--- a/core/src/luan/modules/Io.luan	Thu Jun 18 03:14:07 2015 -0600
+++ b/core/src/luan/modules/Io.luan	Thu Jun 18 03:30:18 2015 -0600
@@ -14,17 +14,19 @@
 
 
 local Luan = require "luan:Luan"
-local to_string = Luan.to_string
-local type = Luan.type
-local try = Luan.try
-local ipairs = Luan.ipairs
-local pairs = Luan.pairs
-local values = Luan.values
+local error = Luan.error
+local to_string = Luan.to_string or error()
+local type = Luan.type or error()
+local try = Luan.try or error()
+local ipairs = Luan.ipairs or error()
+local pairs = Luan.pairs or error()
+local values = Luan.values or error()
+local load = Luan.load or error()
 local Table = require "luan:Table"
-local unpack = Table.unpack
+local unpack = Table.unpack or error()
 local String = require "luan:String"
-local encode = String.encode
-local matches = String.matches
+local encode = String.encode or error()
+local matches = String.matches or error()
 
 
 function M.print_to(out,...)
@@ -33,9 +35,7 @@
 		list[#list+1] = to_string(v)
 		list[#list+1] = '\t'
 	end
-	if #list == 0 then
-		out.write( '\n' )
-	else
+	if #list > 0 then
 		list[#list] = '\n'
 		out.write( unpack(list) )
 	end
@@ -122,4 +122,27 @@
 	end
 end
 
+
+-- debug
+
+function M.debug(prompt)
+	prompt = prompt or "luan_debug> "
+	local function console()
+		return M.read_console_line(prompt)
+	end
+	local env = {}
+	for line in console do
+		try {
+			function()
+				local fn = load(line,"stdin",env,true)
+				M.print( fn() )
+			end;
+			catch = function(e)
+				M.print(e)
+			end;
+		}
+	end
+end
+
+
 return M