paleolimbot commented on code in PR #288: URL: https://github.com/apache/arrow-nanoarrow/pull/288#discussion_r1311666210
########## r/R/extension.R: ########## @@ -0,0 +1,187 @@ +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. + +#' Register Arrow extension types +#' +#' @param extension_name An Arrow extension type name (e.g., arrow.r.vctrs) +#' @param extension_spec An extension specification inheriting from +#' 'nanoarrow_extension_spec'. +#' @param data Optional data to include in the extension type specification +#' @param subclass A subclass for the extension type specification. Extension +#' methods will dispatch on this object. +#' +#' @return +#' - `nanoarrow_extension_spec()` returns an object of class +#' 'nanoarrow_extension_spec'. +#' - `register_nanoarrow_extension()` returns `extension_spec`, invisibly. +#' - `unregister_nanoarrow_extension()` returns `extension_name`, invisibly. +#' - `resolve_nanoarrow_extension()` returns an object of class +#' 'nanoarrow_extension_spec' or NULL if the extension type was not +#' registered. +#' @export +#' +#' @examples +#' nanoarrow_extension_spec("mynamespace.mytype", subclass = "mypackage_mytype_spec") +nanoarrow_extension_spec <- function(data = list(), subclass = character()) { + structure( + data, + class = union(subclass, "nanoarrow_extension_spec") + ) +} + +#' @rdname nanoarrow_extension_spec +#' @export +register_nanoarrow_extension <- function(extension_name, extension_spec) { + extension_registry[[extension_name]] <- extension_spec + invisible(extension_name) +} + +#' @rdname nanoarrow_extension_spec +#' @export +unregister_nanoarrow_extension <- function(extension_name) { + extension_registry[[extension_name]] <- NULL + invisible(extension_name) +} + +#' @rdname nanoarrow_extension_spec +#' @export +resolve_nanoarrow_extension <- function(extension_name) { + extension_registry[[extension_name]] +} + + +#' Implement Arrow extension types +#' +#' @inheritParams nanoarrow_extension_spec +#' @param warn_unregistered Use `FALSE` to infer/convert based on the storage +#' type without a warning. +#' @param x,array,to,schema,... Passed from [infer_nanoarrow_ptype()], +#' [convert_array()], [as_nanoarrow_array()], and/or +#' [as_nanoarrow_array_stream()]. +#' +#' @return +#' - `infer_nanoarrow_ptype_extension()`: The R vector prototype to be used +#' as the default conversion target. +#' - `convert_array_extension()`: An R vector of type `to`. +#' - `as_nanoarrow_array_extension()`: A [nanoarrow_array][as_nanoarrow_array] +#' of type `schema`. +#' @export +#' +infer_nanoarrow_ptype_extension <- function(extension_spec, x, ..., + warn_unregistered = TRUE) { + UseMethod("infer_nanoarrow_ptype_extension") +} + +#' @rdname infer_nanoarrow_ptype_extension +#' @export +convert_array_extension <- function(extension_spec, array, to, ..., + warn_unregistered = TRUE) { + UseMethod("convert_array_extension") +} + +#' @rdname infer_nanoarrow_ptype_extension +#' @export +as_nanoarrow_array_extension <- function(extension_spec, x, ..., schema = NULL) { + UseMethod("as_nanoarrow_array_extension") +} + +#' @export +infer_nanoarrow_ptype_extension.default <- function(extension_spec, x, ..., + warn_unregistered = TRUE) { + if (warn_unregistered) { + warn_unregistered_extension_type(x) + } Review Comment: I *think* so. I suppose the other option is to hard-code the warning somewhere before it gets here? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
