[Request for Feedback] Add ontype formatting support

apps/els_core/include/els_core.hrl

@@ -548,8 +548,8 @@
                                }.
 
 -type document_ontypeformatting_options() :: false |
-       #{ first_trigger_character := string()
-        , more_trigger_character  => string()
+       #{ firstTriggerCharacter := binary()
+        , moreTriggerCharacter  => [binary()]
         }.
 
 %%------------------------------------------------------------------------------
@@ -612,7 +612,8 @@
                    | {atom(), atom()} %% record_def_field, record_field
                    | string() %% include, include_lib
                    | {atom(), arity()}
-                   | {module(), atom(), arity()}.
+                   | {module(), atom(), arity()}
+                   | pos().
 -type poi()       :: #{ kind  := poi_kind()
                       , id    := poi_id()
                       , data  := any()

apps/els_core/src/els_client.erl

@@ -455,6 +455,10 @@ request_params({initialize, {RootUri, InitOptions}}) ->
                      }
                   , <<"hover">> =>
                     #{ <<"contentFormat">> => ContentFormat }
+                  , <<"documentOnTypeFormattingProvider">> =>
+                      #{ firstTriggerCharacter => <<",">>
+                       , moreTriggercharacter => []
+                       }
                   },
   #{ <<"rootUri">> => RootUri
    , <<"initializationOptions">> => InitOptions

apps/els_core/src/els_config.erl

@@ -134,6 +134,7 @@ do_initialize(RootUri, Capabilities, InitOptions, {ConfigPath, Config}) ->
     = maps:get("compiler_telemetry_enabled", Config, false),
 
   IndexingEnabled = maps:get(<<"indexingEnabled">>, InitOptions, true),
+  FormatOnTypeEnabled = maps:get("format_on_type", Config, false),
 
   %% Passed by the LSP client
   ok = set(root_uri       , RootUri),
@@ -147,6 +148,7 @@ do_initialize(RootUri, Capabilities, InitOptions, {ConfigPath, Config}) ->
   ok = set(macros         , Macros),
   ok = set(plt_path       , DialyzerPltPath),
   ok = set(code_reload    , CodeReload),
+  ok = set(format_on_type , FormatOnTypeEnabled),
   ?LOG_INFO("Config=~p", [Config]),
   ok = set(runtime, maps:merge( els_config_runtime:default_config()
                               , Runtime)),

apps/els_lsp/src/els_dt_document.erl

@@ -21,15 +21,16 @@
         , lookup/1
         ]).
 
--export([ new/2
+-export([ get_element_at_pos/3
+        , new/2
         , pois/1
         , pois/2
-        , get_element_at_pos/3
         , uri/1
         , functions_at_pos/3
         , applications_at_pos/3
         , wrapping_functions/2
         , wrapping_functions/3
+        , text/1
         ]).
 
 %%==============================================================================
@@ -63,6 +64,7 @@
                  , md5  => binary()
                  , pois => [poi()]
                  }.
+
 -export_type([ id/0
              , item/0
              , kind/0
@@ -155,6 +157,10 @@ new(Uri, Text, Id, Kind) ->
 pois(#{ pois := POIs }) ->
   POIs.
 
+-spec text(item()) -> binary().
+text(#{text := Text}) ->
+  Text.
+
 %% @doc Returns the list of POIs of the given types for the current
 %%      document
 -spec pois(item(), [poi_kind()]) -> [poi()].

apps/els_lsp/src/els_formatting_provider.erl

@@ -49,13 +49,17 @@ is_enabled_document() -> true.
 
 -spec is_enabled_range() -> boolean().
 is_enabled_range() ->
-  false.
+  true.
 
 %% NOTE: because erlang_ls does not send incremental document changes
 %%       via `textDocument/didChange`, this kind of formatting does not
 %%       make sense.
 -spec is_enabled_on_type() -> document_ontypeformatting_options().
-is_enabled_on_type() -> false.
+is_enabled_on_type() ->
+  case els_config:get(format_on_type) of
+    true -> #{firstTriggerCharacter => <<".">>, moreTriggerCharacter => []};
+    false -> false
+  end.
 
 -spec handle_request(any(), state()) -> {any(), state()}.
 handle_request({document_formatting, Params}, State) ->
@@ -154,8 +158,87 @@ format_document_local(Dir, RelativePath,
 rangeformat_document(_Uri, _Document, _Range, _Options) ->
     {ok, []}.
 
--spec ontypeformat_document(binary(), map()
-                           , number(), number(), string(), formatting_options())
-                           -> {ok, [text_edit()]}.
-ontypeformat_document(_Uri, _Document, _Line, _Col, _Char, _Options) ->
-    {ok, []}.
+-spec ontypeformat_document(binary(),
+                            map(),
+                            number(),
+                            number(),
+                            string(),
+                            formatting_options()) ->
+                               {ok, [text_edit()]}.
+ontypeformat_document(_Uri, Document, Line, Col, <<".">>, _Options) ->
+  case find_matching_range(Document, Line) of
+    [] ->
+      {ok, []};
+    [MatchingRange] ->
+      {StartLine, _} = Id = els_poi:id(MatchingRange),
+      Text = els_dt_document:text(Document),
+      RangeText = els_text:range(Text, Id, {Line, Col - 1}),
+      % Skip formatting if the . is on a commented line.
+      case string:trim(
+             els_text:line(Text, Line - 1), both)
+      of
+        <<"%", _/binary>> ->
+          {ok, []};
+        _ ->
+          ParseF =
+            fun(Dir) ->
+               TmpFile = tmp_file(Dir),
+               ok = file:write_file(TmpFile, <<RangeText/binary, ".">>),
+               Opts =
+                 #{formatter => default_formatter,
+                   paper => 100,
+                   parse_macro_definitions => false,
+                   truncate_strings => true,
+                   parenthesize_infix_operations => true,
+                   break_indent => 2,
+                   output_dir => current},
+               RebarState = #{},
+               T = rebar3_formatter:new(default_formatter, Opts, RebarState),
+               rebar3_formatter:format_file(TmpFile, T),
+               {ok, Bin} = file:read_file(TmpFile),
+               Bin
+            end,
+          %% rebar3_formatter adds a newline, since we terminate on .
+          %% We want to leave the cursor at the current char rather
+          %% than jumping to a newline
+          NewText =
+            string:trim(
+              tempdir:mktmp(ParseF), trailing, "\n"),
+          {ok,
+           [#{range =>
+                #{start => #{line => StartLine - 1, character => 0},
+                  'end' => #{line => Line - 1, character => Col}},
+              newText => NewText}]}
+      end
+  end;
+ontypeformat_document(_Uri, _Document, _Line, _Col, Char, _Options) ->
+  ?LOG_INFO("Got unhandled character in ontypeformat_document. No formatter "
+            "configured for char: ~p",
+            [Char]),
+  {ok, []}.
+
+-spec find_foldable_ranges(els_dt_document:item()) -> [poi()].
+find_foldable_ranges(Document) ->
+  Pois = els_dt_document:pois(Document),
+  lists:filter(fun (#{kind := folding_range}) ->
+                     true;
+                   (_) ->
+                     false
+               end,
+               Pois).
+
+-spec find_matching_range(els_dt_document:item(), number()) -> [poi()].
+find_matching_range(Document, Line) ->
+  lists:filter(fun(#{range := #{from := {FromLine, _}, to := {ToLine, _}}}) ->
+                  Line >= FromLine andalso Line =< ToLine
+               end,
+               find_foldable_ranges(Document)).
+
+-spec tmp_file(string()) -> any().
+tmp_file(Dir) ->
+  Unique = erlang:unique_integer([positive]),
+  {A, B, C} = os:timestamp(),
+  N = node(),
+  filename:join(Dir,
+                lists:flatten(
+                  io_lib:format("~p-~p.~p.~p.~p", [N, A, B, C, Unique]))).

apps/els_lsp/src/els_general_provider.erl

@@ -157,6 +157,8 @@ server_capabilities() ->
             els_formatting_provider:is_enabled_document()
         , documentRangeFormattingProvider =>
             els_formatting_provider:is_enabled_range()
+        , documentOnTypeFormattingProvider =>
+            els_formatting_provider:is_enabled_on_type()
         , foldingRangeProvider =>
             els_folding_range_provider:is_enabled()
         , implementationProvider =>

apps/els_lsp/src/els_poi.erl

@@ -10,6 +10,7 @@
 
 -export([ match_pos/2
         , sort/1
+        , id/1
         ]).
 
 %%==============================================================================
@@ -42,6 +43,10 @@ match_pos(POIs, Pos) ->
                       , to   := To
                       }} = POI <- POIs, (From =< Pos) andalso (Pos =< To)].
 
+-spec id(poi()) -> poi_id().
+id(#{id := Id}) ->
+  Id.
+
 %% @doc Sorts pois based on their range
 %%
 %% Order is defined using els_range:compare/2.

rebar.config

@@ -11,7 +11,7 @@
        , {yamerl,        "0.8.1"}
        , {docsh,         "0.7.2"}
        , {elvis_core,    "~> 1.3"}
-       , {rebar3_format, "0.8.2"}
+       , {rebar3_format, "1.0.1"}
        %%, {erlfmt,        "1.0.0"}
        , {erlfmt, {git, "https://github.com/gomoripeti/erlfmt.git", {tag, "erlang_ls_parser_error_loc"}}} %% Temp until erlfmt PR 325 is merged (commit d4422d1)
        , {ephemeral,     "2.0.4"}

rebar.lock

@@ -13,10 +13,10 @@
        {ref,"e93db1c6725760def005c69d72f53b1a889b4c2f"}},
   0},
  {<<"jsx">>,{pkg,<<"jsx">>,<<"3.0.0">>},0},
- {<<"katana_code">>,{pkg,<<"katana_code">>,<<"0.2.1">>},1},
+ {<<"katana_code">>,{pkg,<<"katana_code">>,<<"1.1.2">>},1},
  {<<"providers">>,{pkg,<<"providers">>,<<"1.8.1">>},1},
  {<<"quickrand">>,{pkg,<<"quickrand">>,<<"2.0.1">>},1},
- {<<"rebar3_format">>,{pkg,<<"rebar3_format">>,<<"0.8.2">>},0},
+ {<<"rebar3_format">>,{pkg,<<"rebar3_format">>,<<"1.0.1">>},0},
  {<<"redbug">>,{pkg,<<"redbug">>,<<"2.0.6">>},0},
  {<<"tdiff">>,{pkg,<<"tdiff">>,<<"0.1.2">>},0},
  {<<"uuid">>,{pkg,<<"uuid_erl">>,<<"2.0.1">>},0},
@@ -30,10 +30,10 @@
  {<<"ephemeral">>, <<"B3E57886ADD5D90C82FE3880F5954978222A122CB8BAA123667401BBAAEC51D6">>},
  {<<"getopt">>, <<"C73A9FA687B217F2FF79F68A3B637711BB1936E712B521D8CE466B29CBF7808A">>},
  {<<"jsx">>, <<"20A170ABD4335FC6DB24D5FAD1E5D677C55DADF83D1B20A8A33B5FE159892A39">>},
- {<<"katana_code">>, <<"B2195859DF57D8BEBF619A9FD3327CD7D01563A98417156D0F4C5FAB435F2630">>},
+ {<<"katana_code">>, <<"4336743263236C3213FF1B979ECAE263940B9084ACE90E9434838F3F98CCA578">>},
  {<<"providers">>, <<"70B4197869514344A8A60E2B2A4EF41CA03DEF43CFB1712ECF076A0F3C62F083">>},
  {<<"quickrand">>, <<"6D861FA11E6EB51BB2343A2616EFF704C2681A9997F41ABC78E58FA76DA33981">>},
- {<<"rebar3_format">>, <<"2D64DA61E0B87FCA6C4512ADA6D9CBC2B27ADC9AE6844178561147E7121761BD">>},
+ {<<"rebar3_format">>, <<"F8D275C9BD9A2541880D03071AF75FD6B78FC80D74158DC0A2C48A913B03D9F4">>},
  {<<"redbug">>, <<"A764690B012B67C404562F9C6E1BA47A73892EE17DF5C15F670B1A5BF9D2F25A">>},
  {<<"tdiff">>, <<"4E1B30321F1B3D600DF65CD60858EDE1235FE4E5EE042110AB5AD90CD6464AC5">>},
  {<<"uuid">>, <<"1FD9079C544D521063897887A1C5B3302DCA98F9BB06AADCDC6FB0663F256797">>},
@@ -46,10 +46,10 @@
  {<<"ephemeral">>, <<"4B293D80F75F9C4575FF4B9C8E889A56802F40B018BF57E74F19644EFEE6C850">>},
  {<<"getopt">>, <<"53E1AB83B9CEB65C9672D3E7A35B8092E9BDC9B3EE80721471A161C10C59959C">>},
  {<<"jsx">>, <<"37BECA0435F5CA8A2F45F76A46211E76418FBEF80C36F0361C249FC75059DC6D">>},
- {<<"katana_code">>, <<"8448AD3F56D9814F98A28BE650F7191BDD506575E345CC16D586660B10F6E992">>},
+ {<<"katana_code">>, <<"E7E6162A44E826A03F68B503B7D92981B894BF834C1EF0E647783F7D6688021C">>},
  {<<"providers">>, <<"E45745ADE9C476A9A469EA0840E418AB19360DC44F01A233304E118A44486BA0">>},
  {<<"quickrand">>, <<"14DB67D4AEF6B8815810EC9F3CCEF5E324B73B56CAE3687F99D752B85BDD4C96">>},
- {<<"rebar3_format">>, <<"CA8FF27638C2169593D1449DACBE8895634193ED3334E906B54FC97F081F5213">>},
+ {<<"rebar3_format">>, <<"3896FA8BCA201C8A6B725D5DE67E0031F00A087C4BE69B4202CA7EA7AA0DA9E3">>},
  {<<"redbug">>, <<"AAD9498671F4AB91EACA5099FE85A61618158A636E6286892C4F7CF4AF171D04">>},
  {<<"tdiff">>, <<"E0C2E168F99252A5889768D5C8F1E6510A184592D4CFA06B22778A18D33D7875">>},
  {<<"uuid">>, <<"AB57CACCD51F170011E5F444CE865F84B41605E483A9EFCC468C1AFAEC87553B">>},