From: handa <handa>
Date: Fri, 11 Sep 2009 00:08:23 +0000 (+0000)
Subject: *** empty log message ***
X-Git-Url: http://git.chise.org/gitweb/?a=commitdiff_plain;h=6117466b13d62831e1c3a53bfdae0aab8afb1c3e;p=m17n%2Fm17n-lib-cs.git

*** empty log message ***
---

diff --git a/XmlExpr.cs b/XmlExpr.cs
index ba46189..d37fc40 100644
--- a/XmlExpr.cs
+++ b/XmlExpr.cs
@@ -6,72 +6,120 @@ using System.Xml;
 
 namespace System.Xml.Expression
 {
-public class XmlName : IEquatable<XmlName>
+  public class Xex
   {
-    private static NameTable nt = new NameTable ();
+    public class Name : IEquatable<Name>
+    {
+      private static NameTable nt = new NameTable ();
+
+      private object name;
+
+      private Name (string str)
+	{
+	  name = nt.Add (str);
+	}
+
+      private Name (XmlAttribute attr)
+	{
+	  name = attr.Value;
+	}
 
-    private object name;
+      private Name (XmlNode node)
+	{
+	  name = node.Name;
+	}
 
-    private XmlName (string 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 bool operator== (XmlName n1, XmlName n2)
+      public static implicit operator string (Name name)
       {
-	return n1.name == n2.name;
+	return (string) name.name;
       }
 
-    public static bool operator!= (XmlName n1, XmlName n2)
+      public static bool operator== (Name n1, Name n2)
+	{
+	  return n1.name == n2.name;
+	}
+
+      public static bool operator!= (Name n1, Name n2)
+	{
+	  return n1.name != n2.name;
+	}
+
+      public bool Equals (Name other) { return name == other.name; }
+      public override bool Equals (object obj) { return obj == name; }
+      public override int GetHashCode ()
       {
-	return n1.name != n2.name;
+	return ((string) name).GetHashCode ();
       }
 
-    public bool Equals (XmlName other) { return name == other.name; }
-    public override bool Equals (object obj) { return obj == name; }
-    public override int GetHashCode ()
-    {
-      return ((string) name).GetHashCode ();
+      public static NameTable Table { get { return nt; } }
     }
 
-    public static NameTable Table { get { return nt; } }
-  }
-
-  public class Xex
-  {
-    private static NameTable nt = new NameTable ();
+    private static Name Nvalue = "value";
+    private static Name Nvar = "var";
+    private static Name Ndefun = "defun";
+    private static Name Ncond = "cond";
+    private static Name Nprogn = "progn";
+    private static Name Nwhen = "when";
 
-    public static object Name (string str)
+    public class Bindings
     {
-      return nt.Add (str);
-    }
+      private Name name;
+      private object value;
+      private Bindings next;
+	
+      internal Bindings (Name name, object value)
+      {
+	this.name = name;
+	this.value = value;
+      }
+	
+      internal Bindings ()
+      {
+      }
+	
+      internal Bindings Bind (Name name, object value)
+      {
+	Bindings bindings = new Bindings (name, value);
+	bindings.next = this;
+	return bindings;
+      }
 
-    public static NameTable Table { get { return nt; } }
+      internal Bindings SetBoundary ()
+      {
+	Bindings bindings = new Bindings ();
+	bindings.next = this;
+	return this;
+      }
 
-    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");
+      internal Bindings Pop ()
+      {
+	return bindings.next;
+      }
+
+      public override string ToString ()
+      {
+	string str = "(bindings";
+	for (Bindings b = this; b != null; b = b.next)
+	  str += " " + name + ":" + value;
+	return str + ")";
+      }
+    }
 
     public class Domain
     {
       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;
 
-      internal Domain ()
-      {
-	boundaries.Push (bindings);
-      }
+      internal Dictionary<Name, Function> functions
+	= new Dictionary<Name, Function> ();
+      private Bindings bindings;
+
+      internal Domain () { }
 
       public Domain (object context) : this (basic, context) { }
 
@@ -79,47 +127,39 @@ public class XmlName : IEquatable<XmlName>
       {
 	this.parent = parent;
 	this.context = context;
-	boundaries.Push (bindings);
       }
 
-      public void AddTranslator (Translator translator)
+      public void Bind (Name name, object value)
       {
-	if (this.translator == null)
-	  this.translator = translator;
+	if (bindings == null)
+	  bindings = new Bindings (name, value);
 	else
-	  this.translator += translator;
+	  bindings = bindings.Bind (name, value);
       }
 
-      public void Bind (MSymbol sym, object value)
-      {
-	bindings = bindings.Cons (sym, value);
-      }
-
-      public MPlist SetBoundary ()
+      public Bindings SetBoundary ()
       {
 	boundaries.Push (bindings);
 	return bindings;
       }
 
-      public void UnboundTo (MPlist boundary)
+      public void UnboundTo (Bindings boundary)
       {
 	while (boundary != boundaries.Pop ());
-	while (bindings != boundary)
-	  bindings = bindings.next;
+	while (bindings.Pop != 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: "
@@ -132,39 +172,17 @@ 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)
-      {
-	Function func = (Function) functions.Get (sym);
-
-	if (func != null)
-	  {
-	    int nargs = args == null ? 0 : args.Count;
-
-	    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);
-	    func.builtin = null;
-	  }
-	else
-	  {
-	    func = new Function (sym, args, body, this);
-	    functions = functions.Cons (sym, func);
-	  }	    
-      }
-
       public void Defun (XmlNode node)
       {
-	MSymbol sym = node.Attributes["id"].Value;
-	Function func = (Function) functions.Get (sym);
+	Name name = node.Attributes["id"];
+	Function func;
 
-	if (func != null)
+	if (functions.TryGetValue (name, out func))
 	  {
 	    XmlNode args = node.FirstChild;
 	    int nargs = args.Name == "args" ? args.ChildNodes.Count : 0;
@@ -182,7 +200,7 @@ public class XmlName : IEquatable<XmlName>
 	  }	    
       }
 
-      internal Function GetFunc (MSymbol name)
+      internal Function GetFunc (Name name)
       {
 	Function func = (Function) functions.Get (name);
 
@@ -195,7 +213,7 @@ 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)
@@ -210,7 +228,7 @@ public class XmlName : IEquatable<XmlName>
 	  domain.functions = domain.functions.Cons (p.key, p.val);
       }
 
-      public object GetValue (MSymbol name)
+      public object GetValue (Name name)
       {
 	MPlist slot = bindings.Find (name);
 
@@ -223,7 +241,7 @@ public class XmlName : IEquatable<XmlName>
 	return slot.val;
       }
 
-      public object SetValue (MSymbol name, object val)
+      public object SetValue (Name name, object val)
       {
 	MPlist boundary = boundaries.Peek ();
 
@@ -237,26 +255,17 @@ public class XmlName : IEquatable<XmlName>
 	return val;
       }
 
-      public bool IsBound (MSymbol name)
+      public bool IsBound (Name name)
       {
 	return (bindings.Find (name) != null);
       }
 
-      public void Translate (MPlist plist)
-      {
-	if (parent != null)
-	  parent.Translate (plist);
-	if (translator != null)
-	  for (MPlist p = plist; ! p.IsEmpty; p = p.next)
-	    translator (p, this);
-      }
-
       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 += ") " + bindings;
 	if (context != null)
 	  str += " (" + context + ")";
 	str += ">";
@@ -264,49 +273,20 @@ 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;
-
-	public Lambda (MPlist args, MPlist body, Domain domain)
-	{
-	  SetArgs (args);
-	  SetBody (body, domain);
-	}
+	internal Name[] args;
+	internal Xex[] body;
 
 	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;
@@ -316,21 +296,21 @@ public class XmlName : IEquatable<XmlName>
 	    {
 	      XmlNodeList args = body[0].ChildNodes;
 	      if (this.args == null)
-		this.args = new MSymbol[args.Count];
+		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 MSymbol[0];
+	    this.args = new Name[0];
 	  if (this.body == null)
-	    this.body = new MExpression[body.Count - idx];
+	    this.body = new Xex[body.Count - idx];
 	  for (int i = 0; idx < body.Count; i++, idx++)
-	    this.body[i] = new MExpression (body[idx], domain);
+	    this.body[i] = new Xex (body[idx], domain);
 	}
       }
 
-      public readonly MSymbol Name;
+      public readonly Name Name;
       public Builtin builtin;
       public int min_arg, max_arg;
       internal Lambda lambda;
@@ -338,7 +318,7 @@ public class XmlName : IEquatable<XmlName>
 
       internal static Function ignore, varref, block;
 
-      public Function (MSymbol name, Builtin builtin,
+      public Function (Name name, Builtin builtin,
 		       int min_arg, int max_arg, bool specialp)
       {
 	Name = name;
@@ -348,15 +328,7 @@ public class XmlName : IEquatable<XmlName>
 	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)
+      internal Function (Name name, XmlNode node, Domain domain)
       {
 	Name = name;
 	lambda = new Lambda (node, domain);
@@ -365,7 +337,7 @@ public class XmlName : IEquatable<XmlName>
 
       private Function ()
       {
-	Name = MSymbol.nil;
+	Name = Name.nil;
       }
 
       static Function ()
@@ -375,29 +347,29 @@ public class XmlName : IEquatable<XmlName>
 	block = new Function (Mprogn, progn, 0, -1, true);
       }
 
-      private static object get_value (MExpression[] args, Domain domain)
+      private static object get_value (Xex[] args, Domain domain)
       {
-	return domain.GetValue ((MSymbol) args[0].val);
+	return domain.GetValue ((Name) args[0].val);
       }
 
-      public object Call (MExpression[] args, Domain domain)
+      public object Call (Xex[] args, Domain domain)
       {
 	if (builtin != null)
 	  {
 	    if (! specialp)
-	      foreach (MExpression e in args)
+	      foreach (Xex e in args)
 		e.Eval (domain);
 	    return builtin (args, domain);
 	  }
 	if (lambda == null)
 	  return null;
-	MPlist orig_bindings = domain.bindings;
+	Bindings orig_bindings = domain.bindings;
 	object result = false;
 	try {
 	  int i = 0;
-	  foreach (MSymbol arg in lambda.args)
+	  foreach (Name arg in lambda.args)
 	    domain.Bind (arg, args[i++].Eval (domain));
-	  foreach (MExpression e in lambda.body)
+	  foreach (Xex e in lambda.body)
 	    result = e.Eval (domain);
 	} finally {
 	  domain.bindings = orig_bindings;
@@ -408,7 +380,7 @@ public class XmlName : IEquatable<XmlName>
 
     private static Domain basic;
 
-    static MExpression ()
+    static Xex ()
     {
       basic = new Domain ();
 
@@ -447,13 +419,13 @@ public class XmlName : IEquatable<XmlName>
       basic.AddTranslator (new Translator (translate_cond));
     }
 
-    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,
+      return domain.SetValue ((Name) args[0].args[0].val,
 			      args[1].Eval (domain));
     }
 
-    private static object not (MExpression[] args, Domain domain)
+    private static object not (Xex[] args, Domain domain)
     {
       if (args[0].val is int)
 	return (int) args[0].val == 0;
@@ -462,34 +434,34 @@ public class XmlName : IEquatable<XmlName>
       return true;
     }
 
-    private static object plus (MExpression[] args, Domain domain)
+    private static object plus (Xex[] args, Domain domain)
     {
       if (args[0].val is int)
 	{
 	  int n = 0;
-	  foreach (MExpression e in args)
+	  foreach (Xex 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)
+	  foreach (Xex e in args)
 	    mt += (MText) e.val;
 	  return mt;
 	}
       throw new Exception ("Not an integer nor MText: " + args[0].val);
     }
 
-      private static object multi (MExpression[] args, Domain domain)
+      private static object multi (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 minus (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	if (args.Length == 1)
@@ -499,7 +471,7 @@ public class XmlName : IEquatable<XmlName>
 	return n;
       }
 
-      private static object divide (MExpression[] args, Domain domain)
+      private static object divide (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -507,7 +479,7 @@ public class XmlName : IEquatable<XmlName>
 	return n;
       }
 
-      private static object percent (MExpression[] args, Domain domain)
+      private static object percent (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -515,25 +487,25 @@ public class XmlName : IEquatable<XmlName>
 	return n;
       }
 
-      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)
+	foreach (Xex e in args)
 	  n &= (int) e.val;
 	return n;
       }
 
-      private static object pluseq (MExpression[] args, Domain domain)
+      private static object pluseq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	object val = domain.GetValue (sym);
 
 	if (val is int)
@@ -554,9 +526,9 @@ public class XmlName : IEquatable<XmlName>
 	return val;
       }
 
-      private static object multieq (MExpression[] args, Domain domain)
+      private static object multieq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	int n = (int) domain.GetValue (sym);
 
 	for (int i = 1; i < args.Length; i++)
@@ -564,9 +536,9 @@ public class XmlName : IEquatable<XmlName>
 	return domain.SetValue (sym, (object) n);
       }
 
-      private static object minuseq (MExpression[] args, Domain domain)
+      private static object minuseq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	int n = (int) domain.GetValue (sym);
 
 	for (int i = 1; i < args.Length; i++)
@@ -574,9 +546,9 @@ public class XmlName : IEquatable<XmlName>
 	return domain.SetValue (sym, (object) n);
       }
 
-      private static object divideeq (MExpression[] args, Domain domain)
+      private static object divideeq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	int n = (int) domain.GetValue (sym);
 
 	for (int i = 1; i < args.Length; i++)
@@ -584,9 +556,9 @@ public class XmlName : IEquatable<XmlName>
 	return domain.SetValue (sym, (object) n);
       }
 
-      private static object percenteq (MExpression[] args, Domain domain)
+      private static object percenteq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	int n = (int) domain.GetValue (sym);
 
 	for (int i = 1; i < args.Length; i++)
@@ -594,9 +566,9 @@ public class XmlName : IEquatable<XmlName>
 	return domain.SetValue (sym, (object) n);
       }
 
-      private static object logioreq (MExpression[] args, Domain domain)
+      private static object logioreq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	int n = (int) domain.GetValue (sym);
 
 	for (int i = 1; i < args.Length; i++)
@@ -604,9 +576,9 @@ public class XmlName : IEquatable<XmlName>
 	return domain.SetValue (sym, (object) n);
       }
 
-      private static object logandeq (MExpression[] args, Domain domain)
+      private static object logandeq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	int n = (int) domain.GetValue (sym);
 
 	for (int i = 1; i < args.Length; i++)
@@ -614,35 +586,35 @@ public class XmlName : IEquatable<XmlName>
 	return domain.SetValue (sym, (object) n);
       }
 
-      private static object lshift (MExpression[] args, Domain domain)
+      private static object lshift (Xex[] args, Domain domain)
       {
 	return (int) args[0].val << (int) args[1].val;
       }
 
-      private static object lshifteq (MExpression[] args, Domain domain)
+      private static object lshifteq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	int n = (int) domain.GetValue (sym);
 
 	n <<= (int) args[1].Eval (domain);
 	return domain.SetValue (sym, (object) n);
       }
 
-      private static object rshift (MExpression[] args, Domain domain)
+      private static object rshift (Xex[] args, Domain domain)
       {
 	return (int) args[0].val >> (int) args[1].val;
       }
 
-      private static object rshifteq (MExpression[] args, Domain domain)
+      private static object rshifteq (Xex[] args, Domain domain)
       {
-	MSymbol sym = (MSymbol) args[0].args[0].val;
+	Name sym = (Name) args[0].args[0].val;
 	int n = (int) domain.GetValue (sym);
 
 	n >>= (int) args[1].Eval (domain);
 	return domain.SetValue (sym, (object) 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 +624,12 @@ 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 (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 
@@ -671,7 +643,7 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object lesseq (MExpression[] args, Domain domain)
+      private static object lesseq (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -684,7 +656,7 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object more (MExpression[] args, Domain domain)
+      private static object more (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -697,7 +669,7 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object moreeq (MExpression[] args, Domain domain)
+      private static object moreeq (Xex[] args, Domain domain)
       {
 	int n = (int) args[0].val;
 	for (int i = 1; i < args.Length; i++)
@@ -710,16 +682,16 @@ public class XmlName : IEquatable<XmlName>
 	return true;
       }
 
-      private static object progn (MExpression[] args, Domain domain)
+      private static object progn (Xex[] args, Domain domain)
       {
 	object result = false;
 
-	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 bool check_condition (Xex condition, Domain domain)
       {
 	object result = condition.Eval (domain);
 	return (result is bool ? (bool) result
@@ -727,7 +699,7 @@ public class XmlName : IEquatable<XmlName>
 		: true);
       }
 
-      private static object ifclause (MExpression[] args, Domain domain)
+      private static object ifclause (Xex[] args, Domain domain)
       {
 	object result = false;
 
@@ -739,7 +711,7 @@ public class XmlName : IEquatable<XmlName>
 	return result;
       }
 
-      private static object whenclause (MExpression[] args, Domain domain)
+      private static object whenclause (Xex[] args, Domain domain)
       {
 	object result = false;
 
@@ -749,7 +721,7 @@ public class XmlName : IEquatable<XmlName>
 	return result;
       }
 
-      private static object whileclause (MExpression[] args, Domain domain)
+      private static object whileclause (Xex[] args, Domain domain)
       {
 	while (check_condition (args[0], domain))
 	  for (int i = 1; i < args.Length; i++)
@@ -757,34 +729,18 @@ public class XmlName : IEquatable<XmlName>
 	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 (object val)
     {
       this.val = val;
     }
@@ -792,26 +748,48 @@ public class XmlName : IEquatable<XmlName>
     // EXPR = SYMBOL | MTEXT | INTEGER | FUNCALL | PROGN
     // FUNCALL = '(' SYMBOL EXPR* ')'
     // PROGN = '(' EXPR * ')'
-    private MExpression (MSymbol key, object val, Domain domain)
+    private Xex (XmlNode node, Domain domain)
     {
-      if (key == MSymbol.symbol)
+      object name = node.Name;
+
+      if (name == Nvalue)
 	{
-	  function = Function.varref;
-	  args = new MExpression[1];
-	  args[0] = new MExpression (val);
+	  object type = node.Attributes["type"];
+
+	  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 (key == MSymbol.integer
-	       || key == MSymbol.mtext)
+      else if (name = Nval)
 	{
-	  this.val = val;
+	  name = name.Attributes[];
+
+	  args = new Xex[1];
+	  args[0] = new Xex (
+
+
 	}
-      else if (key == MSymbol.plist)
+      else if (key == Name.plist)
 	{
 	  MPlist p = (MPlist) val;
 
 	  if (p.IsSymbol)
 	    {
-	      MSymbol sym = p.Symbol;
+	      Name sym = p.Symbol;
 
 	      if (sym == Mdefun)
 		{
@@ -825,7 +803,7 @@ public class XmlName : IEquatable<XmlName>
 		    throw new Exception ("Invalid function argument: "
 					 + p.val);
 		  domain.Defun (sym, p.Plist, p.next);
-		  // This Mexpression is just a dummy.
+		  // This Xex is just a dummy.
 		}
 	      else
 		{
@@ -836,38 +814,27 @@ public class XmlName : IEquatable<XmlName>
 		      || (function.max_arg >= 0 && nargs > function.max_arg))
 		    throw new Exception ("Invalid number of arguments to: "
 					 + sym + " " + nargs);
-		  args = new MExpression[nargs];
+		  args = new Xex[nargs];
 		  for (int i = 0; i < nargs; i++, p = p.next)
 		    {
 		      domain.Translate (p);
-		      args[i] = new MExpression (p.key, p.val, domain);
+		      args[i] = new Xex (p.key, p.val, domain);
 		    }
 		}
 	    }
 	  else
 	    {
-	      args = new MExpression[1];
-	      args[0] = new MExpression (p, domain);
+	      args = new Xex[1];
+	      args[0] = new Xex (p, domain);
 	    }
 	}
       else
 	throw new Exception ("Invalid expression: " + key + ":" + val);
     }
 
-    public MExpression (MPlist plist, Domain domain)
-    {
-      function = Function.block;
-      args = new MExpression[plist.Count];
-      for (int i = 0; ! plist.IsEmpty; i++, plist = plist.next)
-	{
-	  domain.Translate (plist);
-	  args[i] = new MExpression (plist.key, plist.val, domain);
-	}
-    }
-
-    public MExpression (XmlNode node, Domain domain)
+    public Xex (XmlNode node, Domain domain)
     {
-      MSymbol sym = node.Name;
+      Name sym = node.Name;
 
       function = domain.GetFunc (sym);
 
@@ -877,11 +844,11 @@ public class XmlName : IEquatable<XmlName>
       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];
+      args = new Xex[nargs];
       int i;
       for (i = 0; i < attrs.Count; i++)
 	{
-	  string str = sttrs[i].Value;
+	  string str = attrs[i].Value;
 
 	}
     }
@@ -890,8 +857,8 @@ public class XmlName : IEquatable<XmlName>
     {
       if (function == null)
 	{
-	  if (val is MSymbol)
-	    val = domain.GetValue ((MSymbol) val);
+	  if (val is Name)
+	    val = domain.GetValue ((Name) val);
 	}
       else
 	val = function.Call (args, domain);
@@ -906,7 +873,7 @@ public class XmlName : IEquatable<XmlName>
 	{
 	  str = "(" + function.Name.Name;
 	  if (args != null)
-	    foreach (MExpression e in args)
+	    foreach (Xex e in args)
 	      str += " " + e.ToString ();
 	  str += ")";
 	}