Add support for sessionless expression interpreters

lua/dap.lua

@@ -268,9 +268,20 @@ M.adapters = {}
 ---@type table<string, dap.Configuration[]>
 M.configurations = {}
 
+
+---@class dap.Interpreter
+---@field evaluate fun(expression: string): dap.InterpreterResult
+
+---@class dap.InterpreterResult : dap.VariableContainer
+---@field result string
+---@field type? string
+
 local providers = {
   ---@type table<string, fun(bufnr: integer): dap.Configuration[]>
   configs = {},
+
+  ---@type table<string, dap.Interpreter>
+  interpreters = {},
 }
 do
   local providers_mt = {
@@ -279,6 +290,70 @@ do
     end,
   }
   M.providers = setmetatable(providers, providers_mt)
+
+  local lua_interpreter = {}
+  providers.interpreters.lua = lua_interpreter
+
+  ---@param key any
+  ---@param value any
+  ---@return dap.Variable
+  local function to_variable(key, value)
+    local result = {
+      name = tostring(key),
+      value = tostring(value),
+      type = type(value)
+    }
+    if type(value) == "table" then
+      result.value = result.value .. " size=" .. vim.tbl_count(value)
+      result.variables = {}
+      for k, v in pairs(value) do
+        table.insert(result.variables, to_variable(k, v))
+      end
+    end
+    return result
+  end
+
+  ---@param expression string
+  ---@result dap.InterpreterResult
+  function lua_interpreter.evaluate(expression)
+    local parser = vim.treesitter.get_string_parser(expression, "lua")
+    local trees = parser:parse()
+    local root = trees[1]:root() -- root is likely chunk
+    local child = root:child(root:child_count() - 1)
+    if child and child:type() ~= "return_statement" then
+      local slnum, scol, _, _ = child:range()
+      local lines = vim.split(expression, "\n", { plain = true })
+      local line = lines[slnum + 1]
+      lines[slnum + 1] = line:sub(1, scol) .. "return " .. line:sub(scol)
+      expression = table.concat(lines, "\n")
+    end
+    local fn, err = loadstring(expression)
+    local result
+    if fn then
+      local env = getfenv(fn)
+      local newenv = {}
+      function newenv.print(...)
+        local line = table.concat({...})
+        M.repl.append(line .. "\n", nil, { newline = false })
+      end
+      setmetatable(newenv, {__index = env})
+      setfenv(fn, newenv)
+      result = fn() or "nil"
+      if type(result) == "table" then
+        local tbl = result
+        result = tostring(result) .. " size=" .. tostring(vim.tbl_count(tbl))
+        local variables = {}
+        for k, v in pairs(tbl) do
+          table.insert(variables, to_variable(k, v))
+        end
+        return {result = result, variables = variables}
+      end
+    end
+    return {
+      result = result and tostring(result) or ("Error: " .. err),
+      variables = {}
+    }
+  end
 end
 
 

lua/dap/entity.lua

@@ -6,12 +6,14 @@ local variable = {}
 M.variable = variable
 
 local syntax_mapping = {
-  boolean = 'Boolean',
-  String = 'String',
-  int = 'Number',
-  long = 'Number',
-  double = 'Float',
-  float = 'Float',
+  boolean = "Boolean",
+  String = "String",
+  int = "Number",
+  long = "Number",
+  number = "Number",
+  double = "Float",
+  float = "Float",
+  ["function"] = "Function",
 }
 
 
@@ -35,7 +37,7 @@ function variable.render_parent(var)
   if var.name then
     return variable.render_child(var --[[@as dap.Variable]], 0)
   end
-  local syntax_group = var.type and syntax_mapping[var.type]
+  local syntax_group = var.type and syntax_mapping[var.type:lower()]
   if syntax_group then
     return var.result, {{syntax_group, 0, -1},}
   end
@@ -62,7 +64,7 @@ function variable.has_children(var)
   return (var.variables and #var.variables > 0) or var.variablesReference ~= 0
 end
 
----@param var dap.Variable|dap.Scope
+---@param var dap.VariableContainer
 ---@result dap.Variable[]
 function variable.get_children(var)
   return var.variables or {}
@@ -82,7 +84,7 @@ local function cmp_vars(a, b)
 end
 
 
----@param var dap.Variable|dap.Scope
+---@param var dap.VariableContainer
 ---@param cb fun(variables: dap.Variable[])
 function variable.fetch_children(var, cb)
   local session = require('dap').session()

lua/dap/health.lua

@@ -33,10 +33,10 @@ function M.check()
       health.info("Adapter is a function. Can't validate it")
     else
       if adapter.type == "executable" then
-        adapter = adapter --[[@as ExecutableAdapter]]
+        adapter = adapter --[[@as dap.ExecutableAdapter]]
         check_executable(adapter.command)
       elseif adapter.type == "server" then
-        adapter = adapter --[[@as ServerAdapter]]
+        adapter = adapter --[[@as dap.ServerAdapter]]
         if not adapter.port then
           health.error("Missing required `port` property")
         end
@@ -44,7 +44,7 @@ function M.check()
           check_executable(adapter.executable.command)
         end
       elseif adapter.type == "pipe" then
-        adapter = adapter --[[@as PipeAdapter]]
+        adapter = adapter --[[@as dap.PipeAdapter]]
         if not adapter.pipe then
           health.error("Missing required `pipe` property")
         end

lua/dap/protocol.lua

@@ -98,18 +98,23 @@
 ---@class dap.VariableResponse
 ---@field variables dap.Variable[]
 
----@class dap.Variable
+
+---@class dap.VariableContainer
+---@field variablesReference integer if > 0 the variable is structured
+---@field variables? dap.Variable[] resolved variablesReference. Not part of the spec; added by nvim-dap
+---@field parent? dap.VariableContainer injected by nvim-dap
+
+
+---@class dap.Variable : dap.VariableContainer
 ---@field name string
 ---@field value string
 ---@field type? string
 ---@field presentationHint? dap.VariablePresentationHint
 ---@field evaluateName? string
----@field variablesReference number if > 0 the variable is structured
 ---@field namedVariables? number
 ---@field indexedVariables? number
 ---@field memoryReference? string
----@field variables? dap.Variable[] resolved variablesReference. Not part of the spec; added by nvim-dap
----@field parent? dap.Variable|dap.Scope injected by nvim-dap
+
 
 ---@class dap.EvaluateArguments
 ---@field expression string
@@ -117,11 +122,11 @@
 ---@field context? "watch"|"repl"|"hover"|"clipboard"|"variables"|string
 ---@field format? dap.ValueFormat
 
----@class dap.EvaluateResponse
+
+---@class dap.EvaluateResponse : dap.VariableContainer
 ---@field result string
 ---@field type? string
 ---@field presentationHint? dap.VariablePresentationHint
----@field variablesReference number
 ---@field namedVariables? number
 ---@field indexedVariables? number
 ---@field memoryReference? string

lua/dap/repl.lua

@@ -152,6 +152,8 @@ local function print_commands()
 end
 
 
+---@param err dap.ErrorResponse?
+---@param resp dap.EvaluateResponse|dap.InterpreterResult|nil
 local function evaluate_handler(err, resp)
   if err then
     local message = utils.fmt_error(err)
@@ -160,9 +162,15 @@ local function evaluate_handler(err, resp)
     end
     return
   end
+  if not resp then
+    M.append("No response", nil, { newline = false })
+    return
+  end
   local layer = ui.layer(repl.buf)
   local attributes = (resp.presentationHint or {}).attributes or {}
-  if resp.variablesReference > 0 or vim.tbl_contains(attributes, 'rawString') then
+  local var_ref = resp.variablesReference or 0
+  local vars = resp.variables
+  if (vars and next(vars)) or var_ref > 0 or vim.tbl_contains(attributes, 'rawString') then
     local spec = require('dap.entity').variable.tree_spec
     local tree = ui.new_tree(spec)
     -- tree.render would "append" twice, once for the top element and once for the children
@@ -217,7 +225,9 @@ local function print_threads(threads)
 end
 
 
-function execute(text)
+---@param opts dap.repl.execute.opts?
+function execute(text, opts)
+  opts = opts or {}
   if text == '' then
     if history.last then
       text = history.last
@@ -252,15 +262,16 @@ function execute(text)
     end
     return
   end
-  if not session then
-    M.append('No active debug session')
-    return
-  end
+
   if vim.tbl_contains(M.commands.continue, text) then
     require('dap').continue()
   elseif vim.tbl_contains(M.commands.next_, text) then
     require('dap').step_over()
   elseif vim.tbl_contains(M.commands.capabilities, text) then
+    if not session then
+      M.append('No active debug session')
+      return
+    end
     M.append(vim.inspect(session.capabilities))
   elseif vim.tbl_contains(M.commands.into, text) then
     require('dap').step_into()
@@ -269,24 +280,48 @@ function execute(text)
   elseif vim.tbl_contains(M.commands.out, text) then
     require('dap').step_out()
   elseif vim.tbl_contains(M.commands.up, text) then
+    if not session then
+      M.append('No active debug session')
+      return
+    end
     session:_frame_delta(1)
     M.print_stackframes()
   elseif vim.tbl_contains(M.commands.step_back, text) then
     require('dap').step_back()
   elseif vim.tbl_contains(M.commands.pause, text) then
+    if not session then
+      M.append('No active debug session')
+      return
+    end
     session:_pause()
   elseif vim.tbl_contains(M.commands.reverse_continue, text) then
     require('dap').reverse_continue()
   elseif vim.tbl_contains(M.commands.down, text) then
+    if not session then
+      M.append('No active debug session')
+      return
+    end
     session:_frame_delta(-1)
     M.print_stackframes()
   elseif vim.tbl_contains(M.commands.goto_, splitted_text[1]) then
+    if not session then
+      M.append('No active debug session')
+      return
+    end
     if splitted_text[2] then
       session:_goto(tonumber(splitted_text[2]))
     end
   elseif vim.tbl_contains(M.commands.scopes, text) then
+    if not session then
+      M.append('No active debug session')
+      return
+    end
     print_scopes(session.current_frame)
   elseif vim.tbl_contains(M.commands.threads, text) then
+    if not session then
+      M.append('No active debug session')
+      return
+    end
     print_threads(vim.tbl_values(session.threads))
   elseif vim.tbl_contains(M.commands.frames, text) then
     M.print_stackframes()
@@ -294,14 +329,26 @@ function execute(text)
     local command = splitted_text[1]
     local args = string.sub(text, string.len(command)+2)
     M.commands.custom_commands[command](args)
-  else
+  elseif session then
     session:evaluate(text, evaluate_handler)
+  else
+    local dap = require("dap")
+    local interpreter = dap.providers.interpreters[opts.filetype or "lua"]
+    if interpreter then
+      local result = interpreter.evaluate(text)
+      evaluate_handler(nil, result)
+    end
   end
 end
 
 
+---@class dap.repl.execute.opts
+---@field filetype string?
+
+
 --- Add and execute text as if entered directly
-function M.execute(text)
+---@param opts dap.repl.execute.opts?
+function M.execute(text, opts)
   M.append("dap> " .. text .. "\n", "$", { newline = true })
   local numlines = api.nvim_buf_line_count(repl.buf)
   if repl.win and api.nvim_win_is_valid(repl.win) then
@@ -310,7 +357,7 @@ function M.execute(text)
       vim.cmd.normal({"zt", bang = true })
     end)
   end
-  execute(text)
+  execute(text, opts)
 end
 
 

lua/dap/session.lua

@@ -535,7 +535,7 @@ end
 local function jump_to_frame(session, frame, preserve_focus_hint, stopped)
   local source = frame.source
   if not source then
-    utils.notify('Source not available, cannot jump to frame', vim.log.levels.INFO)
+    utils.notify('Source missing, cannot jump to frame: ' .. frame.name, vim.log.levels.INFO)
     return
   end
   vim.fn.sign_unplace(session.sign_group)
@@ -544,7 +544,7 @@ local function jump_to_frame(session, frame, preserve_focus_hint, stopped)
   end
   local bufnr = frame_to_bufnr(session, frame)
   if not bufnr then
-    utils.notify('Source not available, cannot jump to frame', vim.log.levels.INFO)
+    utils.notify('Source missing, cannot jump to frame: ' .. frame.name, vim.log.levels.INFO)
     return
   end
   vim.fn.bufload(bufnr)

lua/dap/ui/widgets.lua

@@ -652,7 +652,7 @@ function M.sidebar(widget, winopts, wincmd)
 end
 
 
----@param session Session
+---@param session dap.Session
 ---@param expr string
 ---@param max_level integer
 local function get_var_lines(session, expr, max_level)

plugin/dap.lua

@@ -154,7 +154,7 @@ if api.nvim_create_autocmd then
           vim.bo[args.buf].modified = false
           local repl = require("dap.repl")
           local lines = api.nvim_buf_get_lines(args.buf, 0, -1, true)
-          repl.execute(table.concat(lines, "\n"))
+          repl.execute(table.concat(lines, "\n"), { filetype = ft })
           repl.open()
         end,
       })