feat(completions): local variables (#393)

Working towards #45

lib/next_ls.ex

@@ -624,8 +624,6 @@ defmodule NextLS do
       end)
       |> Enum.reverse()
 
-    dbg(results)
-
     {:reply, results, lsp}
   rescue
     e ->

lib/next_ls/autocomplete.ex

@@ -24,14 +24,14 @@ defmodule NextLS.Autocomplete do
   @alias_only_atoms ~w(alias import require)a
   @alias_only_charlists ~w(alias import require)c
 
-  def expand(code, runtime) do
+  def expand(code, runtime, env) do
     case path_fragment(code) do
-      [] -> expand_code(code, runtime)
+      [] -> expand_code(code, runtime, env)
       path -> expand_path(path)
     end
   end
 
-  defp expand_code(code, runtime) do
+  defp expand_code(code, runtime, env) do
     code = Enum.reverse(code)
     # helper = get_helper(code)
 
@@ -62,13 +62,13 @@ defmodule NextLS.Autocomplete do
         expand_dot_call(path, List.to_atom(hint), runtime)
 
       :expr ->
-        expand_container_context(code, :expr, "", runtime) || expand_local_or_var("", "", runtime)
+        expand_container_context(code, :expr, "", runtime) || expand_local_or_var(code, "", runtime, env)
 
       {:local_or_var, local_or_var} ->
         hint = List.to_string(local_or_var)
 
         expand_container_context(code, :expr, hint, runtime) ||
-          expand_local_or_var(hint, List.to_string(local_or_var), runtime)
+          expand_local_or_var(hint, List.to_string(local_or_var), runtime, env)
 
       {:local_arity, local} ->
         expand_local(List.to_string(local), true, runtime)
@@ -77,7 +77,7 @@ defmodule NextLS.Autocomplete do
         expand_aliases("", runtime)
 
       {:local_call, local} ->
-        expand_local_call(List.to_atom(local), runtime)
+        expand_local_call(List.to_atom(local), runtime, env)
 
       {:operator, operator} when operator in ~w(:: -)c ->
         expand_container_context(code, :operator, "", runtime) ||
@@ -90,10 +90,10 @@ defmodule NextLS.Autocomplete do
         expand_local(List.to_string(operator), true, runtime)
 
       {:operator_call, operator} when operator in ~w(|)c ->
-        expand_container_context(code, :expr, "", runtime) || expand_local_or_var("", "", runtime)
+        expand_container_context(code, :expr, "", runtime) || expand_local_or_var("", "", runtime, env)
 
       {:operator_call, _operator} ->
-        expand_local_or_var("", "", runtime)
+        expand_local_or_var("", "", runtime, env)
 
       {:sigil, []} ->
         expand_sigil(runtime)
@@ -163,12 +163,12 @@ defmodule NextLS.Autocomplete do
 
   ## Expand call
 
-  defp expand_local_call(fun, runtime) do
+  defp expand_local_call(fun, runtime, env) do
     runtime
     |> imports_from_env()
     |> Enum.filter(fn {_, funs} -> List.keymember?(funs, fun, 0) end)
     |> Enum.flat_map(fn {module, _} -> get_signatures(fun, module) end)
-    |> expand_signatures(runtime)
+    |> expand_signatures(runtime, env)
   end
 
   defp expand_dot_call(path, fun, runtime) do
@@ -192,7 +192,7 @@ defmodule NextLS.Autocomplete do
     yes([head])
   end
 
-  defp expand_signatures([], runtime), do: expand_local_or_var("", "", runtime)
+  defp expand_signatures([], runtime, env), do: expand_local_or_var("", "", runtime, env)
 
   ## Expand dot
 
@@ -259,8 +259,8 @@ defmodule NextLS.Autocomplete do
 
   ## Expand local or var
 
-  defp expand_local_or_var(code, hint, runtime) do
-    format_expansion(match_var(code, hint, runtime) ++ match_local(code, false, runtime))
+  defp expand_local_or_var(code, hint, runtime, env) do
+    format_expansion(match_var(code, hint, runtime, env) ++ match_local(hint, false, runtime))
   end
 
   defp expand_local(hint, exact?, runtime) do
@@ -286,9 +286,9 @@ defmodule NextLS.Autocomplete do
       match_module_funs(runtime, nil, imports, hint, exact?)
   end
 
-  defp match_var(code, hint, runtime) do
+  defp match_var(code, hint, _runtime, env) do
     code
-    |> variables_from_binding(runtime)
+    |> variables_from_binding(env)
     |> Enum.filter(&String.starts_with?(&1, hint))
     |> Enum.sort()
     |> Enum.map(&%{kind: :variable, name: &1})
@@ -774,13 +774,8 @@ defmodule NextLS.Autocomplete do
     []
   end
 
-  defp variables_from_binding(_hint, _runtime) do
-    # {:ok, ast} = Code.Fragment.container_cursor_to_quoted(hint, columns: true)
-
-    # ast |> Macro.to_string() |> IO.puts()
-
-    # NextLS.ASTHelpers.Variables.collect(ast)
-    []
+  defp variables_from_binding(_hint, env) do
+    env.variables
   end
 
   defp value_from_binding([_var | _path], _runtime) do

lib/next_ls/helpers/ast_helpers/env.ex

@@ -0,0 +1,134 @@
+defmodule NextLS.ASTHelpers.Env do
+  @moduledoc false
+  alias Sourceror.Zipper
+
+  defp inside?(range, position) do
+    Sourceror.compare_positions(range.start, position) == :lt && Sourceror.compare_positions(range.end, position) == :gt
+  end
+
+  def build(ast) do
+    cursor =
+      ast
+      |> Zipper.zip()
+      |> Zipper.find(fn
+        {:__cursor__, _, _} -> true
+        _ -> false
+      end)
+
+    position = cursor |> Zipper.node() |> Sourceror.get_range() |> Map.get(:start)
+    zipper = Zipper.prev(cursor)
+
+    env =
+      ascend(zipper, %{variables: []}, fn node, zipper, acc ->
+        is_inside =
+          with {_, _, _} <- node,
+               range when not is_nil(range) <- Sourceror.get_range(node) do
+            inside?(range, position)
+          else
+            _ ->
+              false
+          end
+
+        case node do
+          {match_op, _, [pm | _]} when match_op in [:=] and not is_inside ->
+            {_, vars} =
+              Macro.prewalk(pm, [], fn node, acc ->
+                case node do
+                  {name, _, nil} ->
+                    {node, [to_string(name) | acc]}
+
+                  _ ->
+                    {node, acc}
+                end
+              end)
+
+            Map.update!(acc, :variables, &(vars ++ &1))
+
+          {match_op, _, [pm | _]} when match_op in [:<-] ->
+            up_node = zipper |> Zipper.up() |> Zipper.node()
+
+            # in_match operator comes with for and with normally, so we need to 
+            # check if we are inside the parent node, which is the for/with
+            is_inside =
+              with {_, _, _} <- up_node,
+                   range when not is_nil(range) <- Sourceror.get_range(up_node) do
+                inside?(range, position)
+              else
+                _ ->
+                  false
+              end
+
+            if is_inside do
+              {_, vars} =
+                Macro.prewalk(pm, [], fn node, acc ->
+                  case node do
+                    {name, _, nil} ->
+                      {node, [to_string(name) | acc]}
+
+                    _ ->
+                      {node, acc}
+                  end
+                end)
+
+              Map.update!(acc, :variables, &(vars ++ &1))
+            else
+              acc
+            end
+
+          {def, _, [{_, _, args} | _]} when def in [:def, :defp, :defmacro, :defmacrop] and args != [] and is_inside ->
+            {_, vars} =
+              Macro.prewalk(args, [], fn node, acc ->
+                case node do
+                  {name, _, nil} ->
+                    {node, [to_string(name) | acc]}
+
+                  _ ->
+                    {node, acc}
+                end
+              end)
+
+            Map.update!(acc, :variables, &(vars ++ &1))
+
+          {:->, _, [args | _]} when args != [] ->
+            {_, vars} =
+              Macro.prewalk(args, [], fn node, acc ->
+                case node do
+                  {name, _, nil} ->
+                    {node, [to_string(name) | acc]}
+
+                  _ ->
+                    {node, acc}
+                end
+              end)
+
+            Map.update!(acc, :variables, &(vars ++ &1))
+
+          _ ->
+            acc
+        end
+      end)
+
+    %{
+      variables: Enum.uniq(env.variables)
+    }
+  end
+
+  def ascend(%Zipper{path: nil} = zipper, acc, callback), do: callback.(Zipper.node(zipper), zipper, acc)
+
+  def ascend(zipper, acc, callback) do
+    node = Zipper.node(zipper)
+    acc = callback.(node, zipper, acc)
+
+    zipper =
+      cond do
+        match?({:->, _, _}, node) ->
+          Zipper.up(zipper)
+
+        true ->
+          left = Zipper.left(zipper)
+          if left, do: left, else: Zipper.up(zipper)
+      end
+
+    ascend(zipper, acc, callback)
+  end
+end

test/next_ls/autocomplete_test.exs

@@ -81,8 +81,8 @@ defmodule NextLS.AutocompleteTest do
     [runtime: pid]
   end
 
-  defp expand(runtime, expr) do
-    NextLS.Autocomplete.expand(Enum.reverse(expr), runtime)
+  defp expand(runtime, expr, env \\ %{variables: []}) do
+    NextLS.Autocomplete.expand(Enum.reverse(expr), runtime, env)
   end
 
   test "Erlang module completion", %{runtime: runtime} do
@@ -414,14 +414,42 @@ defmodule NextLS.AutocompleteTest do
             ]} = expand(runtime, ~c"put_")
   end
 
-  # TODO: this only partially works, will not say we support for now
-  # test "variable name completion", %{runtime: runtime} do
-  #   prev = "numeral = 3; number = 3; nothing = nil"
-  #   assert expand(runtime, ~c"#{prev}\nnumb") == {:yes, ~c"er", []}
-  #   assert expand(runtime, ~c"#{prev}\nnum") == {:yes, ~c"", [~c"number", ~c"numeral"]}
-  #   # FIXME: variables + local functions
-  #   # assert expand(runtime, ~c"#{prev}\nno") == {:yes, ~c"", [~c"nothing", ~c"node/0", ~c"node/1", ~c"not/1"]}
-  # end
+  test "variable name completion", %{runtime: runtime} do
+    prev = "numeral = 3; number = 3; nothing = nil"
+    env = %{variables: ["numeral", "number", "nothing"]}
+    assert expand(runtime, ~c"#{prev}\nnumb", env) == {:yes, [%{name: "number", kind: :variable}]}
+
+    assert expand(runtime, ~c"#{prev}\nnum", env) ==
+             {:yes, [%{name: "number", kind: :variable}, %{name: "numeral", kind: :variable}]}
+
+    assert expand(runtime, ~c"#{prev}\nno", env) == {
+             :yes,
+             [
+               %{name: "nothing", kind: :variable},
+               %{
+                 arity: 0,
+                 name: "node",
+                 docs:
+                   "## Kernel.node/0\n\nReturns an atom representing the name of the local node.\nIf the node is not alive, `:nonode@nohost` is returned instead.\n\nAllowed in guard tests. Inlined by the compiler.\n\n",
+                 kind: :function
+               },
+               %{
+                 arity: 1,
+                 name: "node",
+                 docs:
+                   "## Kernel.node/1\n\nReturns an atom representing the name of the local node.\nIf the node is not alive, `:nonode@nohost` is returned instead.\n\nAllowed in guard tests. Inlined by the compiler.\n\n",
+                 kind: :function
+               },
+               %{
+                 arity: 1,
+                 name: "not",
+                 docs:
+                   "## Kernel.not/1\n\nStrictly boolean \"not\" operator.\n\n`value` must be a boolean; if it's not, an `ArgumentError` exception is raised.\n\nAllowed in guard tests. Inlined by the compiler.\n\n## Examples\n\n    iex> not false\n    true\n\n\n",
+                 kind: :function
+               }
+             ]
+           }
+  end
 
   # TODO: locals
   # test "completion of manually imported functions and macros", %{runtime: runtime} do