[GitHub] [arrow] ianmcook commented on a change in pull request #10722: ARROW-13344: [R] Initial bindings for ExecPlan/ExecNode

[GitBox <gi...@apache.org>]

ianmcook commented on a change in pull request #10722:
URL: https://github.com/apache/arrow/pull/10722#discussion_r677919540



##########
File path: r/R/dplyr-summarize.R
##########
@@ -28,14 +28,109 @@ summarise.arrow_dplyr_query <- function(.data, ..., .engine = c("arrow", "duckdb
     dplyr::group_vars(.data)             # vars needed for grouping
   ))
   .data <- dplyr::select(.data, vars_to_keep)
-
   if (match.arg(.engine) == "duckdb") {
-    dplyr::summarise(to_duckdb(.data), ...)
-  } else {
-    if (query_on_dataset(.data)) {
-      not_implemented_for_dataset("summarize()")
+      dplyr::summarise(to_duckdb(.data), ...)
+  } else if (isTRUE(getOption("arrow.summarize", FALSE))) {
+    # Try stuff, if successful return()
+    out <- try(do_arrow_summarize(.data, ...), silent = TRUE)
+    if (inherits(out, "try-error")) {
+      return(abandon_ship(call, .data, format(out)))
+    } else {
+      return(out)
     }
+  } else {
+    # If unsuccessful or if option not set, do the work in R
     dplyr::summarise(dplyr::collect(.data), ...)
   }
 }
 summarise.Dataset <- summarise.ArrowTabular <- summarise.arrow_dplyr_query
+
+do_arrow_summarize <- function(.data, ...) {
+  exprs <- quos(...)
+  # Check for unnamed expressions and fix if any
+  unnamed <- !nzchar(names(exprs))
+  # Deparse and take the first element in case they're long expressions
+  names(exprs)[unnamed] <- map_chr(exprs[unnamed], as_label)
+
+  mask <- arrow_mask(.data)
+  # Add aggregation wrappers to arrow_mask somehow

Review comment:
       In dbplyr, aggregate function mappings are defined in a separate object apart from the scalar function mappings. I believe it's set up so the scalar functions are defined in a child environment that has a parent environment with the scalar function mappings defined in it, and the R environment lookup rules make it so when you pass the child environment as the mask, it will only ever use the parent environment if it can't find a function in the child environment.




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