From 32620dfd5234be196e0abd4eaf7ecae51427e6a7 Mon Sep 17 00:00:00 2001
From: Zach Daniel <zach@zachdaniel.dev>
Date: Sat, 7 Oct 2023 09:16:52 -0400
Subject: [PATCH] improvement: add `Ash.Sort.expr_sort`. In 3.0 sort should be
 a macro

---
 lib/ash/sort/sort.ex       | 17 +++++++++++++++++
 test/actions/read_test.exs |  9 +++++++++
 2 files changed, 26 insertions(+)

diff --git a/lib/ash/sort/sort.ex b/lib/ash/sort/sort.ex
index 3247714b..b7fd9e71 100644
--- a/lib/ash/sort/sort.ex
+++ b/lib/ash/sort/sort.ex
@@ -24,6 +24,23 @@ defmodule Ash.Sort do
 
   alias Ash.Error.Query.{InvalidSortOrder, NoSuchAttribute}
 
+  defmacro expr_sort(expression, type \\ nil) do
+    quote do
+      require Ash.Expr
+      type = unquote(type)
+
+      case Ash.Query.Calculation.new(
+             :expr_sort,
+             Ash.Resource.Calculation.Expression,
+             [expr: Ash.Expr.expr(unquote(expression))],
+             type && Ash.Type.get_type(type)
+           ) do
+        {:ok, calc} -> calc
+        {:error, term} -> raise Ash.Error.to_ash_error(term)
+      end
+    end
+  end
+
   @doc """
   A utility for parsing sorts provided from external input. Only allows sorting
   on public attributes and aggregates.
diff --git a/test/actions/read_test.exs b/test/actions/read_test.exs
index 4a6771de..62d7d3e5 100644
--- a/test/actions/read_test.exs
+++ b/test/actions/read_test.exs
@@ -586,6 +586,15 @@ defmodule Ash.Test.Actions.ReadTest do
                |> Api.read()
                |> strip_metadata()
     end
+
+    test "a sort can use an expression", %{post1: post1, post2: post2} do
+      require Ash.Sort
+
+      Post
+      |> Ash.Query.sort([{Ash.Sort.expr_sort(title <> contents), :asc}])
+      |> Api.read!()
+      |> IO.inspect()
+    end
   end
 
   describe "get_by with only a single field" do