jonkeane commented on a change in pull request #8947:
URL: https://github.com/apache/arrow/pull/8947#discussion_r549834792
##########
File path: r/R/expression.R
##########
@@ -173,84 +205,84 @@ Expression <- R6Class("Expression", inherit = ArrowObject,
ToString = function() dataset___expr__ToString(self)
)
)
-
+Expression$create <- function(function_name,
+ ...,
+ args = list(...),
+ options = empty_named_list()) {
+ assert_that(is.string(function_name))
+ dataset___expr__call(function_name, args, options)
+}
Expression$field_ref <- function(name) {
- assert_is(name, "character")
- assert_that(length(name) == 1)
+ assert_that(is.string(name))
dataset___expr__field_ref(name)
}
Expression$scalar <- function(x) {
dataset___expr__scalar(Scalar$create(x))
}
-Expression$compare <- function(OP, e1, e2) {
- comp_func <- comparison_function_map[[OP]]
- if (is.null(comp_func)) {
- stop(OP, " is not a supported comparison function", call. = FALSE)
- }
- comp_func(e1, e2)
-}
-comparison_function_map <- list(
- "==" = dataset___expr__equal,
- "!=" = dataset___expr__not_equal,
- ">" = dataset___expr__greater,
- ">=" = dataset___expr__greater_equal,
- "<" = dataset___expr__less,
- "<=" = dataset___expr__less_equal
-)
-Expression$in_ <- function(x, set) {
- dataset___expr__in(x, Array$create(set))
-}
-Expression$and <- function(e1, e2) {
- dataset___expr__and(e1, e2)
-}
-Expression$or <- function(e1, e2) {
- dataset___expr__or(e1, e2)
-}
-Expression$not <- function(e1) {
- dataset___expr__not(e1)
-}
-Expression$is_valid <- function(e1) {
- dataset___expr__is_valid(e1)
+build_dataset_expression <- function(.Generic, e1, e2, ...) {
+ if (.Generic %in% names(.unary_function_map)) {
+ expr <- Expression$create(.unary_function_map[[.Generic]], e1)
+ } else if (.Generic == "%in%") {
+ # Special-case %in%, which is different from the Array function name
+ expr <- Expression$create("is_in", e1,
+ options = list(
+ value_set = Array$create(e2),
+ skip_nulls = TRUE
+ )
+ )
+ } else {
+ if (!inherits(e1, "Expression")) {
+ e1 <- Expression$scalar(e1)
+ }
+ if (!inherits(e2, "Expression")) {
+ e2 <- Expression$scalar(e2)
+ }
+
+ # In Arrow, "divide" is one function, which does integer division on
+ # integer inputs and floating-point division on floats
+ if (.Generic == "/") {
+ # TODO: omg so many ways it's wrong to assume these types
+ e1 <- Expression$create("cast", e1, options = list(to_type = float64()))
Review comment:
Oh, right, of course. That's nice
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