improvement: add like and ilike

lib/data_layer.ex

@@ -625,7 +625,11 @@ defmodule AshPostgres.DataLayer do
   def functions(resource) do
     config = AshPostgres.DataLayer.Info.repo(resource).config()
 
-    functions = [AshPostgres.Functions.Fragment]
+    functions = [
+      AshPostgres.Functions.Fragment,
+      AshPostgres.Functions.Like,
+      AshPostgres.Functions.ILike
+    ]
 
     if "pg_trgm" in (config[:installed_extensions] || []) do
       functions ++

lib/expr.ex

@@ -5,7 +5,7 @@ defmodule AshPostgres.Expr do
   alias Ash.Query.{BooleanExpression, Exists, Not, Ref}
   alias Ash.Query.Operator.IsNil
   alias Ash.Query.Function.{Ago, Contains, GetPath, If, Length, Now, Type}
-  alias AshPostgres.Functions.{Fragment, TrigramSimilarity}
+  alias AshPostgres.Functions.{Fragment, ILike, Like, TrigramSimilarity}
 
   require Ecto.Query
 
@@ -51,6 +51,34 @@ defmodule AshPostgres.Expr do
     |> maybe_type(type, query)
   end
 
+  defp do_dynamic_expr(
+         query,
+         %Like{arguments: [arg1, arg2], embedded?: pred_embedded?},
+         bindings,
+         embedded?,
+         type
+       ) do
+    arg1 = do_dynamic_expr(query, arg1, bindings, pred_embedded? || embedded?)
+    arg2 = do_dynamic_expr(query, arg2, bindings, pred_embedded? || embedded?)
+
+    Ecto.Query.dynamic(like(^arg1, ^arg2))
+    |> maybe_type(type, query)
+  end
+
+  defp do_dynamic_expr(
+         query,
+         %ILike{arguments: [arg1, arg2], embedded?: pred_embedded?},
+         bindings,
+         embedded?,
+         type
+       ) do
+    arg1 = do_dynamic_expr(query, arg1, bindings, pred_embedded? || embedded?)
+    arg2 = do_dynamic_expr(query, arg2, bindings, pred_embedded? || embedded?)
+
+    Ecto.Query.dynamic(ilike(^arg1, ^arg2))
+    |> maybe_type(type, query)
+  end
+
   defp do_dynamic_expr(
          query,
          %IsNil{left: left, right: right, embedded?: pred_embedded?},

lib/functions/ilike.ex

@@ -0,0 +1,9 @@
+defmodule AshPostgres.Functions.ILike do
+  @moduledoc """
+  Maps to the builtin postgres function `ilike`.
+  """
+
+  use Ash.Query.Function, name: :ilike
+
+  def args, do: [[:string, :string]]
+end

lib/functions/like.ex

@@ -0,0 +1,9 @@
+defmodule AshPostgres.Functions.Like do
+  @moduledoc """
+  Maps to the builtin postgres function `like`.
+  """
+
+  use Ash.Query.Function, name: :like
+
+  def args, do: [[:string, :string]]
+end

test/filter_test.exs

@@ -773,6 +773,48 @@ defmodule AshPostgres.FilterTest do
     end
   end
 
+  describe "like and ilike" do
+    test "like builds and matches" do
+      Post
+      |> Ash.Changeset.new(%{title: "MaTcH"})
+      |> Api.create!()
+
+      results =
+        Post
+        |> Ash.Query.filter(like(title, "%aTc%"))
+        |> Api.read!()
+
+      assert [%Post{title: "MaTcH"}] = results
+
+      results =
+        Post
+        |> Ash.Query.filter(like(title, "%atc%"))
+        |> Api.read!()
+
+      assert [] = results
+    end
+
+    test "ilike builds and matches" do
+      Post
+      |> Ash.Changeset.new(%{title: "MaTcH"})
+      |> Api.create!()
+
+      results =
+        Post
+        |> Ash.Query.filter(ilike(title, "%aTc%"))
+        |> Api.read!()
+
+      assert [%Post{title: "MaTcH"}] = results
+
+      results =
+        Post
+        |> Ash.Query.filter(ilike(title, "%atc%"))
+        |> Api.read!()
+
+      assert [%Post{title: "MaTcH"}] = results
+    end
+  end
+
   describe "trigram_similarity" do
     test "it works on matches" do
       Post