleted packages as broken
-setkey(readFormatted, V2)
-markBroken <- function(name) {
-  str <- paste0(readFormatted[name], collapse='"')
-  if(sum(grep("broken = true;", str)))
-    return(str)
-  write(paste("marked", name, "as broken"), stderr())
-  gsub("};$", "broken = true; };", str)
-}
-broken <- lapply(setdiff(readFormatted[[2]], pkgs[[1]]), markBroken)
-
-cat("# This file is generated from generate-r-packages.R. DO NOT EDIT.\n")
-cat("# Execute the following command to update the file.\n")
-cat("#\n")
-cat(paste("# Rscript generate-r-packages.R", mirrorType, ">new && mv new", packagesFile))
-cat("\n\n")
-cat("{ self, derive }:\n")
-cat("let derive2 = derive ")
-if (mirrorType == "cran") { cat("{  }")
-} else if (mirrorType == "irkernel") { cat("{}")
-} else { cat("{ biocVersion = \"", biocVersion, "\"; }", sep="") }
-cat(";\n")
-cat("in with self; {\n")
-cat(paste(nix, collapse="\n"), "\n", sep="")
-cat(paste(broken, collapse="\n"), "\n", sep="")
-cat("}\n")
+pkgTable$sha256 <- parApply(cl, pkgTable, 1, function(p) nixPrefetch(p[1], p[2]))
 
 stopCluster(cl)
+
+pkgs <- lapply(1:nrow(pkgTable), function(i) with(pkgTable[i,], formatPackage(Package, Version, sha256, Depends, Imports, LinkingTo)))
+names(pkgs) <- lapply(pkgs, function(p) escapeName(p$name))
+
+# Mark deleted packages as broken
+brokenPkgs <- lapply(prevPkgs[setdiff(names(prevPkgs), names(pkgs))], function(p)
+  list(name=unbox(p$name),
+       version=unbox(p$version),
+       sha256=unbox(p$sha256),
+       depends=p$depends,
+       broken=unbox(T)))
+
+# sort packages by their non-escaped names
+pkgs <- pkgs[order(sapply(pkgs, function(p) p$name))]
+brokenPkgs<- brokenPkgs[order(sapply(brokenPkgs, function(p) p$name))]
+
+# empty named list
+extraArgs = setNames(list(), character(0))
+
+if (mirrorType != "cran") {
+  extraArgs=list(biocVersion=unbox(paste(biocVersion)))
+}
+
+cat(toJSON(list(extraArgs=extraArgs, packages=c(pkgs, brokenPkgs)), pretty=TRUE))
+cat("\n")
+write("done", stderr())
+
diff --git a/pkgs/development/r-modules/generate-shell.nix b/pkgs/development/r-modules/generate-shell.nix
index 1c96cf05cb54..1588aa9b76d7 100644
--- a/pkgs/development/r-modules/generate-shell.nix
+++ b/pkgs/development/r-modules/generate-shell.nix
@@ -17,6 +17,7 @@ stdenv.mkDerivation {
         data_table
         parallel
         BiocManager
+        jsonlite
       ];
     })
   ];