Extract shared pipe injection helper

Author: dannote

lib/ex_dna/ast/normalizer.ex

@@ -34,6 +34,8 @@ defmodule ExDNA.AST.Normalizer do
      and library guards like `Integer.is_even/1`.
   """
 
+  alias ExDNA.AST.Pipe
+
   @type option :: {:literal_mode, :keep | :abstract} | {:normalize_pipes, boolean()}
 
   @doc """
@@ -100,7 +102,7 @@ defmodule ExDNA.AST.Normalizer do
   defp fused_walk({:|>, _meta, [left, right]}, true = pipes, env) do
     {left_n, env} = fused_walk(left, pipes, env)
     {right_n, env} = fused_walk(right, pipes, env)
-    {inject_first_arg(right_n, left_n), env}
+    {Pipe.inject_first_arg(right_n, left_n), env}
   end
 
   # Variable node
@@ -156,20 +158,6 @@ defmodule ExDNA.AST.Normalizer do
     {Enum.reverse(reversed), env}
   end
 
-  # --- Pipe injection (from PipeNormalizer, inlined for the fused walk) ---
-
-  defp inject_first_arg({call, meta, args}, first_arg) when is_list(args) do
-    {call, meta, [first_arg | args]}
-  end
-
-  defp inject_first_arg({call, meta, nil}, first_arg) do
-    {call, meta, [first_arg]}
-  end
-
-  defp inject_first_arg(other, first_arg) do
-    {other, [], [first_arg]}
-  end
-
   # --- Sigil expansion ---
 
   defp expand_sigil_w(content, modifier) do

lib/ex_dna/ast/pipe.ex

@@ -0,0 +1,16 @@
+defmodule ExDNA.AST.Pipe do
+  @moduledoc false
+
+  @spec inject_first_arg(Macro.t(), Macro.t()) :: Macro.t()
+  def inject_first_arg({call, meta, args}, first_arg) when is_list(args) do
+    {call, meta, [first_arg | args]}
+  end
+
+  def inject_first_arg({call, meta, nil}, first_arg) do
+    {call, meta, [first_arg]}
+  end
+
+  def inject_first_arg(other, first_arg) do
+    {other, [], [first_arg]}
+  end
+end

lib/ex_dna/ast/pipe_normalizer.ex

@@ -8,6 +8,8 @@ defmodule ExDNA.AST.PipeNormalizer do
   don't prevent clone detection.
   """
 
+  alias ExDNA.AST.Pipe
+
   @doc """
   Convert all pipe expressions in an AST to nested function calls.
   """
@@ -17,20 +19,8 @@ defmodule ExDNA.AST.PipeNormalizer do
   end
 
   defp flatten_pipe({:|>, _meta, [left, right]}) do
-    inject_first_arg(right, left)
+    Pipe.inject_first_arg(right, left)
   end
 
   defp flatten_pipe(other), do: other
-
-  defp inject_first_arg({call, meta, args}, first_arg) when is_list(args) do
-    {call, meta, [first_arg | args]}
-  end
-
-  defp inject_first_arg({call, meta, nil}, first_arg) do
-    {call, meta, [first_arg]}
-  end
-
-  defp inject_first_arg(other, first_arg) do
-    {other, [], [first_arg]}
-  end
 end