feat(watches): add visual/cexpr expression

See #160

Author: rcarriga

lua/dapui/elements/watches.lua

@@ -32,8 +32,11 @@ return function(client)
   })
 
   --- Add a new watch expression
-  ---@param expr string
+  ---@param expr? string
   function dapui.elements.watches.add(expr)
+    if not expr then
+      expr = util.get_current_expr()
+    end
     watches.add(expr)
   end
 

lua/dapui/init.lua

@@ -226,7 +226,7 @@ local prev_expr = nil
 ---
 --- If no fixed dimensions are given, the window will expand to fit the contents
 --- of the buffer.
----@param expr string Expression to evaluate. If nil, then in normal more the
+---@param expr? string Expression to evaluate. If nil, then in normal more the
 --- current word is used, and in visual mode the currently highlighted text.
 ---@param args dapui.EvalArgs
 function dapui.eval(expr, args)
@@ -237,14 +237,7 @@ function dapui.eval(expr, args)
     end
     args = args or {}
     if not expr then
-      if vim.fn.mode() == "v" then
-        local start = async.fn.getpos("v")
-        local finish = async.fn.getpos(".")
-        local lines = util.get_selection(start, finish)
-        expr = table.concat(lines, "\n")
-      else
-        expr = expr or async.fn.expand("<cexpr>")
-      end
+      expr = util.get_current_expr()
     end
     if open_float then
       if prev_expr == expr then

lua/dapui/util.lua

@@ -26,6 +26,16 @@ function M.create_render_loop(render)
   end
 end
 
+function M.get_current_expr()
+  if async.fn.mode() == "v" then
+    local start = async.fn.getpos("v")
+    local finish = async.fn.getpos(".")
+    local lines = M.get_selection(start, finish)
+    return table.concat(lines, "\n")
+  end
+  return async.fn.expand("<cexpr>")
+end
+
 function M.create_buffer(name, options)
   local buf = async.api.nvim_create_buf(true, true)
   options = vim.tbl_extend("keep", options or {}, {