fix/add date-related functions

R/backend-dbplyr__duckdb_connection.R

@@ -307,6 +307,16 @@ sql_translation.duckdb_connection <- function(con) {
         build_sql("DATEDIFF('day', ", !!start, ", " ,!!end, ")")
 
       },
+      date_build = function(year, month = 1L, day = 1L, ..., invalid = NULL) {
+        check_unsupported_arg(invalid, allow_null = TRUE)
+        rlang::check_dots_empty()
+        dbplyr::sql_expr(MAKE_DATE(!!year, !!month, !!day))
+      },
+      difftime = function(time1, time2, tz, units = "days") {
+        check_unsupported_arg(tz)
+        check_unsupported_arg(units, allowed = "days")
+        dbplyr::sql_expr(DATEDIFF("day", !!time2, !!time1))
+      },
 
       # stringr functions
       str_c = sql_paste(""),

R/check_unsupported_arg.R

@@ -0,0 +1,50 @@
+#' Check for unsupported argument values
+#'
+#' The function checks whether a given argument is unsupported
+#' It throws an error message if the argument is not among the allowed values.
+#' Function is taken from dplyr.
+#'
+#' @param x The argument to check.
+#' @param allowed A value or vector of values that are allowed for `x`. If `NULL`, no value is allowed.
+#' @param allow_null Logical. If `TRUE`, allows `x` to be `NULL`.
+#' @param backend Optional character string indicating the back-end.
+#' @param arg The name of the argument being checked (automatically inferred via `rlang::caller_arg()`).
+#' @param call The calling environment used for error reporting (automatically inferred via `rlang::caller_env()`).
+#'
+#' @noRd
+check_unsupported_arg <- function (x, allowed = NULL, allow_null = FALSE, backend = NULL,
+                                   arg = caller_arg(x), call = caller_env())
+{
+  if (rlang::is_missing(x)) {
+    return()
+  }
+  if (allow_null && rlang::is_null(x)) {
+    return()
+  }
+  if (identical(x, allowed)) {
+    return()
+  }
+  if (rlang::is_null(allowed)) {
+    msg <- "Argument {.arg {arg}} isn't supported"
+  }
+  else {
+    msg <- "{.code {arg} = {.val {x}}} isn't supported"
+  }
+  if (is.null(backend)) {
+    msg <- paste0(msg, " on database backends.")
+  }
+  else {
+    msg <- paste0(msg, " in {backend} translation.")
+  }
+  if (!rlang::is_null(allowed)) {
+    if (allow_null) {
+      allow_msg <- "It must be {.val {allowed}} or {.code NULL} instead."
+    }
+    else {
+      allow_msg <- "It must be {.val {allowed}} instead."
+    }
+    msg <- c(msg, i = allow_msg)
+  }
+  cli_abort(msg, call = call)
+}
+

tests/testthat/test-backend-dbplyr__duckdb_connection.R

@@ -152,6 +152,10 @@ test_that("custom clock functions translated correctly", {
                                             precision = "day")),
                sql(r"{DATEDIFF('day', start, end)}"))
 
+  expect_equal(translate(difftime(time1 = "time1", time2 = "time2", units = "days")), sql(r"{DATEDIFF('day', 'time2', 'time1')}"))
+  expect_equal(translate(date_build(year = 2000L, month = 8L, day = 8L)), sql(r"{MAKE_DATE(2000, 8, 8)}"))
+  expect_equal(translate(date_build(year = 2000)), sql(r"{MAKE_DATE(2000.0, 1, 1)}"))
+
   test_data <- data.frame(
     person = 1L,
     date_1 = as.Date("2000-01-01"),
@@ -193,6 +197,9 @@ test_that("custom clock functions translated correctly", {
                                             precision = "day",
                                             n = 5)))
 
+  expect_error(translate(date_build(year = 2000, month = 08, day = 08, invalid = "next-day")))
+  expect_error(translate(difftime(time1, time2, units = "secs")))
+  expect_error(translate(difftime(time1, time2, tz = Sys.timezone())))
 })
 
 # stringr functions