add a cool lua repl

lib/lua-repl/repl/utils.lua

@@ -0,0 +1,70 @@
+-- Copyright (c) 2011-2015 Rob Hoelz <rob@hoelz.ro>
+--
+-- Permission is hereby granted, free of charge, to any person obtaining a copy of
+-- this software and associated documentation files (the "Software"), to deal in
+-- the Software without restriction, including without limitation the rights to
+-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+-- the Software, and to permit persons to whom the Software is furnished to do so,
+-- subject to the following conditions:
+--
+-- The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+-- FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+-- COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+-- IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+-- CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+local setfenv = setfenv or function(f, t)
+  local upvalue_index = 1
+
+  -- XXX we may need a utility library if debug isn't available
+  while true do
+    local name = debug.getupvalue(f, upvalue_index)
+    -- some functions don't have an _ENV upvalue, because
+    -- they never refer to globals
+    if not name then
+      return
+    end
+    if name == '_ENV' then
+      debug.setupvalue(f, upvalue_index, t)
+      return
+    end
+    upvalue_index = upvalue_index + 1
+  end
+end
+
+--- Tests wheter an expression ends in an unfinished string literal.
+-- @return First position in the unfinished string literal or `nil`.
+local function ends_in_unfinished_string(expr)
+  local position = 0
+  local quote
+  local current_delimiter
+  local last_unmatched_start
+  while true do
+    -- find all quotes:
+    position, quote = expr:match('()([\'"])', position+1)
+    if not position then break end
+    -- if we're currently in a string:
+    if current_delimiter then
+      -- would end current string?
+      if current_delimiter == quote then
+        -- not escaped?
+        if expr:sub(position-1, position-1) ~= '\\' then
+          current_delimiter = nil
+          last_unmatched_start = nil
+        end
+      end
+    else
+      current_delimiter = quote
+      last_unmatched_start = position+1
+    end
+  end
+  return last_unmatched_start
+end
+
+return {
+  setfenv = setfenv,
+  ends_in_unfinished_string = ends_in_unfinished_string
+}