X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=XmlExpr.cs;h=733f5923a44a6967760f295cf5816afa89624ccd;hb=eb3ee8c4e2e824505f5a518c67f997d7b29b40a6;hp=ba46189d5b13fd2985501152988433f00b30b5c7;hpb=06a7d21737872397a9dfa8ba7619ca50677ee9de;p=m17n%2Fm17n-lib-cs.git

diff --git a/XmlExpr.cs b/XmlExpr.cs
index ba46189..733f592 100644
--- a/XmlExpr.cs
+++ b/XmlExpr.cs
@@ -6,120 +6,386 @@ using System.Xml;
 
 namespace System.Xml.Expression
 {
-public class XmlName : IEquatable<XmlName>
+  public class Xex
   {
-    private static NameTable nt = new NameTable ();
+    public struct Name : IEquatable<Name>
+    {
+      private static NameTable nt = new NameTable ();
 
-    private object name;
+      private string name;
 
-    private XmlName (string str)
+      public Name (string str)
+	{
+	  name = nt.Add (str);
+	}
+
+      public static implicit operator Name (string str)
       {
-	name = nt.Add (str);
+	return new Name (str);
       }
 
-    public static implicit operator XmlName (string str)
-    {
-      return new XmlName (str);
+      public static implicit operator string (Name name)
+      {
+	return name.name;
+      }
+
+      public static bool operator== (Name n1, Name n2)
+	{
+	  return (object) n1.name == (object) n2.name;
+	}
+
+      public static bool operator!= (Name n1, Name n2)
+	{
+	  return (object) n1.name != (object) n2.name;
+	}
+
+      public static bool operator== (Name n1, string n2)
+	{
+	  return (object) n1.name == (object) n2;
+	}
+
+      public static bool operator!= (Name n1, string n2)
+	{
+	  return (object) n1.name != (object) n2;
+	}
+
+      public bool Equals (Name name)
+      {
+	return Object.ReferenceEquals (this.name, name.name);
+      }
+
+      public override bool Equals (object obj)
+      {
+	return Object.ReferenceEquals (this.name, obj);
+      }
+
+      public override int GetHashCode ()
+      {
+	return name.GetHashCode ();
+      }
+
+      public static NameTable Table { get { return nt; } }
+
+      public override string ToString () { return name; }
     }
 
-    public static bool operator== (XmlName n1, XmlName n2)
+    private static Name Nexpr = "expr";
+    private static Name Ntype = "type";
+    private static Name Nargs = "args";
+
+    private static Name Ninteger = "integer";
+    private static Name Nstring = "string";
+    private static Name Nboolean = "boolean";
+    private static Name Nsymbol = "symbol";
+    private static Name Nlist = "list";
+    private static Name Nobject = "object";
+
+    private static Name Ndefun = "defun";
+    private static Name Ndefmacro = "defmacro";
+    private static Name Ndefvar = "defvar";
+    private static Name Nconst = "const";
+    private static Name Nvariable = "variable";
+    private static Name Ndescription = "description";
+    private static Name Npossible_value = "possible-value";
+
+    private static Name Nfuncall = "funcall";
+    private static Name Nmname = "mname";
+    private static Name Nprogn = "progn";
+
+    internal class Function
+    {
+      internal class Lambda
+      {
+	internal Variable[] args;
+	internal Xex[] body;
+
+	public Lambda (XmlNode node, Domain domain)
+	{
+	  Set (node, domain);
+	}
+
+	public void Set (XmlNode node, Domain domain)
+	{
+	  XmlNodeList body = node.ChildNodes;
+	  int idx = 0;
+
+	  if (Nargs == body[0].Name)
+	    {
+	      XmlNodeList args = body[0].ChildNodes;
+	      if (this.args == null)
+		this.args = new Name[args.Count];
+	      for (int i = 0; i < args.Count; i++)
+		this.args[i] = args[i].InnerText;
+	      idx++;
+	    }
+	  else if (this.args == null)
+	    this.args = new Name[0];
+	  if (this.body == null)
+	    this.body = new Xex[body.Count - idx];
+	  for (int i = 0; idx < body.Count; i++, idx++)
+	    this.body[i] = new Xex (body[idx], domain);
+	}
+      }
+
+      public readonly Name name;
+      public Builtin builtin;
+      public int min_arg, max_arg;
+      internal Lambda lambda;
+      public bool specialp = false;
+
+      public Function (Name name, Builtin builtin,
+		       int min_arg, int max_arg, bool specialp)
+      {
+	this.name = name;
+	this.builtin = builtin;
+	this.min_arg = min_arg;
+	this.max_arg = max_arg;
+	this.specialp = specialp;
+      }
+
+      internal Function (Name name, XmlNode node, Domain domain)
+      {
+	this.name = name;
+	lambda = new Lambda (node, domain);
+	this.min_arg = this.max_arg = lambda.args.Length;
+      }
+
+      internal Function (Name name, int nargs, bool specialp)
       {
-	return n1.name == n2.name;
+	this.name = name;
+	this.min_arg = this.max_arg = nargs;
       }
 
-    public static bool operator!= (XmlName n1, XmlName n2)
+      public object Call (Xex[] args, Domain domain)
       {
-	return n1.name != n2.name;
+	Bindings current = domain.bindings;
+	object result = false;
+
+	Console.Write ("calling (" + this + "(");
+	try {
+	  if (! specialp)
+	    foreach (Xex e in args)
+	      e.Eval (domain);
+	  Console.WriteLine (")");
+	  if (builtin != null)
+	    return builtin (args, domain);
+	  if (lambda == null)
+	    return null;
+	  for (int i = 0; i < args.Length; i++)
+	    domain.Bind (bindings, lambda.args[i], args[i].val);
+	  foreach (Xex e in lambda.body)
+	    {
+	      result = e.Eval (domain);
+	      Console.WriteLine (e.ToString () + "=>" + result);
+	    }
+	} finally {
+	  Console.WriteLine (")");
+	  domain.UnboundTo (current);
+	}
+	return result;
       }
 
-    public bool Equals (XmlName other) { return name == other.name; }
-    public override bool Equals (object obj) { return obj == name; }
-    public override int GetHashCode ()
+      public override string ToString ()
+      {
+	return name;
+      }
+    }
+
+    internal abstract class Variable
     {
-      return ((string) name).GetHashCode ();
+      public readonly Name name;
+      public readonly Name type;
+      internal object val;
+
+      public Variable (Name name, Name type, object value)
+      {
+	this.name = name;
+	this.type = type;
+	val = value;
+      }
+
+      public object Value
+      {
+	get { return val; }
+	set
+	  {
+	    if (! ValueP (value))
+	      throw new Exception ("Invalid value type: " + value);
+	    val = value;
+	  }
+      }
+
+      public abstract bool ValueP (object value);
+
+      public override string ToString () { return name + "(" + type + ")"; }
     }
 
-    public static NameTable Table { get { return nt; } }
-  }
+    internal class VarInt : Variable
+    {
+      public struct Range
+      {
+	public int from, to;
+      }
 
-  public class Xex
-  {
-    private static NameTable nt = new NameTable ();
+      public Range[] ranges;
+
+      public VarInt (Name name, int value) : base (name, Ninteger, value) { }
+
+      public override bool ValueP (object value)
+      {
+	int i;
 
-    public static object Name (string str)
+	if (! (value is int))
+	  return false;
+	if (ranges == null)
+	  return true;
+	i = (int) value;
+	foreach (Range r in ranges)
+	  if (i >= r.from && i <= r.to)
+	    return true;
+	return false;
+      }
+    }
+
+    internal class VarStr : Variable
     {
-      return nt.Add (str);
+      public string[] ranges;
+
+      public VarStr (Name name, string value) : base (name, Nstring, value) { }
+
+      public override bool ValueP (object value)
+      {
+	string str;
+
+	if (! (value is string))
+	  return false;
+	if (ranges == null)
+	  return true;
+	str = (string) value;
+	foreach (string s in ranges)
+	  if (s == str)
+	    return true;
+	return false;
+      }
     }
 
-    public static NameTable Table { get { return nt; } }
+    internal class VarBool : Variable
+    {
+      public VarBool (Name name, bool value) : base (name, Nboolean, value) { }
 
-    private static object Nvar = Name ("var");
-    private static object Ndefun = Name ("defun");
-    private static object Ncond = Name ("cond");
-    private static object Nprogn = Name ("progn");
-    private static object Nwhen = Name ("when");
+      public override bool ValueP (object value)
+      {
+	return value is bool;
+      }
+    }
 
-    public class Domain
+    internal class VarMisc : Variable
     {
-      private Domain parent;
-      internal Dictionary<object,functions = new MPlist ();
-      internal MPlist bindings = new MPlist ();
-      private Stack<MPlist> boundaries = new Stack<MPlist> ();
-      internal Translator translator;
-      public object context;
+      public VarMisc (Name name, object value) : base (name, Nobject, value) { }
 
-      internal Domain ()
+      public override bool ValueP (object value)
       {
-	boundaries.Push (bindings);
+	return true;
       }
+    }
 
-      public Domain (object context) : this (basic, context) { }
+    internal class Bindings
+    {
+      private Variable vari;
+      private object old_value;
+      private Bindings next;
+	
+      private Bindings (Variable vari, object value)
+      {
+	this.vari = vari;
+	old_value = value;
+      }
+	
+      public static Bindings Bind (Bindings bindings,
+				   Variable vari, object value)
+      {
+	Bindings b = new Bindings (vari, vari.val);
 
-      public Domain (Domain parent, object context)
+	b.vari.Value = value;
+	b.next = bindings;
+	return b;
+      }
+
+      internal Bindings UnboundTo (Bindings boundary)
       {
-	this.parent = parent;
-	this.context = context;
-	boundaries.Push (bindings);
+	for (Bindings b = this; b != boundary; b = b.next)
+	  vari.val = b.old_value;
+	return boundary;
       }
 
-      public void AddTranslator (Translator translator)
+      public override string ToString ()
       {
-	if (this.translator == null)
-	  this.translator = translator;
-	else
-	  this.translator += translator;
+	string str = "(bindings";
+	for (Bindings b = this; b != null; b = b.next)
+	  str += " " + vari;
+	return str + ")";
       }
+    }
+
+#if false
+    internal class ThrowException : Exception
+    {
+      Name tag;
+      public object value;
+
+      public ThrowException (Name tag, object value) : base ()
+	{
+	  this.tag = tag;
+	  this.value = value;
+	}
+    }
+#endif
 
-      public void Bind (MSymbol sym, object value)
+    public class Domain
+    {
+      private Domain parent;
+      public object context;
+
+      internal Dictionary<Name, Function> functions
+	= new Dictionary<Name, Function> ();
+      internal Dictionary<Name, Variable> variables
+	= new Dictionary<Name, Variable> ();
+      internal Bindings bindings;
+
+      internal Domain () { }
+
+      public Domain (object context) : this (basic, context)
       {
-	bindings = bindings.Cons (sym, value);
       }
 
-      public MPlist SetBoundary ()
+      public Domain (Domain parent, object context)
+      {
+	this.parent = parent;
+	this.context = context;
+      }
+
+      internal void Bind (Variable vari, object value)
       {
-	boundaries.Push (bindings);
-	return bindings;
+	bindings = Bindings.Bind (bindings, vari, value);
       }
 
-      public void UnboundTo (MPlist boundary)
+      internal void UnboundTo (Bindings boundary)
       {
-	while (boundary != boundaries.Pop ());
-	while (bindings != boundary)
-	  bindings = bindings.next;
+	if (boundary != null)
+	  bindings = bindings.UnboundTo (boundary);
       }
 
-      public void Defun (string name, Builtin builtin, int min_arg, int max_arg)
+      public void Defun (Name name, Builtin builtin, int min_arg, int max_arg)
       {
 	Defun (name, builtin, min_arg, max_arg, false);
       }
 
-      public void Defun (string name, Builtin builtin, int min_arg, int max_arg,
+      public void Defun (Name name, Builtin builtin, int min_arg, int max_arg,
 			 bool specialp)
       {
-	MSymbol sym = name;
-	Function func = (Function) functions.Get (sym);
+	Function func;
 
-	if (func != null)
+	if (functions.TryGetValue (name, out func))
 	  {
 	    if (func.min_arg < min_arg || func.max_arg > max_arg)
 	      throw new Exception ("Incompatible argument numbers to override: "
@@ -132,61 +398,130 @@ public class XmlName : IEquatable<XmlName>
 	  }
 	else
 	  {
-	    func = new Function (sym, builtin, min_arg, max_arg, specialp);
-	    functions = functions.Cons (sym, func);
+	    functions[name]
+	      = new Function (name, builtin, min_arg, max_arg, specialp);
 	  }
       }
 
-      public void Defun (MSymbol sym, MPlist args, MPlist body)
+      public void Defun (XmlNode node)
       {
-	Function func = (Function) functions.Get (sym);
+	Name name = node.Attributes[0].Value;
+	Function func;
 
-	if (func != null)
+	if (functions.TryGetValue (name, out func))
 	  {
-	    int nargs = args == null ? 0 : args.Count;
+	    XmlNode args = node.FirstChild;
+	    int nargs = args.Name == Nargs ? args.ChildNodes.Count : 0;
 
 	    if (func.min_arg < nargs || func.max_arg > nargs)
 	      throw new Exception ("Incompatible argument numbers to override: "
-				   + sym);
-	    func.lambda.SetArgs (args);
-	    func.lambda.SetBody (body, this);
+				   + name);
+	    if (func.lambda == null)
+	      func.lambda = new Function.Lambda (node, this);
+	    else
+	      func.lambda.Set (node, this);
 	    func.builtin = null;
 	  }
 	else
 	  {
-	    func = new Function (sym, args, body, this);
-	    functions = functions.Cons (sym, func);
+	    func = new Function (name, node, this);
+	    functions[name] = func;
 	  }	    
       }
 
-      public void Defun (XmlNode node)
+      public void Defun (Name name, int nargs, bool specialp)
       {
-	MSymbol sym = node.Attributes["id"].Value;
-	Function func = (Function) functions.Get (sym);
+	Function func;
 
-	if (func != null)
+	if (functions.TryGetValue (name, out func))
 	  {
-	    XmlNode args = node.FirstChild;
-	    int nargs = args.Name == "args" ? args.ChildNodes.Count : 0;
-
 	    if (func.min_arg < nargs || func.max_arg > nargs)
 	      throw new Exception ("Incompatible argument numbers to override: "
-				   + sym);
-	    func.lambda.Set (node, this);
+				   + name);
+	    func.min_arg = func.max_arg = nargs;
+	    func.specialp = specialp;
 	    func.builtin = null;
 	  }
 	else
 	  {
-	    func = new Function (sym, node, this);
-	    functions = functions.Cons (sym, func);
+	    func = new Function (name, nargs, specialp);
+	    functions[name] = func;
 	  }	    
       }
 
-      internal Function GetFunc (MSymbol name)
+      public void Defvar (Name name, XmlNode node)
       {
-	Function func = (Function) functions.Get (name);
+	Variable vari;
 
-	if (func == null)
+	if (node.Name == Ndescription)
+	  node = node.NextSibling;
+	if (node.Name == Nconst)
+	  {
+	    Name type = (Name) node.Attributes[Ntype].Value;
+	    string val = node.Value;
+	    XmlNodeList range_list = null;
+	    int nranges = 0;
+
+	    node = node.NextSibling;
+	    if (node.Name == Npossible_value)
+	      {
+		range_list = node.ChildNodes;
+		nranges = range_list.Count;
+	      }
+
+	    if (type == Ninteger)
+	      {
+		VarInt vi = new VarInt (name, parse_integer (val));
+		if (range_list != null)
+		  {
+		    vi.ranges = new VarInt.Range[nranges];
+
+		    for (int i = 0; i < nranges; i++)
+		      {
+			XmlNode n = range_list[i];
+
+			if (n.Name == Nconst)
+			  {
+			    int num = parse_integer (n.Value);
+			    vi.ranges[i].from = vi.ranges[i].to = num;
+			  }
+			else	// range_list[i].Name == "range"
+			  {
+			    vi.ranges[i].from =
+			      parse_integer (n.FirstChild.Value);
+			    vi.ranges[i].to =
+			      parse_integer (n.LastChild.Value);
+			  }
+		      }
+		  }
+		vari = vi;
+	      }
+	    else if (type == Nstring)
+	      {
+		VarStr vs = new VarStr (name, val);
+		if (range_list != null)
+		  vs.ranges = new string[nranges];
+		for (int i = 0; i < nranges; i++)
+		  vs.ranges[i] = range_list[i].Value;
+		vari = vs;
+	      }
+	    else if (type == Nboolean)
+	      {
+		vari = new VarBool (name, val == "true");
+	      }
+	    else
+	      throw new Exception ("Unknown type: " + type);
+	  }
+	else
+	  vari = new VarMisc (name, null);
+	variables[name] = vari;
+      }
+
+      internal Function GetFunc (Name name)
+      {
+	Function func;
+
+	if (! functions.TryGetValue (name, out func))
 	  {
 	    if (parent != null)
 	      return parent.GetFunc (name);
@@ -195,68 +530,47 @@ public class XmlName : IEquatable<XmlName>
 	return func;
       }
 
-      public bool CopyFunc (Domain domain, MSymbol name)
+      public bool CopyFunc (Domain domain, Name name)
       {
-	Function func = (Function) functions.Get (name);
-	if (func == null)
-	  return false;
-	domain.functions = domain.functions.Cons (name, func);
+	Function func = GetFunc (name);
+
+	domain.functions[name] = func;
 	return true;
       }
 
       public void CopyFunc (Domain domain)
       {
-	foreach (MPlist p in functions)
-	  domain.functions = domain.functions.Cons (p.key, p.val);
-      }
-
-      public object GetValue (MSymbol name)
-      {
-	MPlist slot = bindings.Find (name);
-
-	if (slot == null)
-	  {
-	    if (parent != null)
-	      return parent.GetValue (name);
-	    throw new Exception ("Unbound variable: " + name);
-	  }
-	return slot.val;
+	foreach (KeyValuePair<Name, Function> kv in functions)
+	  domain.functions[kv.Key] = kv.Value;
       }
 
-      public object SetValue (MSymbol name, object val)
+      internal Variable GetVar (Name name)
       {
-	MPlist boundary = boundaries.Peek ();
+	Variable vari;
 
-	for (MPlist plist = bindings; plist != boundary; plist = plist.next)
-	  if (plist.key == name)
-	    {
-	      plist.val = val;
-	      return val;
-	    }
-	bindings = bindings.Cons (name, val);
-	return val;
-      }
-
-      public bool IsBound (MSymbol name)
-      {
-	return (bindings.Find (name) != null);
+	if (! variables.TryGetValue (name, out vari))
+	  variables[name] = vari = new VarMisc (name, null);
+	return vari;
       }
 
-      public void Translate (MPlist plist)
+      internal Variable GetVar (Xex e)
       {
-	if (parent != null)
-	  parent.Translate (plist);
-	if (translator != null)
-	  for (MPlist p = plist; ! p.IsEmpty; p = p.next)
-	    translator (p, this);
+	if (! (e.val is Name))
+	  throw new Exception ("Not a symbol" + e.val);
+	return GetVar ((Name) e.val);
       }
 
       public override string ToString ()
       {
 	string str = "<(functions";
-	foreach (MPlist p in functions)
-	  str += " " + p.key;
-	str += ") (bindings " + bindings + ")";
+	foreach (KeyValuePair<Name, Function> kv in functions)
+	  str += " " + kv.Key;
+	str += ") (variabls";
+	foreach (KeyValuePair<Name, Variable> kv in variables)
+	  str += " " + kv.Key;
+	str += ")";
+	if (bindings != null)
+	  str += " " + bindings;
 	if (context != null)
 	  str += " (" + context + ")";
 	str += ">";
@@ -264,232 +578,132 @@ public class XmlName : IEquatable<XmlName>
       }
     }
 
-    public delegate object Builtin (MExpression[] args, Domain domain);
-    public delegate void Translator (MPlist plist, Domain domain);
+    public delegate object Builtin (Xex[] args, Domain domain);
 
-    internal class Function
-    {
-      internal class Lambda
-      {
-	internal MSymbol[] args;
-	internal MExpression[] body;
+    private static Domain basic = new Domain ();
 
-	public Lambda (MPlist args, MPlist body, Domain domain)
-	{
-	  SetArgs (args);
-	  SetBody (body, domain);
-	}
+    internal static Function Fprogn;
 
-	public Lambda (XmlNode node, Domain domain)
-	{
-	  Set (node, domain);
-	}
-
-	public void SetArgs (MPlist args)
-	{
-	  int len = args == null ? 0 : args.Count;
-
-	  if (this.args == null)
-	    this.args = new MSymbol[len];
-	  for (int i = 0; i < len; i++, args = args.next)
-	    this.args[i] = args.Symbol;
-	}
-
-	public void SetBody (MPlist body, Domain domain)
-	{
-	  int len = body == null ? 0 : body.Count;
-	  if (this.body == null)
-	    this.body = new MExpression[len];
-	  for (int i = 0; i < len; i++, body = body.next)
-	    {
-	      domain.Translate (body);
-	      this.body[i] = new MExpression (body.key, body.val, domain);
-	    }
-	}
-
-	public void Set (XmlNode node, Domain domain)
-	{
-	  XmlNodeList body = node.ChildNodes;
-	  int idx = 0;
-
-	  if (body[0].Name == "args")
-	    {
-	      XmlNodeList args = body[0].ChildNodes;
-	      if (this.args == null)
-		this.args = new MSymbol[args.Count];
-	      for (int i = 0; i < args.Count; i++)
-		this.args[i] = args[i].InnerText;
-	      idx++;
-	    }
-	  else if (this.args == null)
-	    this.args = new MSymbol[0];
-	  if (this.body == null)
-	    this.body = new MExpression[body.Count - idx];
-	  for (int i = 0; idx < body.Count; i++, idx++)
-	    this.body[i] = new MExpression (body[idx], domain);
-	}
-      }
-
-      public readonly MSymbol Name;
-      public Builtin builtin;
-      public int min_arg, max_arg;
-      internal Lambda lambda;
-      public bool specialp = false;
-
-      internal static Function ignore, varref, block;
-
-      public Function (MSymbol name, Builtin builtin,
-		       int min_arg, int max_arg, bool specialp)
-      {
-	Name = name;
-	this.builtin = builtin;
-	this.min_arg = min_arg;
-	this.max_arg = max_arg;
-	this.specialp = specialp;
-      }
-
-      internal Function (MSymbol name, MPlist args, MPlist body,
-			 Domain domain)
-      {
-	Name = name;
-	lambda = new Lambda (args, body, domain);
-	this.min_arg = this.max_arg = lambda.args.Length;
-      }
-
-      internal Function (MSymbol name, XmlNode node, Domain domain)
-      {
-	Name = name;
-	lambda = new Lambda (node, domain);
-	this.min_arg = this.max_arg = lambda.args.Length;
-      }
-
-      private Function ()
-      {
-	Name = MSymbol.nil;
-      }
-
-      static Function ()
-      {
-	ignore = new Function ();
-	varref = new Function (Mvarref, get_value, 1, 1, true);
-	block = new Function (Mprogn, progn, 0, -1, true);
-      }
-
-      private static object get_value (MExpression[] args, Domain domain)
-      {
-	return domain.GetValue ((MSymbol) args[0].val);
-      }
-
-      public object Call (MExpression[] args, Domain domain)
-      {
-	if (builtin != null)
-	  {
-	    if (! specialp)
-	      foreach (MExpression e in args)
-		e.Eval (domain);
-	    return builtin (args, domain);
-	  }
-	if (lambda == null)
-	  return null;
-	MPlist orig_bindings = domain.bindings;
-	object result = false;
-	try {
-	  int i = 0;
-	  foreach (MSymbol arg in lambda.args)
-	    domain.Bind (arg, args[i++].Eval (domain));
-	  foreach (MExpression e in lambda.body)
-	    result = e.Eval (domain);
-	} finally {
-	  domain.bindings = orig_bindings;
-	}
-	return result;
-      }
-    }
-
-    private static Domain basic;
-
-    static MExpression ()
+    static Xex ()
     {
-      basic = new Domain ();
-
-      basic.Defun ("set", set_value, 2, 2, true);
-      basic.Defun ("=", set_value, 2, 2, true);
+      basic.Defun ("set", set_value, 2, 2, false);
+      basic.Defun ("=", set_value, 2, 2, false);
+      basic.Defun ("and", and, 1, -1, false);
+      basic.Defun ("&&", and, 1, -1, false);
+      basic.Defun ("or", or, 1, -1, false);
+      basic.Defun ("||", or, 1, -1, false);
+      basic.Defun ("not", not, 1, 1, false);
       basic.Defun ("!", not, 1, 1, false);
-      basic.Defun ("+", plus, 2, -1, false);
-      basic.Defun ("*", multi, 2, -1, false);
-      basic.Defun ("-", minus, 1, -1, false);
-      basic.Defun ("/", divide, 2, -1, false);
-      basic.Defun ("%", percent, 2, -1, false);
+      basic.Defun ("add", add, 2, -1, false);
+      basic.Defun ("+", add, 2, -1, false);
+      basic.Defun ("mul", mul, 2, -1, false);
+      basic.Defun ("*", mul, 2, -1, false);
+      basic.Defun ("sub", sub, 1, -1, false);
+      basic.Defun ("-", sub, 1, -1, false);
+      basic.Defun ("div", div, 2, -1, false);
+      basic.Defun ("/", div, 2, -1, false);
+      basic.Defun ("mod", mod, 2, 2, false);
+      basic.Defun ("%", mod, 2, 2, false);
+      basic.Defun ("logior", logior, 2, -1, false);
       basic.Defun ("|", logior, 2, -1, false);
+      basic.Defun ("logand", logand, 2, -1, false);
       basic.Defun ("&", logand, 2, -1, false);
-      basic.Defun ("+=", pluseq, 2, -1, true);
-      basic.Defun ("*=", multieq, 2, -1, true);
-      basic.Defun ("-=", minuseq, 2, -1, true);
-      basic.Defun ("/=", divideeq, 2, -1, true);
-      basic.Defun ("%=", percenteq, 2, -1, true);
-      basic.Defun ("|=", logioreq, 2, -1, true);
-      basic.Defun ("&=", logandeq, 2, -1, true);
-      basic.Defun ("<<", lshift, 2, 2, false);
-      basic.Defun (">>", rshift, 2, 2, false);
-      basic.Defun ("<<=", lshifteq, 2, 2, true);
-      basic.Defun (">>=", rshifteq, 2, 2, true);
+      basic.Defun ("add-set", add_set, 2, -1, true);
+      basic.Defun ("+=", add_set, 2, -1, true);
+      basic.Defun ("mul-set", mul_set, 2, -1, true);
+      basic.Defun ("*=", mul_set, 2, -1, true);
+      basic.Defun ("sub-set", sub_set, 2, -1, true);
+      basic.Defun ("-=", sub_set, 2, -1, true);
+      basic.Defun ("div-set", div_set, 2, -1, true);
+      basic.Defun ("/=", div_set, 2, -1, true);
+      basic.Defun ("mod-set", mod_set, 2, 2, true);
+      basic.Defun ("%=", mod_set, 2, 2, true);
+      basic.Defun ("logior-set", logior_set, 2, -1, true);
+      basic.Defun ("|=", logior_set, 2, -1, true);
+      basic.Defun ("logand-set", logand_set, 2, -1, true);
+      basic.Defun ("&=", logand_set, 2, -1, true);
+      basic.Defun ("lsh", lsh, 2, 2, false);
+      basic.Defun ("<<", lsh, 2, 2, false);
+      basic.Defun ("rsh", rsh, 2, 2, false);
+      basic.Defun (">>", rsh, 2, 2, false);
+      basic.Defun ("lsh-set", lsh_set, 2, 2, true);
+      basic.Defun ("<<=", lsh_set, 2, 2, true);
+      basic.Defun ("rsh-set", rsh_set, 2, 2, true);
+      basic.Defun (">>=", rsh_set, 2, 2, true);
+      basic.Defun ("eq", eq, 2, -1, false);
       basic.Defun ("==", eq, 2, -1, false);
+      basic.Defun ("noteq", noteq, 2, 2, false);
       basic.Defun ("!=", noteq, 2, 2, false);
-      basic.Defun ("<", less, 2, -1, false);
-      basic.Defun ("<=", lesseq, 2, -1, false);
-      basic.Defun (">", more, 2, -1, false);
-      basic.Defun (">=", moreeq, 2, -1, false);
-      basic.Defun ("progn", progn, 0, -1, true);
-      basic.Defun ("if", ifclause, 2, -1, true);
-      basic.Defun ("when", whenclause, 1, -1, true);
-      basic.Defun ("while", whileclause, 1, -1, true);
-
-      basic.AddTranslator (new Translator (translate_cond));
+      basic.Defun ("lt", less_than, 2, -1, false);
+      basic.Defun ("<", less_than, 2, -1, false);
+      basic.Defun ("le", less_eq, 2, -1, false);
+      basic.Defun ("<=", less_eq, 2, -1, false);
+      basic.Defun ("gt", greater_than, 2, -1, false);
+      basic.Defun (">", greater_than, 2, -1, false);
+      basic.Defun ("ge", greater_eq, 2, -1, false);
+      basic.Defun (">=", greater_eq, 2, -1, false);
+      basic.Defun ("progn", progn_clause, 0, -1, true);
+      basic.Defun ("expr", progn_clause, 0, -1, true);
+      basic.Defun ("if", if_clause, 2, -1, true);
+      basic.Defun ("when", when_clause, 1, -1, true);
+      basic.Defun ("while", while_clause, 1, -1, true);
+
+      Fprogn = basic.GetFunc (Nprogn);
+    }
+
+    private static bool is_true (object val)
+    {
+      return (val is bool ? (bool) val
+	      : val is int ? (int) val == 0
+	      : true);
     }
 
-    private static object set_value (MExpression[] args, Domain domain)
+    private static object set_value (Xex[] args, Domain domain)
     {
-      return domain.SetValue ((MSymbol) args[0].args[0].val,
-			      args[1].Eval (domain));
+      Variable vari = domain.GetVar (args[0]);
+
+      vari.Value = args[1].val;
+      return vari.val;
     }
 
-    private static object not (MExpression[] args, Domain domain)
+    private static object and (Xex[] args, Domain domain)
     {
-      if (args[0].val is int)
-	return (int) args[0].val == 0;
-      if (args[0].val is bool)
-	return ! ((bool) args[0].val);
+      foreach (Xex arg in args)
+	if (! is_true (arg.val))
+	  return false;
       return true;
     }
 
-    private static object plus (MExpression[] args, Domain domain)
+    private static object or (Xex[] args, Domain domain)
     {
-      if (args[0].val is int)
-	{
-	  int n = 0;
-	  foreach (MExpression e in args)
-	    n += (int) e.val;
-	  return n;
-	}
-      else if (args[0].val is MText)
-	{
-	  MText mt = new MText ();
-	  foreach (MExpression e in args)
-	    mt += (MText) e.val;
-	  return mt;
-	}
-      throw new Exception ("Not an integer nor MText: " + args[0].val);
+      foreach (Xex arg in args)
+	if (is_true (arg.val))
+	  return true;
+      return false;
     }
 
-      private static object multi (MExpression[] args, Domain domain)
+    private static object not (Xex[] args, Domain domain)
+    {
+      return ! is_true (args[0].val);
+    }
+
+    private static object add (Xex[] args, Domain domain)
+    {
+      int n = 0;
+      foreach (Xex e in args)
+	n += (int) e.val;
+      return n;
+    }
+
+      private static object mul (Xex[] args, Domain domain)
       {
 	int n = 1;
-	foreach (MExpression e in args)
+	foreach (Xex e in args)
 	  n *= (int) e.val;
 	return n;
       }
 
-      private static object minus (MExpression[] args, Domain domain)
+      private static object sub (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	if (args.Length == 1)
@@ -499,7 +713,7 @@ public class XmlName : IEquatable<XmlName>
 	return n;
       }
 
-      private static object divide (MExpression[] args, Domain domain)
+      private static object div (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -507,142 +721,135 @@ public class XmlName : IEquatable<XmlName>
 	return n;
       }
 
-      private static object percent (MExpression[] args, Domain domain)
+      private static object mod (Xex[] args, Domain domain)
       {
-	int n = (int) args[0].val;
-	for (int i = 1; i < args.Length; i++)
-	  n %= (int) args[i].val;
-	return n;
+	return ((int) args[0].val % (int) args[1].val);
       }
 
-      private static object logior (MExpression[] args, Domain domain)
+      private static object logior (Xex[] args, Domain domain)
       {
 	int n = 0;
-	foreach (MExpression e in args)
+	foreach (Xex e in args)
 	  n |= (int) e.val;
 	return n;
       }
 
-      private static object logand (MExpression[] args, Domain domain)
+      private static object logand (Xex[] args, Domain domain)
       {
-	int n = 0;
-	foreach (MExpression e in args)
-	  n &= (int) e.val;
+	int n = (int) args[0].val;
+	for (int i = 1; i < args.Length; i++)
+	  n &= (int) args[i].val;
 	return n;
       }
 
-      private static object pluseq (MExpression[] args, Domain domain)
+      private static object add_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	object val = domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
-	if (val is int)
-	  {
-	    int n = (int) val;
-	    for (int i = 1; i < args.Length; i++)
-	      n += (int) args[i].Eval (domain);
-	    val = n;
-	  }
-	else if (val is MText)
-	  {
-	    MText mt = (MText) val;
-	    for (int i = 1; i < args.Length; i++)
-	      mt.Cat ((MText) args[i].Eval (domain));
-	    val = mt;
-	  }
-	domain.SetValue (sym, val);
-	return val;
+	for (int i = 1; i < args.Length; i++)
+	  n += (int) args[i].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object multieq (MExpression[] args, Domain domain)
+      private static object mul_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	int n = (int) domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
 	for (int i = 1; i < args.Length; i++)
-	  n *= (int) args[i].Eval (domain);
-	return domain.SetValue (sym, (object) n);
+	  n *= (int) args[i].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object minuseq (MExpression[] args, Domain domain)
+      private static object sub_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	int n = (int) domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
 	for (int i = 1; i < args.Length; i++)
-	  n -= (int) args[i].Eval (domain);
-	return domain.SetValue (sym, (object) n);
+	  n -= (int) args[i].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object divideeq (MExpression[] args, Domain domain)
+      private static object div_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	int n = (int) domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
 	for (int i = 1; i < args.Length; i++)
-	  n /= (int) args[i].Eval (domain);
-	return domain.SetValue (sym, (object) n);
+	  n /= (int) args[i].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object percenteq (MExpression[] args, Domain domain)
+      private static object mod_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	int n = (int) domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
 	for (int i = 1; i < args.Length; i++)
-	  n %= (int) args[i].Eval (domain);
-	return domain.SetValue (sym, (object) n);
+	  n %= (int) args[i].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object logioreq (MExpression[] args, Domain domain)
+      private static object logior_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	int n = (int) domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
 	for (int i = 1; i < args.Length; i++)
-	  n |= (int) args[i].Eval (domain);
-	return domain.SetValue (sym, (object) n);
+	  n |= (int) args[i].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object logandeq (MExpression[] args, Domain domain)
+      private static object logand_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	int n = (int) domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
 	for (int i = 1; i < args.Length; i++)
-	  n &= (int) args[i].Eval (domain);
-	return domain.SetValue (sym, (object) n);
+	  n &= (int) args[i].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object lshift (MExpression[] args, Domain domain)
+      private static object lsh (Xex[] args, Domain domain)
       {
 	return (int) args[0].val << (int) args[1].val;
       }
 
-      private static object lshifteq (MExpression[] args, Domain domain)
+      private static object lsh_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	int n = (int) domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
-	n <<= (int) args[1].Eval (domain);
-	return domain.SetValue (sym, (object) n);
+	n <<= (int) args[1].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object rshift (MExpression[] args, Domain domain)
+      private static object rsh (Xex[] args, Domain domain)
       {
 	return (int) args[0].val >> (int) args[1].val;
       }
 
-      private static object rshifteq (MExpression[] args, Domain domain)
+      private static object rsh_set (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
-	int n = (int) domain.GetValue (sym);
+	Variable vari = domain.GetVar (args[0]);
+	int n = (int) vari.val;
 
-	n >>= (int) args[1].Eval (domain);
-	return domain.SetValue (sym, (object) n);
+	n >>= (int) args[1].val;
+	vari.val = n;
+	return n;
       }
 
-      private static object eq (MExpression[] args, Domain domain)
+      private static object eq (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 
@@ -652,12 +859,12 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object noteq (MExpression[] args, Domain domain)
+      private static object noteq (Xex[] args, Domain domain)
       {
 	return ((int) args[0].val != (int) args[1].val);
       }
 
-      private static object less (MExpression[] args, Domain domain)
+      private static object less_than (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 
@@ -671,7 +878,7 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object lesseq (MExpression[] args, Domain domain)
+      private static object less_eq (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -684,7 +891,7 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object more (MExpression[] args, Domain domain)
+      private static object greater_than (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -697,7 +904,7 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object moreeq (MExpression[] args, Domain domain)
+      private static object greater_eq (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -710,188 +917,295 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object progn (MExpression[] args, Domain domain)
+      private static object progn_clause (Xex[] args, Domain domain)
       {
-	object result = false;
+	object result = true;
 
-	foreach (MExpression e in args)
+	foreach (Xex e in args)
 	  result = e.Eval (domain);
 	return result;
       }
 
-      private static bool check_condition (MExpression condition, Domain domain)
+      private static object if_clause (Xex[] args, Domain domain)
       {
-	object result = condition.Eval (domain);
-	return (result is bool ? (bool) result
-		: result is int ? ((int) result) != 0
-		: true);
-      }
-
-      private static object ifclause (MExpression[] args, Domain domain)
-      {
-	object result = false;
+	object result;
 
-	if (check_condition (args[0], domain))
+	if (is_true (args[0].Eval (domain)))
 	  result = args[1].Eval (domain);
 	else
-	  for (int i = 2; i < args.Length; i++)
-	    result = args[i].Eval (domain);
+	  {
+	    result = false;
+	    for (int i = 2; i < args.Length; i++)
+	      result = args[i].Eval (domain);
+	  }
 	return result;
       }
 
-      private static object whenclause (MExpression[] args, Domain domain)
+      private static object when_clause (Xex[] args, Domain domain)
       {
-	object result = false;
+	if (! is_true (args[0].Eval (domain)))
+	  return false;
 
-	if (check_condition (args[0], domain))
-	  for (int i = 1; i < args.Length; i++)
-	    result = args[i].Eval (domain);
+	object result = true;
+	for (int i = 1; i < args.Length; i++)
+	  result = args[i].Eval (domain);
 	return result;
       }
 
-      private static object whileclause (MExpression[] args, Domain domain)
+      private static object while_clause (Xex[] args, Domain domain)
       {
-	while (check_condition (args[0], domain))
+	while (is_true (args[0].Eval (domain)))
 	  for (int i = 1; i < args.Length; i++)
 	    args[i].Eval (domain);
 	return false;
       }
 
-    // (cond (COND1 ...) (COND2 ...) ...)
-    //   => (cond (when COND1 ...) (when COND2 ...) ...)
-    private static void translate_cond (MPlist plist, Domain domain)
-    {
-      if (plist.IsPlist)
-	{
-	  plist = plist.Plist;
-	  if (plist.IsSymbol && plist.Symbol == Mcond)
-	    {
-	      plist.val = Mprogn;
-	      for (plist = plist.next; ! plist.IsEmpty; plist = plist.next)
-		{
-		  if (! plist.IsPlist)
-		    throw new Exception ("Invalid cond form: " + plist);
-		  plist.Plist.Push (MSymbol.symbol, Mwhen);
-		}		
-	    }
-	}
-    }
+    // FUNCALL: function != null
+    // VARREF:  function == null, args[0] = DIRECT-SYMBOL
+    // DIRECT:  function == null, args == null
 
     private Function function;
-    private MExpression[] args;
+    private Xex[] args;
     private object val;
 
-    public MExpression[] Args { get { return args; } }
+    public Xex[] Args { get { return args; } }
     public object Val { get { return val; } }
 
-    private MExpression (object val)
+    private Xex () { }
+
+    private Xex (object val)
     {
       this.val = val;
     }
 
-    // EXPR = SYMBOL | MTEXT | INTEGER | FUNCALL | PROGN
-    // FUNCALL = '(' SYMBOL EXPR* ')'
-    // PROGN = '(' EXPR * ')'
-    private MExpression (MSymbol key, object val, Domain domain)
+    private static Xex macro_expand (Xex[] bindings, Name[] args, Xex e)
     {
-      if (key == MSymbol.symbol)
+      Xex xex;
+
+      if (e.function != null)
 	{
-	  function = Function.varref;
-	  args = new MExpression[1];
-	  args[0] = new MExpression (val);
+	  xex = new Xex ();
+	  xex.function = e.function;
+	  xex.args = new Xex[e.args.Length];
+	  for (int i = e.args.Length - 1; i >= 0; i--)
+	    xex.args[i] = macro_expand (bindings, args, e.args[i]);
 	}
-      else if (key == MSymbol.integer
-	       || key == MSymbol.mtext)
+      else if (e.args != null)
 	{
-	  this.val = val;
+	  xex = new Xex ();
+	  Name name = (Name) e.args[0].val;
+	  for (int i = args.Length - 1; i >= 0; i--)
+	    if (args[i] == name)
+	      return bindings[i];
+	  xex.function = null;
+	  xex.args = new Xex[1];
+	  xex.args[0] = e.args[0];
 	}
-      else if (key == MSymbol.plist)
+      else
 	{
-	  MPlist p = (MPlist) val;
+	  xex = e;
+	}
+      return xex;
+    }
+
+    internal static int parse_integer (string str)
+    {
+      int len = str.Length;
+      bool negative = false;
+
+      if (len <= 1)
+	return (len == 0 ? 0 : str[0] - '0');
+
+      int c = str[0];
+      int i;
 
-	  if (p.IsSymbol)
+      if (c == '0' && str[1] == 'x')
+	{
+	  i = 0;
+	  for (int idx = 2; idx < len; idx++)
 	    {
-	      MSymbol sym = p.Symbol;
-
-	      if (sym == Mdefun)
-		{
-		  p = p.next;
-		  if (! p.IsSymbol)
-		    throw new Exception ("Invalid function argument: "
-					 + p.val);
-		  sym = p.Symbol;
-		  p = p.next;
-		  if (! p.IsPlist)
-		    throw new Exception ("Invalid function argument: "
-					 + p.val);
-		  domain.Defun (sym, p.Plist, p.next);
-		  // This Mexpression is just a dummy.
-		}
+	      c = str[idx];
+	      if (c < '0')
+		break;
+	      else if (c <= '9')
+		i = i * 16 + (c - '0');
+	      else if (c < 'A')
+		break;
+	      else if (c <= 'F')
+		i = i * 16 + (c - 'A');
+	      else if (c < 'a')
+		break;
+	      else if (c <= 'f')
+		i = i * 16 + (c - 'a');
 	      else
-		{
-		  function = domain.GetFunc (sym);
-		  p = p.next;
-		  int nargs = p.Count;
-		  if (nargs < function.min_arg
-		      || (function.max_arg >= 0 && nargs > function.max_arg))
-		    throw new Exception ("Invalid number of arguments to: "
-					 + sym + " " + nargs);
-		  args = new MExpression[nargs];
-		  for (int i = 0; i < nargs; i++, p = p.next)
-		    {
-		      domain.Translate (p);
-		      args[i] = new MExpression (p.key, p.val, domain);
-		    }
-		}
+		break;
 	    }
-	  else
+	  return i;
+	}
+      if (c == '-')
+	negative = true;
+      i = c - '0';
+      for (int idx = 1; idx < len; idx++)
+	{
+	  c = str[idx];
+	  if (c < '0' || c > '9')
+	    break;
+	  i = i * 10 + (c - '0');
+	}
+      return negative ? - i : i;
+    }
+
+    private int pre_parse (XmlNodeList nlist, Domain domain)
+    {
+      int len = 0;
+      foreach (XmlNode node in nlist)
+	{
+	  if (node.Name == Ndefun)
 	    {
-	      args = new MExpression[1];
-	      args[0] = new MExpression (p, domain);
+	      XmlNode n = node.FirstChild;
+	      domain.Defun ((Name) node.Attributes[0].Value,
+			    n.Name == Nargs ?  n.ChildNodes.Count : 0, false);
 	    }
+	  else if (node.Name == Ndefmacro)
+	    {
+	      XmlNode n = node.FirstChild;
+	      domain.Defun ((Name) node.Attributes[0].Value,
+			    n.Name == Nargs ?  n.ChildNodes.Count : 0, true);
+	    }
+	  else if (node.Name == Ndefvar)
+	    {
+	      domain.Defvar ((Name) node.Attributes[0].Value, node.FirstChild);
+	    }
+	  else
+	    len++;
 	}
-      else
-	throw new Exception ("Invalid expression: " + key + ":" + val);
+      return len;
     }
 
-    public MExpression (MPlist plist, Domain domain)
+    private void post_parse (XmlNodeList nlist, Domain domain)
     {
-      function = Function.block;
-      args = new MExpression[plist.Count];
-      for (int i = 0; ! plist.IsEmpty; i++, plist = plist.next)
+      for (int i = 0, j = 0; i < nlist.Count; i++)
 	{
-	  domain.Translate (plist);
-	  args[i] = new MExpression (plist.key, plist.val, domain);
+	  XmlNode node = nlist[i];
+
+	  if (node.Name == Ndefun)
+	    domain.Defun (node);
+	  else if (node.Name == Ndefmacro)
+	    domain.Defun (node);
+	  else if (node.Name != Ndefvar)
+	    args[j++] = new Xex (node, domain);
 	}
     }
 
-    public MExpression (XmlNode node, Domain domain)
+    private void Setup (XmlNode node, Domain domain)
     {
-      MSymbol sym = node.Name;
+      Name name = node.Name;
 
-      function = domain.GetFunc (sym);
+      if (name == Nconst)
+	{
+	  Name type = node.Attributes[Ntype].Value;
+
+	  if (type == Ninteger)
+	    val = parse_integer (node.InnerText);
+	  else if (type == Nstring)
+	    val = node.InnerText;
+	  else if (type == Nsymbol)
+	    val = (Name) node.InnerText;
+	  else if (type == Nboolean)
+	    val = node.InnerText == "true";
+	  else if (type == Nlist)
+	    {
+	      List<Xex> list = new List<Xex> ();
+	      for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
+		list.Add (new Xex (n, domain));
+	      val = list;
+	    }
+	  else
+	    throw new Exception ("Unknown type: " + type);
+	}
+      else if (name == Nvariable)
+	{
+	  args = new Xex[1];
+	  args[0] = new Xex ((Name) node.Attributes[0].Value);
+	}
+      else
+	{
+	  bool is_macro = false;
 
-      XmlAttributeCollection attrs = node.Attributes;
+	  if (name == Nfuncall)
+	    {
+	      name = node.Attributes[0].Value;
+	      if (Nmname == node.Attributes[0].Name)
+		is_macro = true;
+	    }
 
-      int nargs = attrs.Count + node.ChildNodes.Count;
-      if (nargs < function.min_arg
-	  || (function.max_arg >= 0 && nargs > function.max_arg))
-	throw new Exception ("Invalid number of arguments: " + node.InnerXml);
-      args = new MExpression[nargs];
-      int i;
-      for (i = 0; i < attrs.Count; i++)
-	{
-	  string str = sttrs[i].Value;
+	  function = domain.GetFunc (name);
+
+	  XmlNodeList nlist = node.ChildNodes;
+	  int nargs = nlist.Count;
+
+	  if (nargs < function.min_arg
+	      || (function.max_arg >= 0 && nargs > function.max_arg))
+	    throw new Exception ("Invalid number of arguments to: "
+				 + name + " " + nargs);
+	  nargs =  pre_parse (nlist, domain);
+	  args = new Xex[nargs];
+	  post_parse (nlist, domain);
+
+	  if (is_macro)
+	    {
+	      Function.Lambda lambda = function.lambda;
+	      Xex[] body = lambda.body;
+	      int len = body.Length;
+	      Xex[] newargs = new Xex[len];
+
+	      for (int i = 0; i < len; i++)
+		newargs[i] = macro_expand (args, lambda.args, body[i]);
+	      function = Fprogn;
+	      args = newargs;
+	    }
+	}
+    }
+
+    public Xex (string url, Domain domain)
+    {
+      XmlDocument doc = new XmlDocument (Name.Table);
+      XmlNode node;
 
+      using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
+	{
+	  do {
+	    reader.Read ();
+	  } while (reader.NodeType != XmlNodeType.None
+		   && (reader.NodeType != XmlNodeType.Element
+			|| Nexpr != reader.Name));
+	  if (reader.NodeType == XmlNodeType.None)
+	    throw new Exception ("Node <expr> not found");
+	  node = doc.ReadNode (reader);
 	}
+
+      Setup (node, domain);
+    }
+
+
+    // EXPR = SYMBOL | MTEXT | INTEGER | FUNCALL | PROGN
+    // FUNCALL = '(' SYMBOL EXPR* ')'
+    // PROGN = '(' EXPR * ')'
+    public Xex (XmlNode node, Domain domain)
+    {
+      Setup (node, domain);
     }
 
     public object Eval (Domain domain)
     {
       if (function == null)
 	{
-	  if (val is MSymbol)
-	    val = domain.GetValue ((MSymbol) val);
+	  if (args != null)
+	    {
+	      Variable vari = domain.GetVar ((Name) args[0].val);
+	      val = vari.val;
+	    }
+	  return val;
 	}
       else
 	val = function.Call (args, domain);
@@ -904,16 +1218,20 @@ public class XmlName : IEquatable<XmlName>
 
       if (function != null)
 	{
-	  str = "(" + function.Name.Name;
+	  str = "(" + function.name;
 	  if (args != null)
-	    foreach (MExpression e in args)
+	    foreach (Xex e in args)
 	      str += " " + e.ToString ();
 	  str += ")";
 	}
+      else if (args != null)
+	{
+	  str = (Name) args[0].val;
+	}
       else if (val != null)
 	{
-	  if (val is MText)
-	    str = "\"" + (string) ((MText) val) + "\"";
+	  if (val is string)
+	    str = "\"" + ((string) val) + "\"";
 	  else
 	    str = val.ToString ();
 	}