Across evaluated lists

NEWS.md

@@ -1,5 +1,8 @@
 # dbplyr (development version)
 
+* `across()` now works if passing the name of a list of functions to the `.fns`
+  argument (@mgirlich, #817).
+
 * Added translations for lubridate functions `day()`, `week()`, `isoweek()`,
   and `isoyear()` for Postgres (@mgirlich, #675).
 

R/tidyeval-across.R

@@ -28,8 +28,24 @@ across_funs <- function(funs, env, data, dots, names_spec, fn, evaluated = FALSE
   if (is.null(funs)) {
     fns <- list(`1` = function(x, ...) x)
     names_spec <- names_spec %||% "{.col}"
+  } else if (is_quosure(funs)) {
+    return(across_funs(quo_squash(funs), env, data, dots, names_spec, fn, evaluated = evaluated))
   } else if (is_symbol(funs) || is_function(funs) ||
              is_call(funs, "~") || is_call(funs, "function")) {
+    is_local_list <- function(funs) {
+      if (!is_symbol(funs)) {
+        return(FALSE)
+      }
+
+      funs <- as_name(funs)
+      exists(funs, env) && is.list(get(funs, envir = env))
+    }
+
+    if (is_local_list(funs)) {
+      funs <- eval(funs, env)
+      return(across_funs(funs, env, data, dots, names_spec, fn, evaluated = evaluated))
+    }
+
     fns <- list(`1` = across_fun(funs, env, data, dots = dots, fn = fn))
     names_spec <- names_spec %||% "{.col}"
   } else if (is_call(funs, "list")) {

tests/testthat/test-tidyeval-across.R

@@ -321,6 +321,50 @@ test_that("across() translates evaluated lists", {
   )
 })
 
+test_that("across() translates evaluated quosures", {
+  lf <- lazy_frame(a = 1, b = 2)
+
+  expect_equal(
+    capture_across(lf, across(a:b, !!quo(list(log)))),
+    exprs(
+      a_1 = log(a),
+      b_1 = log(b)
+    )
+  )
+
+  expect_equal(
+    capture_across(lf, across(a:b, !!quo(~ log(.x, 2)))),
+    exprs(
+      a = log(a, 2),
+      b = log(b, 2)
+    )
+  )
+
+  expect_equal(
+    capture_across(lf, across(a:b, !!quo(list(log2 = ~ log(.x, 2))))),
+    exprs(
+      a_log2 = log(a, 2),
+      b_log2 = log(b, 2)
+    )
+  )
+})
+
+test_that("across() searches for list in environment", {
+  lf <- lazy_frame(a = 1, b = 2)
+  list_formula <- list(~ log(.x), sum)
+
+  expect_equal(
+    capture_across(lf, across(a:b, list_formula)),
+    exprs(
+      a_1 = log(a),
+      a_2 = sum(a),
+      b_1 = log(b),
+      b_2 = sum(b)
+    )
+  )
+})
+
+
 # if_all ------------------------------------------------------------------
 
 test_that("if_all() translates functions", {