diff --git a/impls/vbs/printer.vbs b/impls/vbs/printer.vbs
index a10511b4..d0a818df 100644
--- a/impls/vbs/printer.vbs
+++ b/impls/vbs/printer.vbs
@@ -1,4 +1,9 @@
 Function pr_str(o,print_readably)
+	msgbox typename(o) = "Nothing"
+	if typename(o) = "Nothing" then
+		pr_str = ""
+		exit function
+	end if
 	If left(o.type_,4) = "list" Then
 		pr_str =mid(o.type_,5,1) 
 		bool = False
diff --git a/impls/vbs/reader.vbs b/impls/vbs/reader.vbs
index 906f6f33..71173a6d 100644
--- a/impls/vbs/reader.vbs
+++ b/impls/vbs/reader.vbs
@@ -11,6 +11,7 @@ End Class
 'msgbox pr_str(read_str("(123 "))
 Function read_str(str)
 	set read_str=read_form(tokenize(str))
+	'msgbox pr_str(read_str,true)
 End Function
 
 Function tokenize(str)
@@ -33,6 +34,7 @@ End Function
 
 Function read_form_(oQueue)
 	set read_form_=read_form(oQueue)
+	'msgbox pr_str(read_form_),true
 	if oQueue.Count > 0 then
 		err.raise vbObjectError,"SyntaxError", "Extra data after form: " + oQueue.Dequeue
 	end if
@@ -141,10 +143,13 @@ End Function
 
 Function read_atom(oQueue)
 	atom = oQueue.Dequeue()
-	if isnumeric(atom) Then
+	if atom = "" then
+		set read_atom = Nothing
+	elseif isnumeric(atom) Then
 		set read_atom = new MalType
 		read_atom.Type_ = "number"
-		read_atom.value_ = atom
+		read_atom.value_ = cdbl(atom)
+		'msgbox "here"
 	elseif atom = "true" or atom = "false" Then
 		set read_atom = new MalType
 		read_atom.Type_ = "boolean"
diff --git a/impls/vbs/step2_eval.vbs b/impls/vbs/step2_eval.vbs
new file mode 100644
index 00000000..a50ad4c4
--- /dev/null
+++ b/impls/vbs/step2_eval.vbs
@@ -0,0 +1,140 @@
+Include "reader.vbs"
+Include "printer.vbs"
+
+function add(args)
+	set add = new MalType
+	add.type_ = "number"
+	'msgbox typename(args)
+	add.value_ = args.value_.item(1).value_ + args.value_.item(2).value_
+end function
+
+function subtract(args)
+	set subtract = new MalType
+	subtract.type_ = "number"
+	subtract.value_ = args.value_.item(1).value_ - args.value_.item(2).value_
+end function
+
+function multiply(args)
+	set multiply = new MalType
+	multiply.type_ = "number"
+	multiply.value_ = args.value_.item(1).value_ * args.value_.item(2).value_
+end function
+
+function divide(args)
+	set divide = new MalType
+	divide.type_ = "number"
+	divide.value_ = args.value_.item(1).value_ / args.value_.item(2).value_
+end function
+
+function donothing(args)
+	set donothing = new MalType
+	donothing.type_ = "nil"
+	donothing.value_ = "error"
+end function
+
+class enviroment
+	public env
+	private sub Class_Initialize()
+		set env = CreateObject("Scripting.Dictionary")
+		env.add "+",getref("add")
+		env.add "-",getref("subtract")
+		env.add "*",getref("multiply")
+		env.add "/",getref("divide")
+		env.add "donothing", getref("donothing")
+	end sub
+
+end class
+
+Function READ(str)
+    set READ = read_str(str)
+End Function
+
+Function EVAL(oMal,env)
+	'msgbox typename(o)
+	if isempty(o) then
+		set EVAL = donothing("")
+		exit function
+	end if
+	select case oMal.type_
+		case "list()"
+			if oMal.value_.count = 0 then
+				set EVAL = oMal
+			else
+				'wsh.echo oMal.value_.item(0).value_
+				'wsh.echo typename(env.env)
+				'msgbox eval_ast(oMal.value_.item(1),env).value_
+				'msgbox typename(env.env.item("+")(oMal))
+				'if not isempty(oMal.value_.item(0)) then
+					set EVAL = env.env.item(eval_ast(oMal.value_.item(0),env).value_)(eval_ast(oMal,env))
+				'else
+				'end if
+			end if
+		case else 
+			set EVAL = eval_ast(oMal,env)
+	end select
+End Function
+
+function eval_ast(ast,env)
+	select case ast.type_
+		case "list()"
+			for i = 0 to ast.value_.count - 1
+				set ast.value_.item(i) = EVAL(ast.value_.item(i),env)
+			next
+			set eval_ast = ast
+		case "symbol"
+			if env.env.Exists(ast.value_) then
+				set eval_ast = ast
+			else
+				'err.raise vbObjectError, "eval_ast", "undefined symbol: " & ast.value_
+				wsh.echo "undefined symbol: " & ast.value_
+				ast.value_ = "donothing"
+				set eval_ast = ast
+			end if
+		case "list[]"
+			for i = 0 to ast.value_.count - 1
+				set ast.value_.item(i) = EVAL(ast.value_.item(i),env)
+			next
+			set eval_ast = ast
+		case "hash-map"
+			For i = 0 To ast.value_.Count -1 ' 迭代数组。
+				' wsh.echo ast.value_.keys()(i).value_
+				' wsh.echo ast.value_.item(ast.value_.keys()(i)).value_
+				set ast.value_.item(ast.value_.keys()(i)) = EVAL(ast.value_.item(ast.value_.keys()(i)),env)
+			Next
+			set eval_ast = ast
+		case else
+			set eval_ast = ast
+	end select
+end function
+
+
+Function PRINT(oMal)
+    PRINT = pr_str(oMal,true)
+End Function
+
+Function rep(str,env)
+	'on error resume next
+    rep = PRINT(EVAL(READ(str),env))
+	'msgbox 2
+	if err.number <> 0 then rep = err.description
+	on error goto 0
+End Function
+
+While True
+    WScript.StdOut.Write("user> ")
+    code = WScript.StdIn.ReadLine()
+	set env = new enviroment
+    WScript.Echo(rep(code,env))
+WEnd
+
+Sub Include(sInstFile) 
+	Dim oFSO, f, s 
+	Set oFSO = CreateObject("Scripting.FileSystemObject")
+    sInstFile = oFSO.GetParentFolderName(oFSO.GetFile(Wscript.ScriptFullName)) & "\" & sInstFile
+	Set f = oFSO.OpenTextFile(sInstFile) 
+	s = f.ReadAll 
+	f.Close 
+	Set f = Nothing
+	Set oFSO = Nothing
+	ExecuteGlobal s 
+End Sub
\ No newline at end of file