Patch the infinite recursion of asJSON on subclasses of vctrs_vctr instances…

DESCRIPTION

@@ -21,6 +21,7 @@ Description: A reasonably fast JSON parser and generator, optimized for statisti
     functions to stream, validate, and prettify JSON data. The unit tests included 
     with the package verify that all edge cases are encoded and decoded consistently 
     for use with dynamic data in systems and applications.
+Imports:
 Suggests:
     httr,
     vctrs,
@@ -29,6 +30,6 @@ Suggests:
     rmarkdown,
     R.rsp,
     sf
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.1
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)

NAMESPACE

@@ -3,6 +3,7 @@
 S3method("[",json)
 S3method(print,json)
 S3method(print,scalar)
+S3method(vec_proxy_json,vctrs_vctr)
 export(as_gzjson_b64)
 export(as_gzjson_raw)
 export(base64_dec)
@@ -25,6 +26,7 @@ export(toJSON)
 export(unbox)
 export(unserializeJSON)
 export(validate)
+export(vec_proxy_json)
 export(write_json)
 import(methods)
 useDynLib(jsonlite,C_collapse_array)

R/asJSON.vctrs.R

@@ -1,5 +1,31 @@
 setMethod("asJSON", "vctrs_vctr", function(x, ...) {
-  # dispatch based on the underlying type
-  class(x) <- setdiff(class(x), 'vctrs_vctr')
-  asJSON(x, ...)
+  tryCatch(
+    {
+      asJSON(vec_proxy_json(x), ...)
+    },
+    error = function(cond) {
+      selectMethod(asJSON, "ANY")(x)
+    }
+  )
 })
+
+#' JSON conversion proxy
+#' 
+#' vec_proxy_json method returns proxy objects, i.e. an atomic vector or a list of atomic vectors,
+#' able to be converted to JSON using the jsonlite package. This is a generic S3 method, that has
+#' to be implemented for subclasses requesting particualar JSON conversion. A default implementation
+#' is provided for `vctrs_vctr` class.
+#' 
+#' @param x object instance of class `vctrs_vctr` to be converted to JSON
+#' 
+#' @return an atomic vector or a list of atomic vectors.
+#' @export
+vec_proxy_json <- function(x) {
+  UseMethod("vec_proxy_json", x)
+}
+
+#' @export
+vec_proxy_json.vctrs_vctr <- function(x) {
+  class(x) <- setdiff(class(x), "vctrs_vctr")
+  x
+}

jsonlite.Rproj

@@ -17,3 +17,4 @@ StripTrailingWhitespace: Yes
 
 BuildType: Package
 PackageInstallArgs: --no-multiarch --with-keep.source --install-tests
+PackageRoxygenize: rd,collate,namespace