2 using System.Collections;
3 using System.Collections.Generic;
5 using System.Reflection;
10 public class Xexpression
12 private static int trace_depth = 0;
14 public static int TraceDepth {
15 get { return trace_depth; }
16 set { trace_depth = value; }
19 public struct Symbol : IEquatable<Symbol>
21 private static NameTable nt = new NameTable ();
25 public Symbol (string str) { name = nt.Add (str); }
27 public static implicit operator Symbol (string str)
29 return new Symbol (str);
32 public static implicit operator string (Symbol sym) { return sym.name; }
34 public static bool operator== (Symbol n1, Symbol n2)
36 return (object) n1.name == (object) n2.name;
39 public static bool operator!= (Symbol n1, Symbol n2)
41 return (object) n1.name != (object) n2.name;
44 public static bool operator== (Symbol n1, string n2)
46 return (object) n1.name == (object) n2;
49 public static bool operator!= (Symbol n1, string n2)
51 return (object) n1.name != (object) n2;
54 public static bool operator== (string n1, Symbol n2)
56 return (object) n1 == (object) n2.name;
59 public static bool operator!= (string n1, Symbol n2)
61 return (object) n1 != (object) n2.name;
64 public bool Equals (Symbol name)
66 return Object.ReferenceEquals (this.name, name.name);
69 public override bool Equals (object obj)
71 return (obj is Symbol ? this == (Symbol) obj
72 : obj is string ? this.name == (string) obj
76 public override int GetHashCode ()
78 return name.GetHashCode ();
81 public static NameTable NameTable { get { return nt; } }
83 public override string ToString () { return name; }
86 private static Symbol Qexpr = "expr";
88 private static Symbol Qnull = "";
89 private static Symbol Qfuncall = "funcall";
90 private static Symbol Qinteger = "integer";
91 private static Symbol Qstring = "string";
92 private static Symbol Qsymbol = "symbol";
93 private static Symbol Qlist = "list";
95 public static Symbol Qdefun = "defun";
96 public static Symbol Qdefmacro = "defmacro";
97 private static Symbol Qfname = "fname";
98 private static Symbol Qargs = "args";
99 private static Symbol Qfixed = "fixed";
100 private static Symbol Qoptional = "optional";
101 private static Symbol Qrest = "rest";
103 public static Symbol Qdefvar = "defvar";
104 private static Symbol Qvname = "vname";
105 private static Symbol Qdescription = "description";
106 private static Symbol Qrange = "range";
108 private static Symbol Qename = "ename";
110 public static partial class Error
113 public static Symbol UnknownFunction = "unknown function";
114 public static Symbol InvalidArgumentNumber = "invalid argument number";
115 public static Symbol VariableNotAcceptable = "variable not acceptable";
118 public static partial class Error
121 public static Symbol ArithmeticError = "arithmetic error";
122 public static Symbol InvalidArgumentType = "invalid argument type";
123 public static Symbol NoVariable = "no-variable";
124 public static Symbol InvalidVariableType = "invalid variable type";
125 public static Symbol NoOuterLoop = "no outer loop";
126 public static Symbol UnknownError = "unknown error";
130 public abstract class Function
133 public int min_arg, max_arg;
136 public Function () { }
138 public Function (Symbol name, int min_arg, int max_arg, bool setvar)
141 this.min_arg = min_arg;
142 this.max_arg = max_arg;
143 this.setvar = setvar;
146 public abstract Term Call (Domain domain, Variable vari, Term[] args);
148 public override string ToString ()
153 internal class Subroutine : Function
155 public Builtin builtin;
157 public Subroutine (Builtin builtin, Symbol name, bool setvar,
158 int min_arg, int max_arg)
159 : base (name, min_arg, max_arg, setvar)
161 this.builtin = builtin;
164 public override Term Call (Domain domain, Variable vari, Term[] args)
168 args = (Term[]) args.Clone ();
169 for (int i = 0; i < args.Length; i++)
171 args[i] = args[i].Eval (domain);
172 if (domain.Thrown ())
176 return builtin (domain, vari, args);
180 internal class SpecialForm : Function
182 public Builtin builtin;
184 public SpecialForm (Builtin builtin, Symbol name, bool setvar,
185 int min_arg, int max_arg)
186 : base (name, min_arg, max_arg, setvar)
188 this.builtin = builtin;
191 public override Term Call (Domain domain, Variable vari, Term[] args)
193 return builtin (domain, vari, args);
197 private static void parse_head (Domain domain, XmlNode node,
199 out int min_arg, out int max_arg,
205 name = node.Attributes[Qfname].Value;
207 node = node.FirstChild;
208 if (node != null && node.Name == Qargs)
211 for (n = node.FirstChild; n != null; n = n.NextSibling)
213 if (n.Name == Qfixed)
214 nfixed += n.ChildNodes.Count;
215 else if (n.Name == Qoptional)
216 noptional += n.ChildNodes.Count;
217 else if (n.Name == Qrest)
220 throw new Exception ("Invalid argument type: " + n);
223 max_arg = nfixed + noptional + nrest;
224 args = new Variable[max_arg];
226 for (int i = 0; i < max_arg; n = n.NextSibling)
228 for (XmlNode nn = n.FirstChild; nn != null; nn = nn.NextSibling)
229 args[i++] = domain.Defvar ((Symbol) nn.Attributes[0].Value);
236 min_arg = max_arg = 0;
237 args = new Variable[0];
241 private static void parse_body (Domain domain, XmlNode node,
244 for (node = node.FirstChild; node != null; node = node.NextSibling)
245 if (node.Name != Qdescription
246 && node.Name != Qargs)
249 for (XmlNode n = node; n != null; n = n.NextSibling)
253 body = new Term[nterms];
254 for (nterms = 0; node != null; node = node.NextSibling, nterms++)
255 body[nterms] = new Term (domain, node);
261 internal class Macro : Function
263 internal Variable[] args;
264 internal Term[] body;
266 public Macro (Domain domain, XmlNode node)
268 parse_head (domain, node, out name, out min_arg, out max_arg,
273 public void SetBody (Domain domain, XmlNode node)
275 parse_body (domain, node, out body);
278 public override Term Call (Domain domain, Variable vari, Term[] args)
280 Bindings current = domain.bindings;
282 int rest_idx = max_idx < 0 ? - max_idx : args.Length;
284 for (int i = 0; i < rest_idx; i++)
285 domain.Bind (this.args[i], args[i]);
288 List<Term> rest = new List<Term> ();
290 for (; i < args.Length; i++)
292 domain.Bind (this.args[rest_idx], rest);
297 domain.Catch (CatchTag.Return);
298 foreach (Term term in body)
300 result = term.Eval (domain);
301 if (domain.Thrown ())
306 domain.UnboundTo (current);
311 internal class Lambda : Function
313 internal Variable[] args;
314 internal Term[] body;
316 public Lambda (Domain domain, XmlNode node)
318 parse_head (domain, node, out name, out min_arg, out max_arg,
323 public Lambda (Domain domain, Symbol name, Symbol[] args)
333 for (i = 0; i < args.Length; i++, nfixed++)
334 if (args[i] == Qoptional || args[i] == Qrest)
338 if (args[i] == Qoptional)
340 for (i++; i < args.Length; i++, noptional++)
341 if (args[i] == Qrest)
348 max_arg = nfixed + noptional + nrest;
349 this.args = new Variable[max_arg];
351 for (i = j = 0; j < this.args.Length; i++)
352 if (args[i] != Qoptional || args[i] != Qrest)
353 this.args[j++] = domain.Defvar (args[i]);
357 min_arg = max_arg = 0;
362 public void SetBody (Domain domain, XmlNode node)
364 parse_body (domain, node, out body);
367 public void SetBody (Term[] body)
372 public override Term Call (Domain domain, Variable vari, Term[] args)
374 Bindings current = domain.bindings;
381 Term[] newargs = new Term[args.Length];
382 for (i = 0; i < min_arg; i++)
383 newargs[i] = args[i].Eval (domain);
386 for (i = 0; i < min_arg; i++)
387 domain.Bind (this.args[i], args[i]);
391 domain.Catch (CatchTag.Return);
392 foreach (Term term in body)
394 result = term.Eval (domain);
395 if (domain.Thrown ())
403 domain.UnboundTo (current);
410 public class Variable
412 public Domain domain;
413 public readonly Symbol name;
416 public Variable (Domain domain, Symbol name, Term val)
418 this.domain = domain;
423 public virtual bool ValueP (Term val) { return true; }
425 public virtual Variable Clone (Domain domain)
427 return new Variable (domain, name, val);
430 public virtual void Reset () { val = Zero; }
436 if (! ValueP (value))
437 throw new Exception ("Invalid value: " + value);
442 public Term SetValue (int i)
449 public Term SetValue (string s)
455 public override string ToString () { return name + "(" + val + ")"; }
457 public abstract class Typed : Variable
459 protected string desc;
460 private Term default_val;
462 protected Typed (Domain domain, Symbol name, Term val, string desc)
463 : base (domain, name, val)
469 public override void Reset () { val = default_val; }
471 public string Description {
473 set { desc = value; }
477 public class Int : Typed
481 public bool IsSubrange (int[] r)
485 for (int i = 0; i < r.Length; i += 2)
488 for (j = 0; j < range.Length; j += 2)
489 if (range[j] <= r[i] && range[j + 1] >= r[i + 1])
491 if (j >= range.Length)
497 public Int (Domain domain, Symbol name, int n, string desc, int[] range)
498 : base (domain, name, new Term (n), desc)
500 if (range != null && range.Length % 2 == 1)
501 throw_exception ("Range length for {0} not even", name);
504 throw_exception ("Invalid integer value for {0}: {1}", name, val);
507 public override bool ValueP (Term term)
514 for (int i = 0; i < range.Length; i += 2)
515 if (range[i] <= n && range[i + 1] >= n)
520 public override Variable Clone (Domain domain)
522 return new Int (domain, name, val.Intval, desc, range);
525 public int[] Range { get { return range; } set { range = value; } }
528 public class Str : Typed
530 private string[] range;
532 public bool IsSubrange (string[] r)
536 for (int i = 0; i < r.Length; i++)
539 for (j = 0; j < range.Length; j++)
540 if (range[j] == r[i])
542 if (j >= range.Length)
548 public Str (Domain domain, Symbol name, string str, string desc,
550 : base (domain, name, new Term (str), desc)
554 throw_exception ("Invalid string value for {0}: {1}", name, val);
557 public override bool ValueP (Term term)
563 string str = term.Strval;
564 foreach (string s in range)
570 public override Variable Clone (Domain domain)
572 return new Str (domain, name, val.Strval, desc, range);
575 public string[] Range { get { return range; } set { range = value; } }
578 public class Sym : Typed
580 public Symbol[] range;
582 public bool IsSubrange (Symbol[] r)
586 for (int i = 0; i < r.Length; i++)
589 for (j = 0; j < range.Length; j++)
590 if (range[j] == r[i])
592 if (j >= range.Length)
598 public Sym (Domain domain, Symbol name, Symbol sym, string desc,
600 : base (domain, name, new Term (sym), desc)
604 throw_exception ("Invalid symbol value for {0}: {1}", name, val);
607 public override bool ValueP (Term term)
613 Symbol name = term.Symval;
614 foreach (Symbol n in range)
620 public override Variable Clone (Domain domain)
622 return new Sym (domain, name, val.Symval, desc, range);
625 public Symbol[] Range { get { return range; } set { range = value; } }
629 internal class Bindings
631 private Variable vari;
632 private Term old_value;
633 private Bindings next;
635 private Bindings (Variable vari)
638 old_value = vari.Value;
641 public static Bindings Bind (Bindings bindings, Variable vari, Term val)
643 Bindings b = new Bindings (vari);
650 internal Bindings UnboundTo (Bindings boundary)
652 for (Bindings b = this; b != boundary; b = b.next)
653 b.vari.Value = b.old_value;
657 public override string ToString ()
659 string str = "(bindings";
660 for (Bindings b = this; b != null; b = b.next)
661 str += " " + vari.name + "=" + b.old_value;
666 private static void throw_exception (string fmt, params object[] args)
668 throw new Exception (String.Format (fmt, args));
671 internal struct CatchTag
675 public CatchTag (Symbol sym) { tag = new Term (sym); }
676 public CatchTag (Symbol sym, string msg) { tag = new Term (sym, msg); }
677 public CatchTag (ErrorTerm e) { tag = new Term (e); }
678 private CatchTag (int i) { tag = new Term (i); }
680 public Term Tag { get { return tag; } }
682 public static CatchTag Return = new CatchTag (0);
683 public static CatchTag Break = new CatchTag (1);
689 public object context;
690 public int depth = 0;
691 private Stack<Term> call_stack = new Stack<Term> ();
693 internal Dictionary<Symbol, MethodInfo> termtypes
694 = new Dictionary<Symbol, MethodInfo> ();
695 internal Dictionary<Symbol, Function> functions
696 = new Dictionary<Symbol, Function> ();
697 internal Dictionary<Symbol, Variable> variables
698 = new Dictionary<Symbol, Variable> ();
699 internal Bindings bindings;
700 private Stack<CatchTag> catch_stack = new Stack<CatchTag> ();
701 private int catch_count = 0;
703 internal Domain (Symbol name) { this.name = name; }
705 public Domain (Symbol name, object context)
706 : this (name, basic, context) { }
708 public Domain (Symbol name, Domain parent, object context) : this (name)
710 termtypes = new Dictionary<Symbol, MethodInfo> (parent.termtypes);
711 functions = new Dictionary<Symbol, Function> (parent.functions);
712 variables = new Dictionary<Symbol, Variable> (parent.variables);
713 this.context = context;
716 internal void PushTerm (Term term)
718 call_stack.Push (term);
721 internal void PopTerm ()
726 internal void Bind (Variable vari, Term value)
728 bindings = Bindings.Bind (bindings, vari, value);
731 internal void UnboundTo (Bindings boundary)
733 if (bindings != null)
734 bindings = bindings.UnboundTo (boundary);
737 internal void Catch (CatchTag tag)
739 catch_stack.Push (tag);
743 internal void Uncatch ()
746 if (catch_count > catch_stack.Count)
750 public bool Thrown () { return catch_count < catch_stack.Count; }
752 public bool Thrown (out bool caught)
754 if (catch_count < catch_stack.Count)
756 caught = catch_count == catch_stack.Count - 1;
763 internal void ThrowReturn ()
765 foreach (CatchTag elt in catch_stack)
768 if (elt.Tag == CatchTag.Return.Tag)
773 internal bool ThrowBreak ()
775 if (catch_stack.Peek ().Tag != CatchTag.Break.Tag)
781 internal void ThrowSymbol (Term tag)
783 foreach (CatchTag elt in catch_stack)
786 if (elt.Tag.Matches (tag))
791 internal Term ThrowError (Term tag)
794 ErrorTerm e = tag.objval as ErrorTerm;
795 e.CallStack = call_stack.ToArray ();
797 foreach (CatchTag elt in catch_stack)
800 if (elt.Tag.Matches (tag))
806 public void DefType (Type type)
808 if (! type.IsSubclassOf (typeof (TermValue)))
809 throw new Exception ("Not a subclass of TermValue: " + type);
810 BindingFlags flags = BindingFlags.Static | BindingFlags.NonPublic;
811 FieldInfo finfo = type.GetField ("name", flags);
812 if (finfo == null || finfo.FieldType != typeof (Symbol))
813 throw new Exception ("No \"name\" field of string type: " + type);
814 Symbol name = (Symbol) finfo.GetValue (null);
815 if (termtypes.ContainsKey (name)
816 || functions.ContainsKey (name))
817 throw new Exception ("already defined: " + name);
818 Type[] types = new Type[] { typeof (Domain), typeof (XmlNode) };
819 MethodInfo minfo = type.GetMethod ("Parser", types);
820 if (minfo == null || minfo.ReturnType != typeof (TermValue))
821 throw new Exception ("No \"Parser\" method of correct type: " + type);
822 termtypes[name] = minfo;
825 public void DefSubr (Builtin builtin, string str, bool setvar,
826 int min_arg, int max_arg, params string[] aliases)
829 if (termtypes.ContainsKey (name))
830 throw new Exception ("already defined as termtype: " + name);
831 Function func = new Function.Subroutine (builtin, name, setvar,
833 functions[name] = func;
834 foreach (string a in aliases)
835 functions[(Symbol) a] = func;
838 public void DefSpecial (Builtin builtin, string str, bool setvar,
839 int min_arg, int max_arg,
840 params string[] aliases)
843 if (termtypes.ContainsKey (name))
844 throw new Exception ("already defined as termtype: " + name);
845 Function func = new Function.SpecialForm (builtin, name, setvar,
847 functions[name] = func;
848 foreach (string a in aliases)
849 functions[(Symbol) a] = func;
852 public void DefAlias (string alias, string str)
854 functions[(Symbol) alias] = functions[(Symbol) str];
857 public void Defun (Symbol name, Symbol[] args, Term[] body,
862 if (termtypes.ContainsKey (name))
863 throw new Exception ("already defined as termtype: " + name);
864 if (prototype || ! functions.TryGetValue (name, out func))
866 func = new Function.Lambda (this, name, args);
867 functions[name] = func;
870 ((Function.Lambda) func).SetBody (body);
873 public void Defun (XmlNode node, bool prototype)
875 Symbol name = node.Attributes[Qfname].Value;
876 if (termtypes.ContainsKey (name))
877 throw new Exception ("already defined as termtype: " + name);
880 if (prototype || ! functions.TryGetValue (name, out func))
882 func = new Function.Lambda (this, node);
883 functions[name] = func;
886 ((Function.Lambda) func).SetBody (this, node);
889 public void Defun (Function func)
891 functions[func.name] = func;
894 public void Defmacro (XmlNode node, bool prototype)
896 Symbol name = node.Attributes[Qfname].Value;
897 if (termtypes.ContainsKey (name))
898 throw new Exception ("already defined as termtype: " + name);
901 if (prototype || ! functions.TryGetValue (name, out func))
903 func = new Function.Macro (this, node);
904 functions[name] = func;
907 ((Function.Macro) func).SetBody (this, node);
910 public Variable Defvar (XmlNode node)
912 Symbol name = node.Attributes[0].Value;
916 node = node.FirstChild;
917 if (node != null && node.Name == Qdescription)
919 desc = node.InnerText;
920 node = node.NextSibling;
926 Symbol type = node.Name;
927 XmlNodeList range_list = null;
929 string val = node.InnerText;
931 node = node.NextSibling;
934 range_list = node.ChildNodes;
935 nranges = range_list.Count;
938 if (type == Qinteger)
940 int n = parse_integer (val);
942 if (range_list != null)
944 range = new int[nranges * 2];
945 for (int i = 0; i < nranges; i++)
947 XmlNode nd = range_list[i];
948 if (nd.Name == Qrange)
951 = parse_integer (nd.FirstChild.InnerText);
953 = parse_integer (nd.LastChild.InnerText);
959 = parse_integer (nd.FirstChild.InnerText);
963 vari = DefvarInt (name, n, desc, range);
965 else if (type == Qstring)
967 string[] range = null;
968 if (range_list != null)
970 range = new string[nranges];
971 for (int i = 0; i < nranges; i++)
972 range[i] = range_list[i].FirstChild.InnerText;
974 vari = DefvarStr (name, val, desc, range);
976 else if (type == Qsymbol)
978 Symbol[] range = null;
979 if (range_list != null)
981 range = new Symbol[nranges];
982 for (int i = 0; i < nranges; i++)
983 range[i] = range_list[i].FirstChild.InnerText;
985 vari = DefvarSym (name, (Symbol) val, desc, range);
988 throw new Exception ("Unknown type: " + type);
992 if (variables.TryGetValue (name, out vari))
993 vari = vari.Clone (this);
995 vari = new Variable (this, name, Zero);
996 variables[name] = vari;
1001 public Variable Defvar (Variable vari)
1003 vari = vari.Clone (this);
1004 variables[vari.name] = vari;
1008 internal Variable Defvar (Symbol name)
1010 Variable vari = new Variable (this, name, Zero);
1011 variables[name] = vari;
1015 public Variable DefvarInt (Symbol name, int n, string desc, int[] range)
1019 if (variables.TryGetValue (name, out vari))
1021 Variable.Int intvari = vari as Variable.Int;
1022 if (intvari == null)
1023 throw new Exception ("Variable type mismatch: " + name);
1026 if (! intvari.IsSubrange (range))
1027 throw new Exception ("Variable range mismatch: " + name);
1028 intvari.Range = range;;
1031 intvari.Description = desc;
1035 vari = new Variable.Int (this, name, n, desc, range);
1036 variables[name] = vari;
1041 public Variable DefvarStr (Symbol name, string str, string desc,
1046 if (variables.TryGetValue (name, out vari))
1048 Variable.Str strvari = vari as Variable.Str;
1049 if (strvari == null)
1050 throw new Exception ("Variable type mismatch: " + name);
1053 if (! strvari.IsSubrange (range))
1054 throw new Exception ("Variable range mismatch: " + name);
1055 strvari.Range = range;
1058 strvari.Description = desc;
1062 vari = new Variable.Str (this, name, str, desc, range);
1063 variables[name] = vari;
1068 public Variable DefvarSym (Symbol name, Symbol sym, string desc,
1073 if (variables.TryGetValue (name, out vari))
1075 Variable.Sym symvari = vari as Variable.Sym;
1076 if (symvari == null)
1077 throw new Exception ("Variable type mismatch: " + name);
1080 if (! symvari.IsSubrange (range))
1081 throw new Exception ("Variable range mismatch: " + name);
1082 symvari.Range = range;
1085 symvari.Description = desc;
1089 vari = new Variable.Sym (this, name, sym, desc, range);
1090 variables[name] = vari;
1095 internal Function GetFunc (Symbol name)
1099 if (! functions.TryGetValue (name, out func))
1100 throw new Exception ("Unknown function: " + name);
1104 public bool CopyFunc (Domain domain, Symbol name)
1106 Function func = GetFunc (name);
1108 domain.functions[name] = func;
1112 public void CopyFunc (Domain domain)
1114 foreach (KeyValuePair<Symbol, Function> kv in functions)
1115 domain.functions[kv.Key] = kv.Value;
1118 public Variable GetVar (Symbol name, bool create)
1122 if (! variables.TryGetValue (name, out vari))
1126 variables[name] = vari = new Variable (this, name, Zero);
1131 public override string ToString ()
1133 string str = "<(functions";
1134 foreach (KeyValuePair<Symbol, Function> kv in functions)
1135 str += " " + kv.Key;
1136 str += ") (variabls";
1137 foreach (KeyValuePair<Symbol, Variable> kv in variables)
1138 str += " " + kv.Value;
1140 if (bindings != null)
1141 str += " " + bindings;
1142 if (context != null)
1143 str += " (" + context + ")";
1148 internal void TraceWrite (string fmt, params string[] arg)
1150 if (trace_depth > depth)
1152 for (int i = 0; i < depth; i++)
1153 Console.Write (" ");
1154 Console.WriteLine (fmt, arg);
1158 public object SaveValues ()
1160 Dictionary<Variable,Term> values = new Dictionary<Variable,Term> ();
1162 foreach (KeyValuePair<Symbol,Variable> kv in variables)
1163 values[kv.Value] = kv.Value.Value.Clone ();
1167 public void RestoreValues (object values)
1169 foreach (KeyValuePair<Variable,Term> kv
1170 in (Dictionary<Variable,Term>) values)
1171 kv.Key.Value = kv.Value;
1175 public delegate Term Builtin (Domain domain, Variable vari, Term[] args);
1177 private static Domain basic = new Domain ("basic");
1179 static Xexpression ()
1181 basic.DefType (typeof (Varref));
1182 basic.DefType (typeof (Funcall));
1183 basic.DefType (typeof (ErrorTerm));
1185 basic.DefSubr (Fset, "set", true, 1, 1, "=");
1186 basic.DefSubr (Fnot, "not", false, 1, 1, "!");
1187 basic.DefSubr (Fadd, "add", true, 1, -1, "+");
1188 basic.DefSubr (Fmul, "mul", true, 1, -1, "*");
1189 basic.DefSubr (Fsub, "sub", true, 1, -1, "-");
1190 basic.DefSubr (Fdiv, "div", true, 1, -1, "/");
1191 basic.DefSubr (Fmod, "mod", true, 1, 2, "%");
1192 basic.DefSubr (Flogior, "logior", true, 1, -1, "|");
1193 basic.DefSubr (Flogand, "logand", true, 1, -1, "&");
1194 basic.DefSubr (Flsh, "lsh", true, 1, 2, "<<");
1195 basic.DefSubr (Frsh, "rsh", true, 1, 2, ">>");
1196 basic.DefSubr (Feq, "eq", false, 2, -1, "==");
1197 basic.DefSubr (Fnoteq, "noteq", false, 2, 2, "!=");
1198 basic.DefSubr (Flt, "lt", false, 2, -1, "<");
1199 basic.DefSubr (Fle, "le", false, 2, -1, "<=");
1200 basic.DefSubr (Fgt, "gt", false, 2, -1, ">");
1201 basic.DefSubr (Fge, "ge", false, 2, -1, ">=");
1202 basic.DefSubr (Fappend, "append", true, 0, -1);
1203 basic.DefSubr (Fconcat, "concat", true, 0, -1);
1204 basic.DefSubr (Fnth, "nth", false, 2, 2);
1205 basic.DefSubr (Fcopy, "copy", false, 1, 1);
1206 basic.DefSubr (Fins, "ins", true, 2, 2);
1207 basic.DefSubr (Fdel, "del", true, 2, 2);
1208 basic.DefSubr (Feval, "eval", false, 1, 1);
1209 basic.DefSubr (Fbreak, "break", false, 0, 1);
1210 basic.DefSubr (Freturn, "return", false, 0, 1);
1211 basic.DefSubr (Fthrow, "throw", false, 1, 2);
1213 basic.DefSpecial (Fand, "and", false, 1, -1, "&&");
1214 basic.DefSpecial (For, "or", false, 1, -1, "||");
1215 basic.DefSpecial (Fprogn, "progn", false, 0, -1, "expr");
1216 basic.DefSpecial (Fif, "if", false, 2, 3);
1217 basic.DefSpecial (Fwhen, "when", false, 1, -1);
1218 basic.DefSpecial (Floop, "loop", false, 1, -1);
1219 basic.DefSpecial (Fwhile, "while", false, 1, -1);
1220 basic.DefSpecial (Fcond, "cond", false, 1, -1);
1221 basic.DefSpecial (Fforeach, "foreach", true, 2, -1);
1222 basic.DefSpecial (Fquote, "quote", false, 1, 1);
1223 basic.DefSpecial (Ftype, "type", false, 1, 1);
1224 basic.DefSpecial (Fcatch, "catch", true, 2, -1);
1227 private static Term Fset (Domain domain, Variable vari, Term[] args)
1230 return new Term (new ErrorTerm (Error.NoVariable, ""));
1231 vari.Value = args[0];
1235 private static Term Fnot (Domain domain, Variable vari, Term[] args)
1237 return args[0].IsTrue ? Zero : One;
1240 private static Term Fadd (Domain domain, Variable vari, Term[] args)
1242 int n = vari == null ? 0 : vari.Value.Intval;
1244 foreach (Term arg in args)
1246 return (vari == null ? new Term (n) : vari.SetValue (n));
1249 private static Term Fmul (Domain domain, Variable vari, Term[] args)
1251 int n = vari == null ? 1 : vari.Value.Intval;
1252 foreach (Term arg in args)
1254 return (vari == null ? new Term (n) : vari.SetValue (n));
1257 private static Term Fsub (Domain domain, Variable vari, Term[] args)
1268 n = vari.Value.Intval;
1271 while (i < args.Length)
1272 n -= args[i++].Intval;
1273 return (vari == null ? new Term (n) : vari.SetValue (n));
1276 private static Term Fdiv (Domain domain, Variable vari, Term[] args)
1287 n = vari.Value.Intval;
1290 while (i < args.Length)
1291 n /= args[i++].Intval;
1292 return (vari == null ? new Term (n) : vari.SetValue (n));
1295 private static Term Fmod (Domain domain, Variable vari, Term[] args)
1297 int n = args[0].Intval % args[1].Intval;
1299 return (vari == null ? new Term (n) : vari.SetValue (n));
1302 private static Term Flogior (Domain domain, Variable vari, Term[] args)
1304 int n = vari == null ? 0 : vari.Value.Intval;
1305 foreach (Term arg in args)
1307 return (vari == null ? new Term (n) : vari.SetValue (n));
1310 private static Term Flogand (Domain domain, Variable vari, Term[] args)
1321 n = vari.Value.Intval;
1324 while (i < args.Length)
1325 n &= args[i++].Intval;
1326 return (vari == null ? new Term (n) : vari.SetValue (n));
1329 private static Term Flsh (Domain domain, Variable vari, Term[] args)
1331 int n = args[0].Intval << args[1].Intval;
1332 return (vari == null ? new Term (n) : vari.SetValue (n));
1335 private static Term Frsh (Domain domain, Variable vari, Term[] args)
1337 int n = args[0].Intval >> args[1].Intval;
1338 return (vari == null ? new Term (n) : vari.SetValue (n));
1341 private static Term Feq (Domain domain, Variable vari, Term[] args)
1345 if (o.objval == null)
1347 for (int i = 1; i < args.Length; i++)
1348 if (args[i].objval != null || args[i].intval != o.intval)
1353 for (int i = 1; i < args.Length; i++)
1354 if (o.objval.Equals (args[i].objval))
1360 private static Term Fnoteq (Domain domain, Variable vari, Term[] args)
1362 return Feq (domain, vari, args);
1365 private static Term Flt (Domain domain, Variable vari, Term[] args)
1367 int n = args[0].Intval;
1369 for (int i = 1; i < args.Length; i++)
1371 int n1 = args[i].Intval;
1379 private static Term Fle (Domain domain, Variable vari, Term[] args)
1381 int n = args[0].Intval;
1382 for (int i = 1; i < args.Length; i++)
1384 int n1 = args[i].Intval;
1392 private static Term Fgt (Domain domain, Variable vari, Term[] args)
1394 int n = args[0].Intval;
1395 for (int i = 1; i < args.Length; i++)
1397 int n1 = args[i].Intval;
1405 private static Term Fge (Domain domain, Variable vari, Term[] args)
1407 int n = args[0].Intval;
1408 for (int i = 1; i < args.Length; i++)
1410 int n1 = args[i].Intval;
1418 private static Term Fappend (Domain domain, Variable vari, Term[] args)
1423 list = new List<Term> ();
1425 list = vari.Value.Listval;
1427 foreach (Term arg in args)
1430 list.AddRange ((List<Term>) arg.objval);
1438 result.objval = list;
1444 private static Term Fconcat (Domain domain, Variable vari, Term[] args)
1451 str = vari.Value.Strval;
1453 foreach (Term arg in args)
1456 str += (string) arg.objval;
1457 else if (arg.IsList)
1458 foreach (Term term in (List<Term>) arg.objval)
1459 str += (char) term.Intval;
1461 str += (char) arg.Intval;
1471 return vari.SetValue (str);
1474 private static Term Fnth (Domain domain, Variable vari, Term[] args)
1480 result.intval = ((string) args[1].objval)[args[0].Intval];
1481 result.objval = null;
1483 else if (args[1].IsList)
1485 result = ((List<Term>) args[1].objval)[args[0].Intval];
1488 throw new Exception ("Term is not enumelable: " + args[1]);
1492 private static Term Fcopy (Domain domain, Variable vari, Term[] args)
1497 result.objval = new List<Term> (args[0].Listval);
1501 private static Term Fins (Domain domain, Variable vari, Term[] args)
1503 Term term = vari.Value;
1507 string str = term.Strval.Insert (args[0].Intval, args[1].Strval);
1508 vari.SetValue (str);
1510 else if (vari.Value.IsList)
1511 vari.Value.Listval.InsertRange (args[0].Intval, args[1].Listval);
1513 throw new Exception ("term is not collection: " + vari.Value);
1517 private static Term Fdel (Domain domain, Variable vari, Term[] args)
1519 if (vari.Value.IsStr)
1522 = vari.Value.Strval.Remove (args[0].Intval,
1523 args[1].Intval - args[0].Intval);
1524 vari.SetValue (str);
1526 else if (vari.Value.IsList)
1527 vari.Value.Listval.RemoveRange (args[0].Intval,
1528 args[1].Intval - args[0].Intval);
1530 throw new Exception ("term is not collection: " + vari.Value);
1534 private static Term Fand (Domain domain, Variable vari, Term[] args)
1536 foreach (Term arg in args)
1537 if (! arg.Eval (domain).IsTrue)
1542 private static Term For (Domain domain, Variable vari, Term[] args)
1544 foreach (Term arg in args)
1545 if (arg.Eval (domain).IsTrue)
1550 private static Term Feval (Domain domain, Variable vari, Term[] args)
1552 return (args[0].Eval (domain));
1555 private static Term Fprogn (Domain domain, Variable vari, Term[] args)
1559 foreach (Term arg in args)
1560 result = arg.Eval (domain);
1564 private static Term Fif (Domain domain, Variable vari, Term[] args)
1566 if (args[0].Eval (domain).IsTrue)
1567 return args[1].Eval (domain);
1568 if (args.Length == 2)
1570 return args[2].Eval (domain);
1573 private static Term Fwhen (Domain domain, Variable vari, Term[] args)
1575 if (! args[0].Eval (domain).IsTrue)
1578 for (int i = 1; i < args.Length; i++)
1579 result = args[i].Eval (domain);
1583 private static Term Freturn (Domain domain, Variable vari, Term[] args)
1585 domain.ThrowReturn ();
1586 return args.Length == 0 ? Zero : args[0];
1589 private static Term Fbreak (Domain domain, Variable vari, Term[] args)
1591 if (! domain.ThrowBreak ())
1592 return domain.ThrowError (new Term (Error.NoOuterLoop, null));
1593 return args.Length == 0 ? Zero : args[0];
1596 private static Term Floop (Domain domain, Variable vari, Term[] args)
1600 domain.Catch (CatchTag.Break);
1601 while (! domain.Thrown ())
1602 foreach (Term arg in args)
1604 result = arg.Eval (domain);
1605 if (domain.Thrown ())
1614 private static Term Fwhile (Domain domain, Variable vari, Term[] args)
1618 domain.Catch (CatchTag.Break);
1619 while (! domain.Thrown () && args[0].Eval (domain).IsTrue)
1620 for (int i = 1; i < args.Length; i++)
1622 result = args[i].Eval (domain);
1623 if (domain.Thrown ())
1632 private static Term Fcond (Domain domain, Variable vari, Term[] args)
1634 foreach (Term arg in args)
1636 List<Term> list = arg.Listval;
1637 Term result = list[0].Eval (domain);
1641 for (int i = 1; i < list.Count; i++)
1644 result = list[i].Eval (domain);
1646 if (domain.Thrown ())
1655 private static Term Fforeach (Domain domain, Variable vari, Term[] args)
1657 Term result = args[0].Eval (domain);
1658 if (domain.Thrown ())
1660 List<Term> list = result.Listval;
1661 Bindings current = domain.bindings;
1664 domain.Catch (CatchTag.Break);
1665 foreach (Term term in list)
1667 domain.Bind (vari, term);
1669 for (int i = 1; i < args.Length; i++)
1671 result = args[i].Eval (domain);
1672 if (domain.Thrown ())
1676 domain.UnboundTo (current);
1685 private static Term Fquote (Domain domain, Variable vari, Term[] args)
1690 private static Term Ftype (Domain domain, Variable vari, Term[] args)
1696 if (args[0].IsSymbol)
1703 public static Term Fcatch (Domain domain, Variable vari, Term[] args)
1708 domain.Catch (new CatchTag (args[0].Symval));
1709 for (int i = 1; i < args.Length; i++)
1711 result = args[i].Eval (domain);
1712 if (domain.Thrown (out caught))
1718 vari.Value = result;
1726 vari.Value = result;
1730 public static Term Fthrow (Domain domain, Variable vari, Term[] args)
1732 if (args[0].IsSymbol)
1734 domain.ThrowSymbol (args[0]);
1735 return (args[args.Length - 1]);
1737 if (args[0].IsError)
1738 return domain.ThrowError (args[0]);
1739 return domain.ThrowError (new Term (Error.InvalidArgumentType,
1740 args[0].ToString ()));
1743 public abstract class TermValue
1745 public virtual Term Eval (Domain domain) { return new Term (this); }
1746 public virtual TermValue Clone () { return this; }
1747 public virtual bool IsTrue { get { return true; } }
1748 public virtual bool Matches (TermValue other) { return Equals (other); }
1749 public override abstract bool Equals (object obj);
1750 public override abstract int GetHashCode ();
1751 public abstract string ToString (bool detail);
1754 private class Varref : TermValue
1756 private static Symbol name = "varref";
1757 public static Symbol Name { get { return name; } }
1759 private Symbol vname;
1760 private Variable vari;
1762 public Varref (Symbol vname) { this.vname = vname; }
1764 public override Term Eval (Domain domain)
1766 if (vari == null || vari.domain != domain)
1767 vari = domain.GetVar (vname, true);
1771 public static TermValue Parser (Domain domain, XmlNode node)
1773 return new Varref ((Symbol) node.Attributes[Qvname].Value);
1776 public override bool Equals (object obj)
1778 Varref varref = obj as Varref;
1779 return (varref != null && varref.vari.name == vari.name);
1782 public override int GetHashCode ()
1784 return vari.name.GetHashCode ();
1787 public override string ToString () { return ToString (true); }
1789 public override string ToString (bool detail)
1791 return "<varref vname=\"" + vname + "\"/>";
1795 private class Funcall : TermValue
1797 private static Symbol name = "funcall";
1798 public static Symbol Name { get { return name; } }
1800 internal Function func;
1801 internal Variable vari;
1802 internal Term[] args;
1804 public Funcall (Function func, Variable vari, Term[] args)
1806 int nargs = args.Length;
1808 if (nargs < func.min_arg
1809 || (func.max_arg >= 0 && nargs > func.max_arg))
1810 throw_exception ("Invalid number of arguments to {0}: ",
1812 if (! func.setvar && vari != null)
1813 throw_exception ("vname attribute not acceptable: ", func.name);
1819 public static TermValue Parser (Domain domain, XmlNode node)
1821 Symbol fname = node.Name;
1824 if (fname == Qfuncall)
1825 fname = node.Attributes[Qfname].Value;
1826 Function func = domain.GetFunc (fname);
1828 attr = node.Attributes[Qvname];
1829 vari = attr == null ? null : domain.GetVar (attr.Value, true);
1830 XmlNodeList nlist = node.ChildNodes;
1831 int nargs = nlist.Count;
1832 Term[] args = new Term[nargs];
1833 for (int i = 0; i < nargs; i++)
1834 args[i] = new Term (domain, nlist[i]);
1835 return new Funcall (func, vari, args);
1838 public override Term Eval (Domain domain)
1840 domain.TraceWrite (ToString ());
1842 Term result = func.Call (domain, vari, args);
1844 domain.TraceWrite ("=> {0}", result.ToString ());
1848 public override TermValue Clone ()
1850 return new Funcall (func, vari, args);
1853 public override bool Equals (object obj)
1855 Funcall funcall = obj as Funcall;
1857 && funcall.func == func
1858 && funcall.vari == vari
1859 && funcall.args.Length == args.Length);
1862 public override int GetHashCode ()
1864 return func.GetHashCode () ^ args.Length;
1867 public override string ToString () { return ToString (true); }
1869 public override string ToString (bool detail)
1871 string str = "<" + func.name;
1873 str += " vname=\"" + vari.name + "\"";
1874 if (args.Length == 0 || ! detail)
1877 if (func is Function.SpecialForm)
1879 for (int i = 0; i < args.Length; i++)
1883 foreach (Term e in args)
1885 return (str + "</" + func.name + ">");
1889 internal class ErrorTerm : TermValue
1891 private static Symbol name = "error";
1892 public static Symbol Name { get { return name; } }
1894 private readonly Symbol ename;
1895 private string message;
1896 private Term[] stack;
1898 public ErrorTerm (Symbol ename, string message)
1901 this.message = message;
1904 public static TermValue Parser (Domain domain, XmlNode node)
1906 XmlAttribute attr = node.Attributes[Qename];
1907 Symbol ename = attr == null ? Qnull : (Symbol) attr.Value;
1908 string message = node.InnerText;
1909 return new ErrorTerm (ename, message);
1912 public Term[] CallStack { get { return stack; } set { stack = value; } }
1914 public override TermValue Clone ()
1916 return new ErrorTerm (ename, message);
1919 public override bool Equals (object obj)
1921 ErrorTerm e = obj as ErrorTerm;
1922 if (e == null || e.ename != ename || e.message != message
1923 || (e.stack == null ? stack != null
1924 : (stack == null || e.stack.Length != stack.Length)))
1927 for (int i = 0; i < stack.Length; i++)
1928 if (! stack[i].Equals (e.stack[i]))
1933 public override int GetHashCode ()
1935 return ename.GetHashCode ();
1938 public override bool Matches (TermValue term)
1940 ErrorTerm e = term as ErrorTerm;
1941 return (e != null && (ename == Qnull || e.ename == ename));
1944 public override string ToString () { return ToString (true); }
1946 public override string ToString (bool detail)
1948 string str = "<error type=\"" + ename + "\">";
1949 if (message != null)
1952 for (int i = 0; i < stack.Length; i++)
1953 str += stack[i].ToString (false);
1954 return str + "</error>";
1961 public object objval;
1963 // <integer>...</integer>
1964 public Term (int i) { intval = i; objval = null; }
1965 // <symbol>...</symbol>
1966 public Term (Symbol name) { intval = 0; objval = name; }
1967 // <string>...</string>
1968 public Term (string str) { intval = 0; objval = str; }
1970 public Term (List<Term> list) { intval = 0; objval = list; }
1971 // <error ename="ERROR-NAME">ERROR-MESSASGE</error>
1972 public Term (Symbol name, string message)
1975 objval = new ErrorTerm (name, message);
1978 public Term (TermValue obj) { intval = 0; objval = obj; }
1980 public Term (Domain domain, XmlNode node)
1982 Symbol name = node.Name;
1984 if (name == Qinteger)
1986 intval = parse_integer (node.InnerText);
1992 if (name == Qsymbol)
1993 objval = (Symbol) node.InnerText;
1994 else if (name == Qstring)
1995 objval = node.InnerText.Clone ();
1996 else if (name == Qlist)
1998 List<Term> list = new List<Term> ();
1999 for (node = node.FirstChild; node != null;
2000 node = node.NextSibling)
2001 list.Add (new Term (domain, node));
2008 if (domain.termtypes.TryGetValue (name, out minfo))
2009 objval = (TermValue) minfo.Invoke (null, new Object[] { domain, node});
2012 Funcall funcall = (Funcall) Funcall.Parser (domain, node);
2013 if (funcall.func is Function.Macro)
2015 Term result = funcall.Eval (domain);
2016 intval = result.intval;
2017 objval = result.objval;
2026 // <varref vname="VNAME"/>
2027 public Term (Domain domain, Symbol vname)
2030 objval = new Varref (vname);
2033 // <funcall fname="FNAME">...</funcall>
2034 public Term (Domain domain, Symbol fname, Term[] args)
2035 : this (domain, fname, Qnull, args) { }
2037 // <funcall fname="FNAME" vname="VNAME">...</funcall>
2038 public Term (Domain domain, Symbol fname, Symbol vname, Term[] args)
2042 Function func = domain.GetFunc (fname);
2043 Variable vari = vname == Qnull ? null : domain.GetVar (vname, true);
2044 Funcall funcall = new Funcall (func, vari, args);
2045 if (func is Function.Macro)
2047 Term result = funcall.Eval (domain);
2048 intval = result.intval;
2049 objval = result.objval;
2055 public object Objval {
2058 throw new Exception ("term is an integer: " + this);
2066 throw new Exception ("term is not integer: " + this);
2071 public string Strval {
2074 throw new Exception ("term is not a string: " + this);
2075 return (string) objval;
2079 public string Symval {
2082 throw new Exception ("term is not a symbol: " + this);
2083 return (Symbol) objval;
2087 public List<Term> Listval {
2090 throw new Exception ("term is not a list: " + this);
2091 return (List<Term>) objval;
2095 public bool IsTrue {
2097 return (objval == null
2099 : objval is List<Term>
2100 ? (((List<Term>) objval).Count != 0)
2101 : objval is TermValue
2102 ? ((TermValue) objval).IsTrue
2107 public bool IsInt { get { return (objval == null); } }
2108 public bool IsStr { get { return (objval is string); } }
2109 public bool IsSymbol { get { return (objval is Symbol); } }
2110 public bool IsList { get { return (objval is List<Term>); } }
2111 public bool IsError { get { return (objval is ErrorTerm); } }
2113 public Term Eval (Domain domain)
2116 domain.PushTerm (this);
2117 if (objval == null || objval is Symbol || objval is string
2118 || objval is List<Term>)
2120 return ((TermValue) objval).Eval (domain);
2126 public Term Clone ()
2128 if (objval == null || objval is Symbol || objval is string)
2130 if (objval is List<Term>)
2132 List<Term> list = new List<Term> ();
2133 list.InsertRange (0, ((List<Term>) objval));
2134 return new Term (list);
2136 return new Term (((TermValue) objval).Clone ());
2139 public static bool operator== (Term t1, Term t2)
2141 return t1.Equals (t2);
2144 public static bool operator!= (Term t1, Term t2) { return ! (t1 == t2); }
2146 public override bool Equals (object obj)
2148 if (! (obj is Term))
2150 Term term = (Term) obj;
2152 return term.IsInt && term.Intval == Intval;
2154 return term.IsStr && term.Strval == Strval;
2156 return term.IsSymbol && term.Symval == Symval;
2161 List<Term> l1 = objval as List<Term>;
2162 List<Term> l2 = term.objval as List<Term>;
2164 if (l1.Count != l2.Count)
2166 for (int i = 0; i < l1.Count; i++)
2167 if (! l1[i].Equals (l2[i]))
2171 return ((TermValue) objval).Equals (obj);
2174 public override int GetHashCode () { return intval; }
2176 public bool Matches (Term term)
2179 return term.IsInt && term.Intval == Intval;
2181 return term.IsStr && term.Strval == Strval;
2183 return term.IsSymbol && term.Symval == Symval;
2185 return (((List<Term>) objval).Count > 0
2186 && ((List<Term>) objval)[0].Matches (term));
2187 return ((TermValue) objval).Matches ((TermValue) term.objval);
2190 public override string ToString () { return ToString (true); }
2192 public string ToString (bool detail)
2197 str = "<integer>" + intval + "</integer>";
2198 else if (objval is Symbol)
2199 str = "<symbol>" + objval + "</symbol>";
2200 else if (objval is string)
2201 str = "<string>" + objval + "</string>";
2202 else if (objval is List<Term>)
2207 foreach (Term e in (List<Term>) objval)
2214 else if (objval is Term)
2215 str = "<quote>" + objval + "</quote>";
2216 else if (objval is TermValue)
2217 str = ((TermValue) objval).ToString (detail);
2219 throw new Exception ("invalid Term object: " + objval);
2224 static private Term Zero = new Term (0);
2225 static private Term One = new Term (1);
2226 static private Term TermInt = new Term (Qinteger);
2227 static private Term TermStr = new Term (Qstring);
2228 static private Term TermSymbol = new Term (Qsymbol);
2229 static private Term TermList = new Term (Qlist);
2230 static private Term TermTerm = new Term ((Symbol) "term");
2232 internal static int parse_integer (string str)
2234 int len = str.Length;
2235 bool negative = false;
2238 return (len == 0 ? 0 : str[0] - '0');
2245 if ((c == '0' || c == '#') && str[1] == 'x')
2248 for (int idx = 2; idx < len; idx++)
2254 i = i * 16 + (c - '0');
2258 i = i * 16 + (c - 'A');
2262 i = i * 16 + (c - 'a');
2271 for (int idx = 1; idx < len; idx++)
2274 if (c < '0' || c > '9')
2276 i = i * 10 + (c - '0');
2278 return negative ? - i : i;
2281 private Term[] terms;
2283 public static Term[] ParseTerms (Domain domain, XmlNode node)
2286 for (XmlNode n = node; n != null; n = n.NextSibling)
2287 if (n.NodeType == XmlNodeType.Element)
2289 if (n.Name == Qdefun)
2290 domain.Defun (n, true);
2291 else if (n.Name == Qdefmacro)
2292 domain.Defmacro (n, true);
2293 else if (n.Name == Qdefvar)
2298 Term[] terms = new Term[nterms];
2300 for (XmlNode n = node; n != null; n = n.NextSibling)
2301 if (n.NodeType == XmlNodeType.Element)
2303 if (n.Name == Qdefun)
2304 domain.Defun (n, false);
2305 else if (n.Name == Qdefmacro)
2306 domain.Defmacro (n, false);
2307 else if (n.Name != Qdefvar)
2308 terms[i++]= new Term (domain, n);
2313 public static Term Eval (Domain domain, Term[] terms)
2315 Term result = new Term (0);
2316 foreach (Term term in terms)
2319 if (result.Objval is Funcall)
2320 while ((result = result.Eval (domain)).Objval is Funcall);
2326 public Xexpression (Domain domain, XmlNode node)
2328 terms = ParseTerms (domain, node);
2331 public Xexpression (Domain domain, string url)
2333 XmlDocument doc = new XmlDocument (Symbol.NameTable);
2336 using (XmlTextReader reader = new XmlTextReader (url, doc.NameTable))
2340 } while (reader.NodeType != XmlNodeType.None
2341 && (reader.NodeType != XmlNodeType.Element
2342 || reader.Name != Qexpr));
2343 if (reader.NodeType == XmlNodeType.None)
2344 throw new Exception ("Node <expr> not found");
2345 node = doc.ReadNode (reader);
2347 terms = ParseTerms (domain, node.FirstChild);
2350 public Term Eval (Domain domain)
2356 domain.Catch (CatchTag.Return);
2357 foreach (Term term in terms)
2359 result = term.Eval (domain);
2360 if (domain.Thrown ())
2369 public override string ToString ()
2372 for (int i = 0; i < terms.Length; i++)