2 using System.Collections;
3 using System.Collections.Generic;
7 namespace System.Xml.Expression
9 public class Xexpression
11 public static int debug_level = 0;
13 public struct Name : IEquatable<Name>
15 private static NameTable nt = new NameTable ();
19 public Name (string str)
24 public static implicit operator Name (string str)
26 return new Name (str);
29 public static implicit operator string (Name name)
34 public static bool operator== (Name n1, Name n2)
36 return (object) n1.name == (object) n2.name;
39 public static bool operator!= (Name n1, Name n2)
41 return (object) n1.name != (object) n2.name;
44 public static bool operator== (Name n1, string n2)
46 return (object) n1.name == (object) n2;
49 public static bool operator!= (Name n1, string n2)
51 return (object) n1.name != (object) n2;
54 public static bool operator== (string n1, Name n2)
56 return (object) n1 == (object) n2.name;
59 public static bool operator!= (string n1, Name n2)
61 return (object) n1 != (object) n2.name;
64 public bool Equals (Name name)
66 return Object.ReferenceEquals (this.name, name.name);
69 public override bool Equals (object obj)
71 return Object.ReferenceEquals (this.name, obj);
74 public override int GetHashCode ()
76 return name.GetHashCode ();
79 public static NameTable Table { get { return nt; } }
81 public override string ToString () { return name; }
84 private static Name Nexpr = "expr";
86 private static Name Nfuncall = "funcall";
87 private static Name Nvariable = "variable";
88 private static Name Ninteger = "integer";
89 private static Name Nstring = "string";
90 private static Name Nsymbol = "symbol";
91 private static Name Nlist = "list";
93 private static Name Ndefun = "defun";
94 private static Name Nfname = "fname";
95 private static Name Nargs = "args";
96 private static Name Nargs_unevalled = "args-unevalled";
97 private static Name Noptional = "optional";
98 private static Name Nrest = "rest";
99 private static Name Nbody = "body";
101 private static Name Ndefvar = "defvar";
102 private static Name Ndescription = "description";
103 private static Name Nrange = "range";
105 private static Name Nprogn = "progn";
107 internal abstract class Function
110 public int min_arg, max_arg;
112 public Function () { }
114 public Function (Name name, int min_arg, int max_arg)
117 this.min_arg = min_arg;
118 this.max_arg = max_arg;
121 public abstract Term Call (Domain domain, Term[] args);
123 public override string ToString ()
128 internal class Subroutine : Function
130 public Builtin builtin;
132 public Subroutine (Builtin builtin, Name name,
133 int min_arg, int max_arg)
134 : base (name, min_arg, max_arg)
136 this.builtin = builtin;
139 public override Term Call (Domain domain, Term[] args)
141 Term[] newargs = new Term[args.Length];
143 for (int i = 0; i < args.Length; i++)
144 newargs[i] = args[i].Eval (domain);
145 return builtin (domain, newargs);
149 internal class SpecialForm : Function
151 public Builtin builtin;
153 public SpecialForm (Builtin builtin, Name name,
154 int min_arg, int max_arg)
155 : base (name, min_arg, max_arg)
157 this.builtin = builtin;
160 public override Term Call (Domain domain, Term[] args)
162 return builtin (domain, args);
166 internal class Lambda : Function
168 internal bool args_evalled;
169 internal Term[] args;
170 internal Term[] body;
172 public Lambda (XmlNode node)
174 int nargs = 0, noptions = 0, nrest = 0;
175 name = node.Attributes[Nfname].Value;
177 node = node.FirstChild;
179 && (node.Name == Nargs || node.Name == Nargs_unevalled))
182 args_evalled = node.Name == Nargs;
183 for (n = node.FirstChild; n != null; n = n.NextSibling)
185 if (n.Name != Nsymbol)
189 if (n != null && n.Name == Noptional)
190 for (n = n.NextSibling; n != null; n = n.NextSibling)
199 max_arg = nargs + noptions + nrest;
200 args = new Term[max_arg];
202 for (int i = 0; i < max_arg; n = n.NextSibling)
203 if (n.Name == Nsymbol)
204 args[i++] = new Term (n, null);
210 min_arg = max_arg = 0;
214 public void SetBody (XmlNode node, Domain domain)
217 for (node = node.FirstChild; node != null && node.Name != Nbody;
218 node = node.NextSibling);
221 XmlNodeList nlist = node.ChildNodes;
223 body = new Term[nlist.Count];
224 for (int i = 0; i < nlist.Count; i++)
225 body[i] = new Term (nlist[i], domain);
229 public override Term Call (Domain domain, Term[] args)
231 Bindings current = domain.bindings;
238 Term[] newargs = new Term[args.Length];
239 for (i = 0; i < min_arg; i++)
240 newargs[i] = args[i].Eval (domain);
243 for (i = 0; i < min_arg; i++)
245 Variable vari = domain.GetVar ((Name) this.args[i]);
246 domain.Bind (vari, args[i]);
249 foreach (Term term in body)
250 result = term.Eval (domain);
252 domain.UnboundTo (current);
259 internal abstract class Variable
261 public readonly Name name;
264 public Variable (Name name, Term term)
275 if (! ValueP (value))
276 throw new Exception ("Invalid value of " + name + ": " + value);
281 public abstract bool ValueP (Term term);
283 public override string ToString () { return name + "(" + val + ")"; }
285 internal class Int : Variable
292 public Range[] ranges;
294 public Int (Name name, int i) : base (name, new Term (i)) { }
296 public override bool ValueP (Term term)
300 if (term.objval != null)
305 foreach (Range r in ranges)
306 if (i >= r.from && i <= r.to)
312 internal class Str : Variable
314 public string[] ranges;
316 public Str (Name name, string str) : base (name, new Term (str)) { }
318 public override bool ValueP (Term term)
320 if (! (term.objval is string))
324 string str = (string) term.objval;
325 foreach (string s in ranges)
332 internal class Misc : Variable
334 public Misc (Name name, Term term) : base (name, term) { }
336 public override bool ValueP (Term term) { return true; }
340 internal class Bindings
342 private Variable vari;
343 private Term old_value;
344 private Bindings next;
346 private Bindings (Variable vari)
349 old_value = vari.val;
352 public static Bindings Bind (Bindings bindings, Variable vari, Term val)
354 Bindings b = new Bindings (vari);
361 internal Bindings UnboundTo (Bindings boundary)
363 for (Bindings b = this; b != boundary; b = b.next)
364 b.vari.val = b.old_value;
368 public override string ToString ()
370 string str = "(bindings";
371 for (Bindings b = this; b != null; b = b.next)
372 str += " " + vari.name + "=" + b.old_value;
378 internal class ThrowException : Exception
383 public ThrowException (Name tag, object value) : base ()
393 public object context;
394 public int depth = 0;
396 internal Dictionary<Name, Function> functions;
397 internal Dictionary<Name, Variable> variables;
398 internal Bindings bindings;
402 functions = new Dictionary<Name, Function> ();
403 variables = new Dictionary<Name, Variable> ();
406 public Domain (object context) : this (basic, context)
410 public Domain (Domain parent, object context)
412 functions = new Dictionary<Name, Function> (parent.functions);
413 variables = new Dictionary<Name, Variable> (parent.variables);
414 this.context = context;
417 internal void Bind (Variable vari, Term value)
419 bindings = Bindings.Bind (bindings, vari, value);
422 internal void UnboundTo (Bindings boundary)
424 if (bindings != null)
425 bindings = bindings.UnboundTo (boundary);
428 public void DefSubr (Builtin builtin, string str,
429 int min_arg, int max_arg, params string[] aliases)
432 Function func = new Function.Subroutine (builtin, name,
434 functions[name] = func;
435 foreach (string a in aliases)
436 functions[(Name) a] = func;
439 public void DefSpecial (Builtin builtin, string str,
440 int min_arg, int max_arg,
441 params string[] aliases)
444 Function func = new Function.SpecialForm (builtin, name,
446 functions[name] = func;
447 foreach (string a in aliases)
448 functions[(Name) a] = func;
451 public void DefAlias (string alias, string str)
453 functions[(Name) alias] = functions[(Name) str];
456 internal Function.Lambda RegisterFunction (XmlNode node)
458 Function.Lambda lambda = new Function.Lambda (node);
460 functions[lambda.name] = lambda;
464 internal Function Defun (XmlNode node)
466 Name name = node.Attributes[Nfname].Value;
469 if (! functions.TryGetValue (name, out func))
470 func = RegisterFunction (node);
471 ((Function.Lambda) func).SetBody (node, this);
475 public void Defvar (XmlNode node)
477 Name name = node.Attributes[0].Value;
480 node = node.FirstChild;
481 if (node.Name == Ndescription)
482 node = node.NextSibling;
485 Name type = node.Name;
486 XmlNodeList range_list = null;
488 string val = node.InnerText;
490 node = node.NextSibling;
493 range_list = node.ChildNodes;
494 nranges = range_list.Count;
497 if (type == Ninteger)
499 Variable.Int vi = new Variable.Int (name, parse_integer (val));
500 if (range_list != null)
502 vi.ranges = new Variable.Int.Range[nranges];
504 for (int i = 0; i < nranges; i++)
506 XmlNode n = range_list[i];
508 if (n.Name == Nrange)
511 parse_integer (n.FirstChild.InnerText);
513 parse_integer (n.LastChild.InnerText);
517 int num = parse_integer (n.InnerText);
518 vi.ranges[i].from = vi.ranges[i].to = num;
524 else if (type == Nstring)
526 Variable.Str vs = new Variable.Str (name, val);
527 if (range_list != null)
528 vs.ranges = new string[nranges];
529 for (int i = 0; i < nranges; i++)
530 vs.ranges[i] = range_list[i].Value;
534 throw new Exception ("Unknown type: " + type);
537 vari = new Variable.Misc (name, Zero);
538 variables[name] = vari;
541 internal Function GetFunc (Name name)
545 if (! functions.TryGetValue (name, out func))
546 throw new Exception ("Unknown function: " + name);
550 public bool CopyFunc (Domain domain, Name name)
552 Function func = GetFunc (name);
554 domain.functions[name] = func;
558 public void CopyFunc (Domain domain)
560 foreach (KeyValuePair<Name, Function> kv in functions)
561 domain.functions[kv.Key] = kv.Value;
564 internal Variable GetVar (Name name)
568 if (! variables.TryGetValue (name, out vari))
569 variables[name] = vari = new Variable.Misc (name, Zero);
573 public override string ToString ()
575 string str = "<(functions";
576 foreach (KeyValuePair<Name, Function> kv in functions)
578 str += ") (variabls";
579 foreach (KeyValuePair<Name, Variable> kv in variables)
582 if (bindings != null)
583 str += " " + bindings;
585 str += " (" + context + ")";
590 internal void DebugWrite (bool head, string fmt, params string[] arg)
592 if (debug_level > depth)
596 Console.WriteLine ();
597 for (int i = 0; i < depth; i++)
600 Console.Write (fmt, arg);
605 public delegate Term Builtin (Domain domain, Term[] args);
607 private static Domain basic = new Domain ();
609 internal static Function Fprogn;
611 static Xexpression ()
613 basic.DefSubr (set_value, "set", 2, 2, "=");
614 basic.DefSpecial (and, "and", 1, -1, "&&");
615 basic.DefSpecial (or, "or", 1, -1, "||");
616 basic.DefSubr (not, "not", 1, 1, "!");
617 basic.DefSubr (add, "add", 2, -1, "+");
618 basic.DefSubr (mul, "mul", 2, -1, "*");
619 basic.DefSubr (sub, "sub", 1, -1, "-");
620 basic.DefSubr (div, "div", 2, -1, "/");
621 basic.DefSubr (mod, "mod", 2, 2, "%");
622 basic.DefSubr (logior, "logior", 2, -1, "|");
623 basic.DefSubr (logand, "logand", 2, -1, "&");
624 basic.DefSubr (add_set, "add-set", 2, -1, "+=");
625 basic.DefSubr (mul_set, "mul-set", 2, -1, "*=");
626 basic.DefSubr (sub_set, "sub-set", 2, -1, "-=");
627 basic.DefSubr (div_set, "div-set", 2, -1, "/=");
628 basic.DefSubr (mod_set, "mod-set", 2, 2, "%=");
629 basic.DefSubr (logior_set, "logior-set", 2, -1, "|=");
630 basic.DefSubr (logand_set, "logand-set", 2, -1, "&=");
631 basic.DefSubr (lsh, "lsh", 2, 2, "<<");
632 basic.DefSubr (rsh, "rsh", 2, 2, ">>");
633 basic.DefSubr (lsh_set, "lsh-set", 2, 2, "<<=");
634 basic.DefSubr (rsh_set, "rsh-set", 2, 2, ">>=");
635 basic.DefSubr (eq, "eq", 2, -1, "==");
636 basic.DefSubr (noteq, "noteq", 2, 2, "!=");
637 basic.DefSubr (less_than, "lt", 2, -1, "<");
638 basic.DefSubr (less_eq, "le", 2, -1, "<=");
639 basic.DefSubr (greater_than, "gt", 2, -1, ">");
640 basic.DefSubr (greater_eq, "ge", 2, -1, ">=");
641 basic.DefSubr (append, "append", 0, -1);
642 basic.DefSubr (concat, "concat", 0, -1);
643 basic.DefSubr (nth, "nth", 2, 2);
644 basic.DefSubr (copy, "copy", 1, 1);
645 basic.DefSubr (ins, "ins", 3, 3);
646 basic.DefSubr (del, "del", 3, 3);
647 basic.DefSubr (eval_clause, "eval", 1, 1);
648 basic.DefSpecial (quote_clause, "quote", 1, 1);
649 basic.DefSpecial (progn_clause, "progn", 0, -1, "expr");
650 basic.DefSpecial (if_clause, "if", 2, 3);
651 basic.DefSpecial (when_clause, "when", 1, -1);
652 basic.DefSpecial (while_clause, "while", 1, -1);
653 basic.DefSpecial (cond_clause, "cond", 1, -1);
654 basic.DefSpecial (foreach_clause, "foreach", 3, -1);
656 Fprogn = basic.GetFunc (Nprogn);
659 private static Term set_value (Domain domain, Term[] args)
661 Variable vari = domain.GetVar ((Name) args[0]);
663 vari.Value = args[1];
667 private static Term and (Domain domain, Term[] args)
669 foreach (Term arg in args)
670 if (! arg.Eval (domain).IsTrue)
675 private static Term or (Domain domain, Term[] args)
677 foreach (Term arg in args)
678 if (arg.Eval (domain).IsTrue)
683 private static Term not (Domain domain, Term[] args)
685 return args[0].IsTrue ? Zero : One;
688 private static Term add (Domain domain, Term[] args)
691 foreach (Term arg in args)
696 private static Term mul (Domain domain, Term[] args)
699 foreach (Term arg in args)
704 private static Term sub (Domain domain, Term[] args)
706 int n = (int) args[0];
707 if (args.Length == 1)
709 for (int i = 1; i < args.Length; i++)
714 private static Term div (Domain domain, Term[] args)
716 int n = (int) args[0];
717 for (int i = 1; i < args.Length; i++)
722 private static Term mod (Domain domain, Term[] args)
724 return ((int) args[0] % (int) args[1]);
727 private static Term logior (Domain domain, Term[] args)
730 foreach (Term arg in args)
735 private static Term logand (Domain domain, Term[] args)
737 int n = (int) args[0];
738 for (int i = 1; i < args.Length; i++)
743 private static Term add_set (Domain domain, Term[] args)
745 Variable vari = domain.GetVar ((Name) args[0]);
746 int n = (int) vari.val;
748 for (int i = 1; i < args.Length; i++)
754 private static Term mul_set (Domain domain, Term[] args)
756 Variable vari = domain.GetVar ((Name) args[0]);
757 int n = (int) vari.val;
759 for (int i = 1; i < args.Length; i++)
765 private static Term sub_set (Domain domain, Term[] args)
767 Variable vari = domain.GetVar ((Name) args[0]);
768 int n = (int) vari.val;
770 for (int i = 1; i < args.Length; i++)
776 private static Term div_set (Domain domain, Term[] args)
778 Variable vari = domain.GetVar ((Name) args[0]);
779 int n = (int) vari.val;
781 for (int i = 1; i < args.Length; i++)
787 private static Term mod_set (Domain domain, Term[] args)
789 Variable vari = domain.GetVar ((Name) args[0]);
790 int n = (int) vari.val;
792 for (int i = 1; i < args.Length; i++)
798 private static Term logior_set (Domain domain, Term[] args)
800 Variable vari = domain.GetVar ((Name) args[0]);
801 int n = (int) vari.val;
803 for (int i = 1; i < args.Length; i++)
809 private static Term logand_set (Domain domain, Term[] args)
811 Variable vari = domain.GetVar ((Name) args[0]);
812 int n = (int) vari.val;
814 for (int i = 1; i < args.Length; i++)
820 private static Term lsh (Domain domain, Term[] args)
822 return (int) args[0] << (int) args[1];
825 private static Term lsh_set (Domain domain, Term[] args)
827 Variable vari = domain.GetVar ((Name) args[0]);
828 int n = (int) vari.val;
835 private static Term rsh (Domain domain, Term[] args)
837 return (int) args[0] >> (int) args[1];
840 private static Term rsh_set (Domain domain, Term[] args)
842 Variable vari = domain.GetVar ((Name) args[0]);
843 int n = (int) vari.val;
850 private static Term eq (Domain domain, Term[] args)
854 if (o.objval == null)
856 for (int i = 1; i < args.Length; i++)
857 if (args[i].objval != null || args[i].intval != o.intval)
862 for (int i = 1; i < args.Length; i++)
863 if (o.objval.Equals (args[i].objval))
869 private static Term noteq (Domain domain, Term[] args)
871 return eq (domain, args);
874 private static Term less_than (Domain domain, Term[] args)
876 int n = (int) args[0];
878 for (int i = 1; i < args.Length; i++)
880 int n1 = (int) args[i];
888 private static Term less_eq (Domain domain, Term[] args)
890 int n = (int) args[0];
891 for (int i = 1; i < args.Length; i++)
893 int n1 = (int) args[i];
901 private static Term greater_than (Domain domain, Term[] args)
903 int n = (int) args[0];
904 for (int i = 1; i < args.Length; i++)
906 int n1 = (int) args[i];
914 private static Term greater_eq (Domain domain, Term[] args)
916 int n = (int) args[0];
917 for (int i = 1; i < args.Length; i++)
919 int n1 = (int) args[i];
927 private static Term append (Domain domain, Term[] args)
929 List<Term> list = new List<Term> ();
932 foreach (Term arg in args)
935 list.AddRange ((List<Term>) arg.objval);
940 result.objval = list;
944 private static Term concat (Domain domain, Term[] args)
949 foreach (Term arg in args)
952 str += (string) arg.objval;
954 foreach (Term term in (List<Term>) arg.objval)
955 str += (char) term.Intval;
957 str += (char) arg.Intval;
964 private static Term nth (Domain domain, Term[] args)
970 result.intval = ((string) args[1].objval)[args[0].Intval];
971 result.objval = null;
973 else if (args[1].IsList)
975 result = ((List<Term>) args[1].objval)[args[0].Intval];
978 throw new Exception ("Term is not enumelable: " + args[1]);
982 private static Term copy (Domain domain, Term[] args)
987 result.objval = new List<Term> (args[0].Listval);
991 private static Term ins (Domain domain, Term[] args)
995 string str = args[0].Strval.Insert (args[1].Intval, args[2].Strval);
996 args[0].objval = str;
998 else if (args[0].IsList)
1000 args[0].Listval.InsertRange (args[1].Intval, args[2].Listval);
1003 throw new Exception ("term is not collection: " + args[0]);
1008 private static Term del (Domain domain, Term[] args)
1012 string str = args[0].Strval.Remove (args[1].Intval,
1013 args[2].Intval - args[1].Intval);
1014 args[0].objval = str;
1016 else if (args[0].IsList)
1018 args[0].Listval.RemoveRange (args[1].Intval,
1019 args[2].Intval - args[1].Intval);
1022 throw new Exception ("term is not collection: " + args[0]);
1026 private static Term quote_clause (Domain domain, Term[] args)
1028 return new Term (args[0]);
1031 private static Term eval_clause (Domain domain, Term[] args)
1033 return (args[0].Eval (domain));
1036 private static Term progn_clause (Domain domain, Term[] args)
1040 foreach (Term arg in args)
1041 result = arg.Eval (domain);
1045 private static Term if_clause (Domain domain, Term[] args)
1047 if (args[0].Eval (domain).IsTrue)
1048 return args[1].Eval (domain);
1049 if (args.Length == 2)
1051 return args[2].Eval (domain);
1054 private static Term when_clause (Domain domain, Term[] args)
1056 if (! args[0].Eval (domain).IsTrue)
1059 for (int i = 1; i < args.Length; i++)
1060 result = args[i].Eval (domain);
1064 private static Term while_clause (Domain domain, Term[] args)
1066 while (args[0].Eval (domain).IsTrue)
1067 for (int i = 1; i < args.Length; i++)
1068 args[i].Eval (domain);
1072 private static Term cond_clause (Domain domain, Term[] args)
1074 foreach (Term arg in args)
1076 List<Term> list = arg.Listval;
1077 Term result = list[0].Eval (domain);
1081 for (int i = 1; i < list.Count; i++)
1082 result = list[i].Eval (domain);
1089 private static Term foreach_clause (Domain domain, Term[] args)
1091 Variable vari = domain.GetVar ((Name) args[0]);
1092 List<Term> list = args[1].Listval;
1093 Bindings current = domain.bindings;
1095 foreach (Term term in list)
1097 domain.Bind (vari, term);
1099 for (int i = 2; i < args.Length; i++)
1100 args[i].Eval (domain);
1102 domain.UnboundTo (current);
1112 public object objval;
1114 public Term (int i) { intval = i; objval = null; }
1115 public Term (Name name) { intval = 0; objval = name; }
1116 public Term (string str) { intval = 0; objval = str; }
1117 public Term (List<Term> list) { intval = 0; objval = list; }
1118 public Term (Term term) { intval = 0; objval = term; }
1120 public Term (XmlNode node, Domain domain)
1122 Name name = node.Name;
1124 if (name == Ninteger)
1126 intval = parse_integer (node.InnerText);
1132 if (name == Nsymbol)
1133 objval = (Name) node.InnerText;
1134 else if (name == Nstring)
1135 objval = node.InnerText.Clone ();
1136 else if (name == Nvariable)
1137 objval = domain.GetVar ((Name) node.Attributes[0].Value);
1138 else if (name == Nlist)
1140 List<Term> list = new List<Term> ();
1141 for (node = node.FirstChild; node != null;
1142 node = node.NextSibling)
1143 list.Add (new Term (node, domain));
1148 if (name == Nfuncall)
1149 name = node.Attributes[0].Value;
1151 Function func = domain.GetFunc (name);
1152 XmlNodeList nlist = node.ChildNodes;
1153 int nargs = nlist.Count;
1155 if (nargs < func.min_arg
1156 || (func.max_arg >= 0 && nargs > func.max_arg))
1157 throw new Exception ("Invalid number of arguments to: "
1158 + name + " " + nargs);
1159 Term[] args = new Term[nargs];
1160 for (int i = 0; i < nlist.Count; i++)
1161 args[i] = new Term (nlist[i], domain);
1162 objval = new Funcall (func, args);
1167 private class Funcall
1169 internal Function func;
1170 internal Term[] args;
1172 public Funcall (Function func, Term[] args)
1178 public Term Eval (Domain domain)
1180 domain.DebugWrite (true, "(({0}", func.name);
1181 for (int i = 0; i < args.Length; i++)
1182 domain.DebugWrite (false, " {0}", args[i].ToString ());
1183 domain.DebugWrite (false, ")");
1185 Term result = func.Call (domain, args);
1187 domain.DebugWrite (true, " ==> {0})", result.ToString ());
1191 public override string ToString ()
1193 string str = "<funcall fname=\"" + func.name;
1195 return str + "\"/>";
1197 foreach (Term e in args)
1199 return (str + "</funcall>");
1206 throw new Exception ("term is not integer: " + this);
1211 public string Strval {
1214 throw new Exception ("term is not string: " + this);
1215 return (string) objval;
1219 public List<Term> Listval {
1222 throw new Exception ("term is not list: " + this);
1223 return (List<Term>) objval;
1227 public bool IsTrue {
1229 return (objval == null
1231 : objval is List<Term>
1232 ? (((List<Term>) objval).Count != 0)
1236 public bool IsInt { get { return (objval == null); } }
1237 public bool IsStr { get { return (objval is string); } }
1238 public bool IsList { get { return (objval is List<Term>); } }
1240 public Term Eval (Domain domain)
1242 if (objval == null || objval is Name || objval is string)
1244 if (objval is List<Term>)
1245 return new Term ((List<Term>) objval);
1246 if (objval is Funcall)
1247 return ((Funcall) objval).Eval (domain);
1248 if (objval is Variable)
1249 return ((Variable) objval).val;
1251 return (Term) objval;
1252 throw new Exception ("invalid Term object: " + objval);
1255 public static explicit operator int (Term term)
1257 if (term.objval != null)
1258 throw new Exception ("Not an integer term: " + term);
1262 public static explicit operator Name (Term term)
1264 return (Name) term.objval;
1267 public static implicit operator Term (int i)
1269 return new Term (i);
1272 public override string ToString ()
1277 str = "<integer>" + intval + "</integer>";
1278 else if (objval is Name)
1279 str = "<symbol>" + objval + "</symbol>";
1280 else if (objval is string)
1281 str = "<string>" + objval + "</string>";
1282 else if (objval is List<Term>)
1285 foreach (Term e in (List<Term>) objval)
1289 else if (objval is Funcall)
1290 str = "<funcall fname=\"" + ((Funcall) objval).func.name + "\"/>";
1291 else if (objval is Variable)
1292 str = "<variable vname=\"" + ((Variable) objval).name + "\"/>";
1293 else if (objval is Term)
1294 str = "<quote>" + objval + "</quote>";
1296 throw new Exception ("invalid Term object: " + objval);
1301 static Term Zero = new Term (0);
1302 static Term One = new Term (1);
1304 internal static int parse_integer (string str)
1306 int len = str.Length;
1307 bool negative = false;
1310 return (len == 0 ? 0 : str[0] - '0');
1315 if (c == '0' && str[1] == 'x')
1318 for (int idx = 2; idx < len; idx++)
1324 i = i * 16 + (c - '0');
1328 i = i * 16 + (c - 'A');
1332 i = i * 16 + (c - 'a');
1341 for (int idx = 1; idx < len; idx++)
1344 if (c < '0' || c > '9')
1346 i = i * 10 + (c - '0');
1348 return negative ? - i : i;
1351 private Term[] terms;
1353 public Xexpression (string url, Domain domain)
1355 XmlDocument doc = new XmlDocument (Name.Table);
1358 using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
1362 } while (reader.NodeType != XmlNodeType.None
1363 && (reader.NodeType != XmlNodeType.Element
1364 || reader.Name != Nexpr));
1365 if (reader.NodeType == XmlNodeType.None)
1366 throw new Exception ("Node <expr> not found");
1367 node = doc.ReadNode (reader);
1371 for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
1372 if (n.NodeType == XmlNodeType.Element)
1374 if (n.Name == Ndefun)
1375 domain.RegisterFunction (n);
1376 else if (n.Name == Ndefvar)
1382 terms = new Term[nterms];
1384 for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
1385 if (n.NodeType == XmlNodeType.Element)
1387 if (n.Name == Ndefun)
1389 else if (n.Name != Ndefvar)
1390 terms[i++]= new Term (n, domain);
1394 public Term Eval (Domain domain)
1399 foreach (Term term in terms)
1400 result = term.Eval (domain);
1404 public override string ToString ()
1407 for (int i = 0; i < terms.Length; i++)