From 4fd18d308e5d0db99ac989efea8a3069ac30d246 Mon Sep 17 00:00:00 2001
From: Matt Enlow <matt@novaugust.net>
Date: Fri, 26 Jan 2024 10:14:43 -0700
Subject: [PATCH] rewrite all kernel ops inside of |> then

---
 lib/style/pipes.ex | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/lib/style/pipes.ex b/lib/style/pipes.ex
index 0baf93c0..fa77e6af 100644
--- a/lib/style/pipes.ex
+++ b/lib/style/pipes.ex
@@ -32,6 +32,13 @@ defmodule Styler.Style.Pipes do
   @collectable ~w(Map Keyword MapSet)a
   @enum ~w(Enum Stream)a
 
+  # most of these values were lifted directly from credo's pipe_chain_start.ex
+  @literal ~w(__block__ __aliases__ unquote)a
+  @value_constructors ~w(% %{} .. ..// <<>> @ {} ^ & fn from)a
+  @kernel_ops ~w(++ -- && || in - * + / > < <= >= == and or != !== === <>)a
+  @special_ops ~w(<- ||| &&& <<< >>> <<~ ~>> <~ ~> <~> <|> ^^^ ~~~)a
+  @special_ops @literal ++ @value_constructors ++ @kernel_ops ++ @special_ops
+
   def run({{:|>, _, _}, _} = zipper, ctx) do
     case fix_pipe_start(zipper) do
       {{:|>, _, _}, _} = zipper ->
@@ -143,12 +150,6 @@ defmodule Styler.Style.Pipes do
     quote do: {:|>, _, [{:|>, _, [unquote(a), unquote(b)]}, unquote(c)]}
   end
 
-  # Unary operators needs to be expanded (#128)
-  defp maybe_wrap_unary({op, meta, []}) when op in ~w(- +)a,
-    do: {{:., meta, [{:__aliases__, meta, [:Kernel]}, op]}, meta, []}
-
-  defp maybe_wrap_unary(lhs), do: lhs
-
   # a |> fun => a |> fun()
   defp fix_pipe({:|>, m, [lhs, {fun, m2, nil}]}), do: {:|>, m, [lhs, {fun, m2, []}]}
   # a |> then(&fun/1) |> c => a |> fun() |> c()
@@ -158,9 +159,16 @@ defmodule Styler.Style.Pipes do
     rewrite = {fun, m2, args}
 
     # if `&1` is referenced more than once, we have to continue using `then`
-    if rewrite |> Zipper.zip() |> Zipper.any?(&match?({:&, _, _}, &1)),
-      do: pipe,
-      else: {:|>, m, [lhs, maybe_wrap_unary(rewrite)]}
+    cond do
+      rewrite |> Zipper.zip() |> Zipper.any?(&match?({:&, _, _}, &1)) ->
+        pipe
+
+      fun in @special_ops ->
+        if fun in @kernel_ops, do: {:|>, m, [lhs, {{:., m2, [{:__aliases__, m2, [:Kernel]}, fun]}, m2, args}]}, else: pipe
+
+      true ->
+        {:|>, m, [lhs, rewrite]}
+    end
   end
 
   # Credo.Check.Readability.PipeIntoAnonymousFunctions
@@ -272,14 +280,7 @@ defmodule Styler.Style.Pipes do
 
   defp fix_pipe(node), do: node
 
-  # most of these values were lifted directly from credo's pipe_chain_start.ex
-  @literal ~w(__block__ __aliases__ unquote)a
-  @value_constructors ~w(% %{} .. ..// <<>> @ {} ^ & fn from)a
-  @infix_ops ~w(++ -- && || in - * + / > < <= >= == and or != !== ===)a
-  @binary_ops ~w(<> <- ||| &&& <<< >>> <<~ ~>> <~ ~> <~> <|> ^^^ ~~~)a
-  @valid_starts @literal ++ @value_constructors ++ @infix_ops ++ @binary_ops
-
-  defp valid_pipe_start?({op, _, _}) when op in @valid_starts, do: true
+  defp valid_pipe_start?({op, _, _}) when op in @special_ops, do: true
   # 0-arity Module.function_call()
   defp valid_pipe_start?({{:., _, _}, _, []}), do: true
   # Exempt ecto's `from`