From 2d297441fc6100e8166f4c40c55ba2e3be8a0159 Mon Sep 17 00:00:00 2001
From: Michael Davis <mcarsondavis@gmail.com>
Date: Thu, 28 Apr 2022 08:31:38 -0500
Subject: [PATCH] [#772] Only complete arguments for snippets. (#1263)

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 fba81b286..7dbb82368 100644
--- a/apps/els_lsp/src/els_completion_provider.erl
+++ b/apps/els_lsp/src/els_completion_provider.erl
@@ -677,10 +677,16 @@ 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)
@@ -699,10 +705,16 @@ 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
    }.
 
@@ -712,29 +724,30 @@ 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() ->