From 51c0c37d128ec487de6bf2ca47ee5f7b8162eab0 Mon Sep 17 00:00:00 2001
From: Michael Davis <mcarsondavis@gmail.com>
Date: Fri, 8 Apr 2022 21:35:24 -0500
Subject: [PATCH] [#772] Only complete arguments for snippets.

This commit prevents the completion provider from providing arguments
for functions/macros when an editor does not enable snippets. With
snippet support, arguments are useful because they can be tabbed between,
but for an editor which does not implement snippets, the generated
arguments are mostly a hassle: you have to move back to replace the
arguments.
---
 apps/els_lsp/src/els_completion_provider.erl | 51 ++++++++++++--------
 1 file changed, 32 insertions(+), 19 deletions(-)

diff --git a/apps/els_lsp/src/els_completion_provider.erl b/apps/els_lsp/src/els_completion_provider.erl
index e8d8fec9b..c3e5ba08b 100644
--- a/apps/els_lsp/src/els_completion_provider.erl
+++ b/apps/els_lsp/src/els_completion_provider.erl
@@ -695,10 +695,16 @@ completion_item(#{kind := Kind, id := {F, A}, data := POIData}, Data, false)
        Kind =:= type_definition ->
   ArgsNames = maps:get(args, POIData),
   Label = io_lib:format("~p/~p", [F, A]),
+  SnippetSupport = snippet_support(),
+  Format =
+    case SnippetSupport of
+      true -> ?INSERT_TEXT_FORMAT_SNIPPET;
+      false -> ?INSERT_TEXT_FORMAT_PLAIN_TEXT
+    end,
   #{ label            => els_utils:to_binary(Label)
    , kind             => completion_item_kind(Kind)
-   , insertText       => snippet_function(F, ArgsNames)
-   , insertTextFormat => ?INSERT_TEXT_FORMAT_SNIPPET
+   , insertText       => format_function(F, ArgsNames, SnippetSupport)
+   , insertTextFormat => Format
    , data             => Data
    };
 completion_item(#{kind := Kind, id := {F, A}}, Data, true)
@@ -717,10 +723,16 @@ completion_item(#{kind := Kind = record, id := Name}, Data, _) ->
    };
 completion_item(#{kind := Kind = define, id := Name, data := Info}, Data, _) ->
   #{args := ArgNames} = Info,
+  SnippetSupport = snippet_support(),
+  Format =
+    case SnippetSupport of
+      true -> ?INSERT_TEXT_FORMAT_SNIPPET;
+      false -> ?INSERT_TEXT_FORMAT_PLAIN_TEXT
+    end,
   #{ label            => macro_label(Name)
    , kind             => completion_item_kind(Kind)
-   , insertText       => snippet_macro(Name, ArgNames)
-   , insertTextFormat => ?INSERT_TEXT_FORMAT_SNIPPET
+   , insertText       => format_macro(Name, ArgNames, SnippetSupport)
+   , insertTextFormat => Format
    , data             => Data
    }.
 
@@ -730,29 +742,30 @@ macro_label({Name, Arity}) ->
 macro_label(Name) ->
   atom_to_binary(Name, utf8).
 
--spec snippet_function(atom(), [{integer(), string()}]) -> binary().
-snippet_function(Name, Args) ->
-  snippet_args(atom_to_label(Name), Args).
+-spec format_function(atom(), [{integer(), string()}], boolean()) -> binary().
+format_function(Name, Args, SnippetSupport) ->
+  format_args(atom_to_label(Name), Args, SnippetSupport).
 
--spec snippet_macro( atom() | {atom(), non_neg_integer()}
-                   , [{integer(), string()}]) -> binary().
-snippet_macro({Name0, _Arity}, Args) ->
+-spec format_macro( atom() | {atom(), non_neg_integer()}
+                   , [{integer(), string()}]
+                   , boolean()) -> binary().
+format_macro({Name0, _Arity}, Args, SnippetSupport) ->
   Name = atom_to_binary(Name0, utf8),
-  snippet_args(Name, Args);
-snippet_macro(Name, none) ->
+  format_args(Name, Args, SnippetSupport);
+format_macro(Name, none, _SnippetSupport) ->
   atom_to_binary(Name, utf8).
 
--spec snippet_args(binary(), [{integer(), string()}]) -> binary().
-snippet_args(Name, Args0) ->
+-spec format_args(binary(), [{integer(), string()}], boolean()) -> binary().
+format_args(Name, Args0, SnippetSupport) ->
   Args =
-    case snippet_support() of
+    case SnippetSupport of
       false ->
-        [A || {_N, A} <- Args0];
+        [];
       true ->
-        [["${", integer_to_list(N), ":", A, "}"] || {N, A} <- Args0]
+        ArgList = [["${", integer_to_list(N), ":", A, "}"] || {N, A} <- Args0],
+        ["(", string:join(ArgList, ", "), ")"]
     end,
-  Snippet = [Name, "(", string:join(Args, ", "), ")"],
-  els_utils:to_binary(Snippet).
+  els_utils:to_binary([Name | Args]).
 
 -spec snippet_support() -> boolean().
 snippet_support() ->