feat: document symbols (#69)

Closes #41

lib/next_ls.ex

@@ -20,6 +20,7 @@ defmodule NextLS do
   alias GenLSP.Requests.{
     Initialize,
     Shutdown,
+    TextDocumentDocumentSymbol,
     TextDocumentFormatting,
     WorkspaceSymbol
   }
@@ -28,21 +29,21 @@ defmodule NextLS do
     DidOpenTextDocumentParams,
     InitializeParams,
     InitializeResult,
+    Location,
     Position,
     Range,
-    Location,
     SaveOptions,
     ServerCapabilities,
+    SymbolInformation,
     TextDocumentItem,
     TextDocumentSyncOptions,
     TextEdit,
     WorkDoneProgressBegin,
-    WorkDoneProgressEnd,
-    SymbolInformation
+    WorkDoneProgressEnd
   }
 
-  alias NextLS.Runtime
   alias NextLS.DiagnosticCache
+  alias NextLS.Runtime
   alias NextLS.SymbolTable
 
   def start_link(args) do
@@ -85,10 +86,7 @@ defmodule NextLS do
   end
 
   @impl true
-  def handle_request(
-        %Initialize{params: %InitializeParams{root_uri: root_uri}},
-        lsp
-      ) do
+  def handle_request(%Initialize{params: %InitializeParams{root_uri: root_uri}}, lsp) do
     {:reply,
      %InitializeResult{
        capabilities: %ServerCapabilities{
@@ -98,12 +96,28 @@ defmodule NextLS do
            change: TextDocumentSyncKind.full()
          },
          document_formatting_provider: true,
-         workspace_symbol_provider: true
+         workspace_symbol_provider: true,
+         document_symbol_provider: true
        },
        server_info: %{name: "NextLS"}
      }, assign(lsp, root_uri: root_uri)}
   end
 
+  def handle_request(%TextDocumentDocumentSymbol{params: %{text_document: %{uri: uri}}}, lsp) do
+    symbols =
+      try do
+        lsp.assigns.documents[uri]
+        |> Enum.join("\n")
+        |> NextLS.DocumentSymbol.fetch()
+      rescue
+        e ->
+          GenLSP.error(lsp, Exception.format_banner(:error, e, __STACKTRACE__))
+          nil
+      end
+
+    {:reply, symbols, lsp}
+  end
+
   def handle_request(%WorkspaceSymbol{params: %{query: query}}, lsp) do
     filter = fn sym ->
       if query == "" do

lib/next_ls/document_symbol.ex

@@ -0,0 +1,222 @@
+defmodule NextLS.DocumentSymbol do
+  alias GenLSP.Structures.{
+    Position,
+    Range,
+    DocumentSymbol
+  }
+
+  # we set the literal encoder so that we can know when atoms and strings start and end
+  # this makes it useful for knowing the exact locations of struct field definitions
+  @spec fetch(text :: String.t()) :: list(DocumentSymbol.t())
+  def fetch(text) do
+    text
+    |> Code.string_to_quoted!(
+      literal_encoder: fn literal, meta ->
+        if is_atom(literal) or is_binary(literal) do
+          {:ok, {:__literal__, meta, [literal]}}
+        else
+          {:ok, literal}
+        end
+      end,
+      unescape: false,
+      token_metadata: true,
+      columns: true
+    )
+    |> walker(nil)
+    |> List.wrap()
+  end
+
+  defp walker([{{:__literal__, _, [:do]}, {_, _, _exprs} = ast}], mod) do
+    walker(ast, mod)
+  end
+
+  defp walker({:__block__, _, exprs}, mod) do
+    for expr <- exprs, sym = walker(expr, mod), sym != nil do
+      sym
+    end
+  end
+
+  defp walker({:defmodule, meta, [name | children]}, _mod) do
+    name = Macro.to_string(unliteral(name))
+
+    %DocumentSymbol{
+      name: name,
+      kind: GenLSP.Enumerations.SymbolKind.module(),
+      children: List.flatten(for(child <- children, sym = walker(child, name), sym != nil, do: sym)),
+      range: %Range{
+        start: %Position{line: meta[:line] - 1, character: meta[:column] - 1},
+        end: %Position{line: meta[:end][:line] - 1, character: meta[:end][:column] - 1}
+      },
+      selection_range: %Range{
+        start: %Position{line: meta[:line] - 1, character: meta[:column] - 1},
+        end: %Position{line: meta[:line] - 1, character: meta[:column] - 1}
+      }
+    }
+  end
+
+  defp walker({:describe, meta, [name | children]}, mod) do
+    name = ("describe " <> Macro.to_string(unliteral(name))) |> String.replace("\n", "")
+
+    %DocumentSymbol{
+      name: name,
+      kind: GenLSP.Enumerations.SymbolKind.class(),
+      children: List.flatten(for(child <- children, sym = walker(child, mod), sym != nil, do: sym)),
+      range: %Range{
+        start: %Position{line: meta[:line] - 1, character: meta[:column] - 1},
+        end: %Position{line: meta[:end][:line] - 1, character: meta[:end][:column] - 1}
+      },
+      selection_range: %Range{
+        start: %Position{line: meta[:line] - 1, character: meta[:column] - 1},
+        end: %Position{line: meta[:line] - 1, character: meta[:column] - 1}
+      }
+    }
+  end
+
+  defp walker({:defstruct, meta, [fields]}, mod) do
+    fields =
+      for field <- fields do
+        {name, start_line, start_column} =
+          case field do
+            {:__literal__, meta, [name]} ->
+              start_line = meta[:line] - 1
+              start_column = meta[:column] - 1
+              name = Macro.to_string(name)
+
+              {name, start_line, start_column}
+
+            {{:__literal__, meta, [name]}, default} ->
+              start_line = meta[:line] - 1
+              start_column = meta[:column] - 1
+              name = to_string(name) <> ": " <> Macro.to_string(unliteral(default))
+
+              {name, start_line, start_column}
+          end
+
+        %DocumentSymbol{
+          name: name,
+          children: [],
+          kind: GenLSP.Enumerations.SymbolKind.field(),
+          range: %Range{
+            start: %Position{
+              line: start_line,
+              character: start_column
+            },
+            end: %Position{
+              line: start_line,
+              character: start_column + String.length(name)
+            }
+          },
+          selection_range: %Range{
+            start: %Position{line: start_line, character: start_column},
+            end: %Position{line: start_line, character: start_column}
+          }
+        }
+      end
+
+    %DocumentSymbol{
+      name: "%#{mod}{}",
+      children: fields,
+      kind: elixir_kind_to_lsp_kind(:defstruct),
+      range: %Range{
+        start: %Position{
+          line: meta[:line] - 1,
+          character: meta[:column] - 1
+        },
+        end: %Position{
+          line: meta[:end_of_expression][:line] - 1,
+          character: meta[:end_of_expression][:column] - 1
+        }
+      },
+      selection_range: %Range{
+        start: %Position{line: meta[:line] - 1, character: meta[:column] - 1},
+        end: %Position{line: meta[:line] - 1, character: meta[:column] - 1}
+      }
+    }
+  end
+
+  defp walker({:@, meta, [{_name, _, value}]} = attribute, _) when length(value) > 0 do
+    %DocumentSymbol{
+      name: attribute |> unliteral() |> Macro.to_string() |> String.replace("\n", ""),
+      children: [],
+      kind: elixir_kind_to_lsp_kind(:@),
+      range: %Range{
+        start: %Position{
+          line: meta[:line] - 1,
+          character: meta[:column] - 1
+        },
+        end: %Position{
+          line: (meta[:end_of_expression] || meta)[:line] - 1,
+          character: (meta[:end_of_expression] || meta)[:column] - 1
+        }
+      },
+      selection_range: %Range{
+        start: %Position{line: meta[:line] - 1, character: meta[:column] - 1},
+        end: %Position{line: meta[:line] - 1, character: meta[:column] - 1}
+      }
+    }
+  end
+
+  defp walker({type, meta, [name | _children]}, _) when type in [:test, :feature, :property] do
+    %DocumentSymbol{
+      name: "#{type} #{Macro.to_string(unliteral(name))}" |> String.replace("\n", ""),
+      children: [],
+      kind: GenLSP.Enumerations.SymbolKind.constructor(),
+      range: %Range{
+        start: %Position{
+          line: meta[:line] - 1,
+          character: meta[:column] - 1
+        },
+        end: %Position{
+          line: (meta[:end] || meta[:end_of_expression] || meta)[:line] - 1,
+          character: (meta[:end] || meta[:end_of_expression] || meta)[:column] - 1
+        }
+      },
+      selection_range: %Range{
+        start: %Position{line: meta[:line] - 1, character: meta[:column] - 1},
+        end: %Position{line: meta[:line] - 1, character: meta[:column] - 1}
+      }
+    }
+  end
+
+  defp walker({type, meta, [name | _children]}, _) when type in [:def, :defp, :defmacro, :defmacro] do
+    %DocumentSymbol{
+      name: "#{type} #{name |> unliteral() |> Macro.to_string()}" |> String.replace("\n", ""),
+      children: [],
+      kind: elixir_kind_to_lsp_kind(type),
+      range: %Range{
+        start: %Position{
+          line: meta[:line] - 1,
+          character: meta[:column] - 1
+        },
+        end: %Position{
+          line: (meta[:end] || meta[:end_of_expression] || meta)[:line] - 1,
+          character: (meta[:end] || meta[:end_of_expression] || meta)[:column] - 1
+        }
+      },
+      selection_range: %Range{
+        start: %Position{line: meta[:line] - 1, character: meta[:column] - 1},
+        end: %Position{line: meta[:line] - 1, character: meta[:column] - 1}
+      }
+    }
+  end
+
+  defp walker(_ast, _) do
+    nil
+  end
+
+  defp unliteral(ast) do
+    Macro.prewalk(ast, fn
+      {:__literal__, _, [literal]} ->
+        literal
+
+      node ->
+        node
+    end)
+  end
+
+  defp elixir_kind_to_lsp_kind(:defstruct), do: GenLSP.Enumerations.SymbolKind.struct()
+  defp elixir_kind_to_lsp_kind(:@), do: GenLSP.Enumerations.SymbolKind.property()
+
+  defp elixir_kind_to_lsp_kind(kind) when kind in [:def, :defp, :defmacro, :defmacrop, :test, :describe],
+    do: GenLSP.Enumerations.SymbolKind.function()
+end

lib/next_ls/symbol_table.ex

@@ -5,6 +5,16 @@ defmodule NextLS.SymbolTable do
   defmodule Symbol do
     defstruct [:file, :module, :type, :name, :line, :col]
 
+    @type t :: %__MODULE__{
+            file: String.t(),
+            module: module(),
+            type: atom(),
+            name: atom(),
+            line: integer(),
+            col: integer()
+          }
+
+    @spec new(keyword()) :: t()
     def new(args) do
       struct(__MODULE__, args)
     end
@@ -20,6 +30,10 @@ defmodule NextLS.SymbolTable do
   @spec symbols(pid() | atom()) :: list(struct())
   def symbols(server), do: GenServer.call(server, :symbols)
 
+  @spec symbols(pid() | atom(), String.t()) :: list(struct())
+  def symbols(server, file), do: GenServer.call(server, {:symbols, file})
+
+  @spec close(pid() | atom()) :: :ok | {:error, term()}
   def close(server), do: GenServer.call(server, :close)
 
   def init(args) do
@@ -36,10 +50,26 @@ defmodule NextLS.SymbolTable do
     {:ok, %{table: name}}
   end
 
+  def handle_call({:symbols, file}, _, state) do
+    symbols =
+      case :dets.lookup(state.table, file) do
+        [{_, symbols} | _rest] -> symbols
+        _ -> []
+      end
+
+    {:reply, symbols, state}
+  end
+
   def handle_call(:symbols, _, state) do
     symbols =
       :dets.foldl(
-        fn {_key, symbol}, acc -> [symbol | acc] end,
+        fn {_key, symbol}, acc ->
+          if String.match?(to_string(symbol.name), ~r/__.*__/) do
+            acc
+          else
+            [symbol | acc]
+          end
+        end,
         [],
         state.table
       )
@@ -63,6 +93,7 @@ defmodule NextLS.SymbolTable do
     } = symbols
 
     :dets.delete(state.table, mod)
+    :dets.delete(state.table, file)
 
     :dets.insert(
       state.table,
@@ -94,9 +125,7 @@ defmodule NextLS.SymbolTable do
       )
     end
 
-    for {name, {:v1, type, _meta, clauses}} <- defs,
-        not String.match?(to_string(name), ~r/__.*__/),
-        {meta, _, _, _} <- clauses do
+    for {name, {:v1, type, _meta, clauses}} <- defs, {meta, _, _, _} <- clauses do
       :dets.insert(
         state.table,
         {mod,