Selection ranges porvider (#1060)

* selection ranges porvider

* handle structs

add range operation unit tests

* , and case

* wip

* wip

* more cases covered

* improve compatibility

* add comments on workaround

* resolve todo

* move function

* increase compatibility

* handle one more case

* improve compatibility

* increase compatibility

* do not run failing tests on old elixir versions

* fix an edge case when reduced range may no longer contain cursor

* use function

* don't run on < 1.14

* resolve some todos

* handle access

* address todos

* add test

* don't run test on 1.12

* add assert

* add comments

* remove IO.inspect

apps/language_server/lib/language_server/protocol.ex

@@ -181,6 +181,15 @@ defmodule ElixirLS.LanguageServer.Protocol do
     end
   end
 
+  defmacro selection_range_req(id, uri, positions) do
+    quote do
+      request(unquote(id), "textDocument/selectionRange", %{
+        "textDocument" => %{"uri" => unquote(uri)},
+        "positions" => unquote(positions)
+      })
+    end
+  end
+
   defmacro execute_command_req(id, command, arguments) do
     quote do
       request(unquote(id), "workspace/executeCommand", %{

apps/language_server/lib/language_server/providers/folding_range/comment_block.ex

@@ -38,13 +38,14 @@ defmodule ElixirLS.LanguageServer.Providers.FoldingRange.CommentBlock do
     ranges =
       lines
       |> group_comments()
+      |> Enum.filter(fn group -> length(group) > 1 end)
       |> Enum.map(&convert_comment_group_to_range/1)
 
     {:ok, ranges}
   end
 
   @spec group_comments([Line.t()]) :: [[{Line.cell(), String.t()}]]
-  defp group_comments(lines) do
+  def group_comments(lines) do
     lines
     |> Enum.reduce([[]], fn
       {_, cell, "#"}, [[{_, "#"} | _] = head | tail] ->
@@ -59,7 +60,6 @@ defmodule ElixirLS.LanguageServer.Providers.FoldingRange.CommentBlock do
       _, acc ->
         acc
     end)
-    |> Enum.filter(fn group -> length(group) > 1 end)
   end
 
   @spec convert_comment_group_to_range([[{Line.cell(), String.t()}]]) :: FoldingRange.t()

apps/language_server/lib/language_server/providers/folding_range/indentation.ex

@@ -53,7 +53,7 @@ defmodule ElixirLS.LanguageServer.Providers.FoldingRange.Indentation do
     {:ok, ranges}
   end
 
-  defp extract_cell({_line, cell, _first}), do: cell
+  def extract_cell({_line, cell, _first}), do: cell
 
   @doc """
   Pairs cells into {start, end} tuples of regions

apps/language_server/lib/language_server/providers/folding_range/special_token.ex

@@ -56,27 +56,33 @@ defmodule ElixirLS.LanguageServer.Providers.FoldingRange.SpecialToken do
   end
 
   @spec group_tokens([Token.t()]) :: [[Token.t()]]
-  defp group_tokens(tokens) do
+  def group_tokens(tokens) do
     do_group_tokens(tokens, [])
   end
 
   defp do_group_tokens([], acc), do: acc
 
-  # Don't create folding ranges for docs
-  defp do_group_tokens([{:identifier, _, doc_identifier}, {false, _, _} | rest], acc)
+  # Don't create folding ranges for @doc false
+  defp do_group_tokens(
+         [{:at_op, _, _}, {:identifier, _, doc_identifier}, {false, _, _} | rest],
+         acc
+       )
        when doc_identifier in @docs do
     do_group_tokens(rest, acc)
   end
 
   # Start a folding range for `@doc` and `@moduledoc`
-  defp do_group_tokens([{:identifier, _, doc_identifier} = token | rest], acc)
+  defp do_group_tokens(
+         [{:at_op, _, _} = at_op, {:identifier, _, doc_identifier} = token | rest],
+         acc
+       )
        when doc_identifier in @docs do
-    acc = [[token] | acc]
+    acc = [[token, at_op] | acc]
     do_group_tokens(rest, acc)
   end
 
   # Amend the folding range
-  defp do_group_tokens([{k, _, _} = token | rest], [[{:identifier, _, _}] = head | tail])
+  defp do_group_tokens([{k, _, _} = token | rest], [[{:identifier, _, _} | _] = head | tail])
        when k in @kinds do
     acc = [[token | head] | tail]
     do_group_tokens(rest, acc)
@@ -118,7 +124,7 @@ defmodule ElixirLS.LanguageServer.Providers.FoldingRange.SpecialToken do
   end
 
   defp classify_group({kind, {start_line, _, _}, _}, {_, {end_line, _, _}, _}) do
-    kind = if kind == :identifier, do: :comment, else: :region
+    kind = if kind == :at_op, do: :comment, else: :region
     {start_line, end_line, kind}
   end
 end

apps/language_server/lib/language_server/providers/folding_range/token_pairs.ex

@@ -58,7 +58,7 @@ defmodule ElixirLS.LanguageServer.Providers.FoldingRange.TokenPair do
   end
 
   @spec pair_tokens([Token.t()]) :: [{Token.t(), Token.t()}]
-  defp pair_tokens(tokens) do
+  def pair_tokens(tokens) do
     do_pair_tokens(tokens, [], [])
   end
 
@@ -82,8 +82,8 @@ defmodule ElixirLS.LanguageServer.Providers.FoldingRange.TokenPair do
          pairs
        ) do
     head_matches_any? = @token_pairs |> Map.has_key?(head_kind)
-    # Map.get/2 will always succeed because we only push matches to the stack.
-    head_matches_top? = @token_pairs |> Map.get(top_kind) |> Enum.member?(head_kind)
+    # Map.fetch!/2 will always succeed because we only push matches to the stack.
+    head_matches_top? = @token_pairs |> Map.fetch!(top_kind) |> Enum.member?(head_kind)
 
     {new_stack, new_pairs} =
       case {head_matches_any?, head_matches_top?} do