Add vctrs methods (#247)

* move to dynamic S3 registration onLoad

* Add self-to-self coercion methods

* Add proxy and restore for units vectors

* Add integration test with dplyr

Co-authored-by: Iñaki Úcar <iucar@fedoraproject.org>

DESCRIPTION

@@ -14,6 +14,7 @@ Imports:
 LinkingTo:
 	Rcpp (>= 0.12.10)
 Suggests:
+    dplyr (>= 1.0.0),
 	udunits2,
     NISTunits,
     measurements,
@@ -24,7 +25,8 @@ Suggests:
     testthat,
 	ggforce,
 	rmarkdown,
-    magrittr
+    magrittr,
+    vctrs (>= 0.3.1)
 VignetteBuilder: knitr
 Description: Support for measurement units in R vectors, matrices
 	and arrays: automatic propagation, conversion, derivation

NAMESPACE

@@ -87,19 +87,6 @@ export(unitless)
 export(units_options)
 export(valid_udunits)
 export(valid_udunits_prefixes)
-if(getRversion() >= "3.6.0") {
-  S3method(pillar::type_sum, units)
-  S3method(pillar::type_sum, mixed_units)
-  S3method(pillar::pillar_shaft, units)
-  S3method(pillar::pillar_shaft, mixed_units)
-  S3method(pillar::format_type_sum, type_sum_units)
-} else {
-  export(type_sum.units)
-  export(type_sum.mixed_units)
-  export(pillar_shaft.units)
-  export(pillar_shaft.mixed_units)
-  export(format_type_sum.type_sum_units)
-}
 import(graphics)
 import(stats)
 import(utils)

NEWS.md

@@ -4,6 +4,8 @@
 
 * fix replacement operation for `units` objects; #233 addressing #232
 
+* fix compatibility with dplyr 1.0; #247 addressing #239
+
 # version 0.6-6
 
 * prettier `str` print for units and mixed units; #228 addressing #227

R/init.R

@@ -15,6 +15,8 @@ NULL
   else if (l10n_info()[["Latin-1"]]) "latin1"
   else "ascii"
   ud_set_encoding(native)
+
+  register_all_s3_methods()
 }
 
 .onAttach <- function(libname, pkgname) {

R/misc.R

@@ -114,48 +114,6 @@ seq.units = function(from, to, by = ((to - from)/(length.out - 1)),
   set_units(NextMethod(), uuu, mode = "standard")
 }
 
-#' type_sum function for units
-#' @name tibble
-#' @param x see \link[pillar]{type_sum}
-#' @param ... see \link[pillar]{type_sum}
-#' @rawNamespace if(getRversion() >= "3.6.0") {
-#'   S3method(pillar::type_sum, units)
-#'   S3method(pillar::type_sum, mixed_units)
-#'   S3method(pillar::pillar_shaft, units)
-#'   S3method(pillar::pillar_shaft, mixed_units)
-#'   S3method(pillar::format_type_sum, type_sum_units)
-#' } else {
-#'   export(type_sum.units)
-#'   export(type_sum.mixed_units)
-#'   export(pillar_shaft.units)
-#'   export(pillar_shaft.mixed_units)
-#'   export(format_type_sum.type_sum_units)
-#' }
-type_sum.units <- function(x, ...) {
-  gr = units_options("group")
-  # see https://github.com/r-lib/pillar/issues/73 : currently the [ and ] mess up things.
-  structure(paste0(gr[1], as.character(units(x)), gr[2]),
-    class = "type_sum_units")
-}
-#' @name tibble
-#' @param width ignored
-format_type_sum.type_sum_units <- function(x, width, ...) {
-  if (! requireNamespace("pillar", quietly = TRUE))
-    stop("package pillar not available: install first?")
-  pillar::style_subtle(x)
-}
-
-#' pillar_shaft function for units
-#' @name tibble
-pillar_shaft.units <- function(x, ...) {
-  u_char <- as.character(units(x))
-  if (! requireNamespace("pillar", quietly = TRUE))
-    stop("package pillar not available: install first?")
-  #out <- paste(format(unclass(x), ...), pillar::style_subtle(u_char))
-  out <- format(unclass(x), ...)
-  pillar::new_pillar_shaft_simple(out, align = "right", min_width = 8)
-}
-
 #' @export
 str.units = function(object, ...) {
   gr <- units_options("group")

R/mixed.R

@@ -121,16 +121,3 @@ Ops.mixed_units = function(e1, e2) {
 		ret = .as.mixed_units(ret)
 	ret
 }
-
-#' @name tibble
-type_sum.mixed_units <- function(x, ...) {
-  "mixed_units" 
-}
-
-#' @name tibble
-pillar_shaft.mixed_units <- function(x, ...) {
-  if (! requireNamespace("pillar", quietly = TRUE))
-    stop("package pillar not available: install first?")
-  out <- format(x, ...)
-  pillar::new_pillar_shaft_simple(out, align = "right", min_width = 6)
-}

R/tidyverse.R

@@ -0,0 +1,115 @@
+type_sum.units <- function(x, ...) {
+  gr = units_options("group")
+  # see https://github.com/r-lib/pillar/issues/73 : currently the [ and ] mess up things.
+  structure(paste0(gr[1], as.character(units(x)), gr[2]),
+            class = "type_sum_units")
+}
+
+type_sum.mixed_units <- function(x, ...) {
+  "mixed_units" 
+}
+
+pillar_shaft.units <- function(x, ...) {
+  u_char <- as.character(units(x))
+  if (! requireNamespace("pillar", quietly = TRUE))
+    stop("package pillar not available: install first?")
+  #out <- paste(format(unclass(x), ...), pillar::style_subtle(u_char))
+  out <- format(unclass(x), ...)
+  pillar::new_pillar_shaft_simple(out, align = "right", min_width = 8)
+}
+
+pillar_shaft.mixed_units <- function(x, ...) {
+  if (! requireNamespace("pillar", quietly = TRUE))
+    stop("package pillar not available: install first?")
+  out <- format(x, ...)
+  pillar::new_pillar_shaft_simple(out, align = "right", min_width = 6)
+}
+
+format_type_sum.type_sum_units <- function(x, width, ...) {
+  if (! requireNamespace("pillar", quietly = TRUE))
+    stop("package pillar not available: install first?")
+  pillar::style_subtle(x)
+}
+
+
+# vctrs proxying and restoration -------------------------------------
+
+vec_proxy.units = function(x, ...) {
+  x
+}
+vec_restore.units = function(x, to, ...) {
+  set_units(x, units(to), mode = "standard")
+}
+
+
+# vctrs coercion -----------------------------------------------------
+
+vec_ptype2.units.units = function(x, y, ..., x_arg = "", y_arg = "") {
+  x_units = units(x)
+  y_units = units(y)
+
+  if (!ud_are_convertible(x_units, y_units))
+    vctrs::stop_incompatible_type(x, y, x_arg = x_arg, y_arg = y_arg)
+
+  x_bare = drop_units(x)
+  y_bare = drop_units(y)
+  common = vctrs::vec_ptype2(x_bare, y_bare, ..., x_arg = x_arg, y_arg = y_arg)
+
+  # Use left-hand side units
+  set_units(common, x_units, mode = "standard")
+}
+
+vec_cast.units.units = function(x, to, ..., x_arg = "", to_arg = "") {
+  x_units = units(x)
+  to_units = units(to)
+
+  if (!ud_are_convertible(x_units, to_units))
+    vctrs::stop_incompatible_cast(x, to, x_arg = x_arg, to_arg = to_arg)
+
+  # Convert to target units before converting base type. Unit
+  # conversion might change the type and so must happen first.
+  out = set_units(x, to_units, mode = "standard")
+
+  out_bare = drop_units(out)
+  to_bare = drop_units(to)
+  out = vctrs::vec_cast(out_bare, to_bare, ..., x_arg = x_arg, to_arg = to_arg)
+
+  # Set target units again
+  set_units(out, to_units, mode = "standard")
+}
+
+
+#nocov start
+register_all_s3_methods <- function() {
+  register_s3_method("pillar::type_sum", "units")
+  register_s3_method("pillar::type_sum", "mixed_units")
+  register_s3_method("pillar::pillar_shaft", "units")
+  register_s3_method("pillar::pillar_shaft", "mixed_units")
+  register_s3_method("pillar::format_type_sum", "type_sum_units")
+  register_s3_method("vctrs::vec_proxy", "units")
+  register_s3_method("vctrs::vec_restore", "units")
+  register_s3_method("vctrs::vec_ptype2", "units.units")
+  register_s3_method("vctrs::vec_cast", "units.units")
+}
+
+register_s3_method <- function(generic, class, fun=NULL) {
+  stopifnot(is.character(generic), length(generic) == 1)
+  stopifnot(is.character(class), length(class) == 1)
+
+  pieces <- strsplit(generic, "::")[[1]]
+  stopifnot(length(pieces) == 2)
+  package <- pieces[[1]]
+  generic <- pieces[[2]]
+
+  if (is.null(fun))
+    fun <- get(paste0(generic, ".", class), envir=parent.frame())
+  stopifnot(is.function(fun))
+
+  if (package %in% loadedNamespaces())
+    registerS3method(generic, class, fun, envir=asNamespace(package))
+
+  # Always register hook in case package is later unloaded & reloaded
+  setHook(packageEvent(package, "onLoad"), function(...)
+    registerS3method(generic, class, fun, envir=asNamespace(package)))
+}
+# nocov end

tests/testthat/test_tidyverse.R

@@ -0,0 +1,82 @@
+
+skip_if_not_installed("vctrs")
+
+test_that("units have coercion methods", {
+  x = set_units(1:3, "cm")
+  y = set_units(4.0, "m")
+  z = set_units(10, "celsius")
+
+  expect_error(vctrs::vec_ptype_common(y, x, z), class = "vctrs_error_incompatible_type")
+  expect_error(vctrs::vec_cast_common(y, x, z), class = "vctrs_error_incompatible_type")
+
+  expect_identical(vctrs::vec_ptype_common(x, y, x), set_units(double(), "cm"))
+  expect_identical(vctrs::vec_ptype_common(x, x), set_units(integer(), "cm"))
+  expect_identical(vctrs::vec_ptype_common(y, x, x), set_units(double(), "m"))
+
+  expect_identical(
+    vctrs::vec_cast_common(x, y),
+    list(set_units(c(1, 2, 3), "cm"), set_units(400, "cm"))
+  )
+  expect_identical(
+    vctrs::vec_cast_common(y, x),
+    list(set_units(4, "m"), set_units(c(0.01, 0.02, 0.03), "m"))
+  )
+
+  # Casting to integer with fractional cm is lossy
+  expect_error(
+    vctrs::vec_cast_common(y, x, .to = set_units(0L, "m")),
+    class = "vctrs_error_cast_lossy"
+  )
+})
+
+test_that("can combine units vectors", {
+  x <- set_units(1:3, "cm")
+  y <- set_units(4, "m")
+
+  exp = set_units(c(1, 2, 3, 400), "cm")
+  expect_identical(vctrs::vec_c(x, y), exp)
+
+  # Recursive case
+  df1 = tibble::tibble(x = tibble::tibble(x = x))
+  df2 = tibble::tibble(x = tibble::tibble(x = y))
+  df_exp = tibble::tibble(x = tibble::tibble(x = exp))
+  expect_identical(vctrs::vec_c(df1, df2), df_exp)
+})
+
+test_that("can slice units vectors", {
+  x = set_units(1:3, "cm")
+  exp = list(set_units(1L, "cm"), set_units(2L, "cm"), set_units(3L, "cm"))
+  expect_identical(vctrs::vec_chop(x), exp)
+
+  # Recursive case
+  df = tibble::tibble(tibble::tibble(x = x))
+  exp = list(
+    tibble::tibble(x = set_units(1L, "cm")),
+    tibble::tibble(x = set_units(2L, "cm")),
+    tibble::tibble(x = set_units(3L, "cm"))
+  )
+  expect_identical(vctrs::vec_chop(df), exp)
+})
+
+
+skip_if_not_installed("dplyr")
+
+`%>%` <- dplyr::`%>%`
+
+test_that("split-apply-combine with dplyr and base agree", {
+  iris2 <- iris
+  for (i in 1:4)
+    units(iris2[,i]) <- "cm"
+
+  out <- iris2 %>%
+    dplyr::group_by(Species) %>%
+    dplyr::summarise(dplyr::across(where(is.numeric), mean))
+
+  # Transform to list of lists
+  out <- vctrs::vec_chop(out[2:5]) %>%
+    stats::setNames(out$Species) %>%
+    lapply(as.list)
+
+  exp <- lapply(split(iris2[1:4], iris2$Species), lapply, mean)
+  expect_equal(out, exp)
+})