Add support for location specifying in pipe operator

Author: Premwoik

lib/gradient/ast_specifier.ex

@@ -37,7 +37,7 @@ defmodule Gradient.AstSpecifier do
   - binary [X]
   - maps [X]
   - struct [X]
-  - pipe [ ] TODO decide how to search for line in reversed form order 
+  - pipe [X] TODO decide how to search for line in reversed form order
   - range [X] 
   - receive [X] 
   - record [X] 
@@ -55,6 +55,10 @@ defmodule Gradient.AstSpecifier do
   @type form :: Types.form()
   @type forms :: Types.forms()
   @type options :: Types.options()
+  @type abstract_expr :: Types.abstract_expr()
+
+  # Expressions that could have missing location
+  @lineless_forms [:atom, :char, :float, :integer, :string, :bin, :cons]
 
   # Api
 
@@ -364,6 +368,8 @@ defmodule Gradient.AstSpecifier do
 
     name = remote_mapper(name)
 
+    {opts, args} = call_with_pipe_op(tokens, args, opts)
+
     {args, tokens} = context_mapper_fold(args, tokens, opts)
 
     {:call, anno, name, args}
@@ -820,4 +826,33 @@ defmodule Gradient.AstSpecifier do
   defp pass_tokens(form, tokens) do
     {form, tokens}
   end
+
+  @spec call_with_pipe_op(tokens(), [abstract_expr()], options()) :: {options, [abstract_expr]}
+  def call_with_pipe_op(tokens, args, opts) do
+    # Check whether the call is after |> operator. If true, the parent location is set to 0
+    # and the first arg location is cleared (if this arg is a lineless form).
+    # Clearing the location is required only for Elixir 1.13 or newer because from this version
+    # the missing locations are specified, unfortunately sometimes not precise enough.
+    {:ok, line} = Keyword.fetch(opts, :line)
+
+    case {List.first(drop_tokens_to_line(tokens, line)), is_first_arg_lineless?(args)} do
+      {{:arrow_op, _loc, :|>}, true} ->
+        {Keyword.put(opts, :line, 0), clear_first_arg_location(args)}
+
+      _ ->
+        {opts, args}
+    end
+  end
+
+  def is_first_arg_lineless?([form | _]), do: is_lineless_form?(form)
+  def is_first_arg_lineless?([]), do: false
+
+  def is_lineless_form?(form) do
+    elem(form, 0) in @lineless_forms
+  end
+
+  def clear_first_arg_location([form | t]), do: [clear_location(form) | t]
+  def clear_first_arg_location([]), do: []
+
+  def clear_location(form), do: put_elem(form, 1, :erl_anno.set_line(0, elem(form, 1)))
 end

test/gradient/ast_specifier_test.exs

@@ -566,13 +566,13 @@ defmodule Gradient.AstSpecifierTest do
                   [
                     {:call, 4, {:remote, 4, {:atom, 4, Enum}, {:atom, 4, :filter}},
                      [
-                       {:cons, 4, {:integer, 4, 1},
-                        {:cons, 4,
+                       {:cons, 3, {:integer, 3, 1},
+                        {:cons, 3,
                          {
                            :integer,
-                           4,
+                           3,
                            2
-                         }, {:cons, 4, {:integer, 4, 3}, {nil, 4}}}},
+                         }, {:cons, 3, {:integer, 3, 3}, {nil, 3}}}},
                        {:fun, 4,
                         {:clauses,
                          [