Add dap-eval:// buffer support

Acts as a scratchpad for expression evaluation or multi-line input for
the REPL

lua/dap/repl.lua

@@ -303,6 +303,13 @@ end
 --- Add and execute text as if entered directly
 function M.execute(text)
   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
+    pcall(api.nvim_win_set_cursor, repl.win, { numlines, 0 })
+    api.nvim_win_call(repl.win, function()
+      vim.cmd.normal({"zt", bang = true })
+    end)
+  end
   execute(text)
 end
 
@@ -344,8 +351,10 @@ local function select_history(delta)
   local text = history.entries[history.idx]
   if text then
     local lnum = vim.fn.line('$')
-    api.nvim_buf_set_lines(repl.buf, lnum - 1, lnum, true, {'dap> ' .. text })
-    vim.fn.setcursorcharpos({ lnum, vim.fn.col('$') })  -- move cursor to the end of line
+    local lines = vim.split(text, "\n", { plain = true })
+    lines[1] = "dap> " .. lines[1]
+    api.nvim_buf_set_lines(repl.buf, lnum - 1, -1, true, lines)
+    vim.fn.setcursorcharpos({ vim.fn.line("$"), vim.fn.col('$') })  -- move cursor to the end of line
   end
 end
 

plugin/dap.lua

@@ -29,10 +29,10 @@ cmd('DapRestartFrame', function() require('dap').restart_frame() end, { nargs =
 
 
 if api.nvim_create_autocmd then
-  local group = api.nvim_create_augroup('dap-launch.json', { clear = true })
+  local launchjson_group = api.nvim_create_augroup('dap-launch.json', { clear = true })
   local pattern =  '*/.vscode/launch.json'
   api.nvim_create_autocmd('BufNewFile', {
-    group = group,
+    group = launchjson_group,
     pattern = pattern,
     callback = function(args)
       local lines = {
@@ -51,10 +51,41 @@ if api.nvim_create_autocmd then
     end
   })
   api.nvim_create_autocmd('BufWritePost', {
-    group = group,
+    group = launchjson_group,
     pattern = pattern,
     callback = function(args)
       require('dap.ext.vscode').load_launchjs(args.file)
     end
   })
+
+  api.nvim_create_autocmd("BufReadCmd", {
+    group = api.nvim_create_augroup("dap-readcmds", { clear = true }),
+    pattern = "dap-eval://*",
+    callback = function()
+      local bufnr = api.nvim_get_current_buf()
+      local fname = api.nvim_buf_get_name(bufnr)
+      vim.bo[bufnr].swapfile = false
+      vim.bo[bufnr].buftype = "acwrite"
+      vim.bo[bufnr].bufhidden = "wipe"
+      local ft = fname:match("dap%-eval://(%w+)(.*)")
+      if ft and ft ~= "" then
+        vim.bo[bufnr].filetype = ft
+      else
+        local altbuf = vim.fn.bufnr("#", false)
+        if altbuf then
+          vim.bo[bufnr].filetype = vim.bo[altbuf].filetype
+        end
+      end
+      api.nvim_create_autocmd("BufWriteCmd", {
+        buffer = bufnr,
+        callback = function(args)
+          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.open()
+        end,
+      })
+    end,
+  })
 end