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 Nvarref = "varref";
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 Nfixed = "fixed";
98 private static Name Noptional = "optional";
99 private static Name Nrest = "rest";
101 private static Name Ndefvar = "defvar";
102 private static Name Nvname = "vname";
103 private static Name Ndescription = "description";
104 private static Name Nrange = "range";
106 private static Name Nbreak = "break";
107 private static Name Nreturn = "return";
109 internal abstract class Function
112 public int min_arg, max_arg;
114 public Function () { }
116 public Function (Name name, int min_arg, int max_arg)
119 this.min_arg = min_arg;
120 this.max_arg = max_arg;
123 public abstract Term Call (Domain domain, Variable vari, Term[] args);
125 public override string ToString ()
130 internal class Subroutine : Function
132 public Builtin builtin;
135 public Subroutine (Builtin builtin, Name name, bool setvar,
136 int min_arg, int max_arg)
137 : base (name, min_arg, max_arg)
139 this.builtin = builtin;
142 public override Term Call (Domain domain, Variable vari, Term[] args)
144 Term[] newargs = new Term[args.Length];
146 for (int i = 0; i < args.Length; i++)
148 newargs[i] = args[i].Eval (domain);
152 return builtin (domain, vari, newargs);
156 internal class SpecialForm : Function
158 public Builtin builtin;
160 public SpecialForm (Builtin builtin, Name name,
161 int min_arg, int max_arg)
162 : base (name, min_arg, max_arg)
164 this.builtin = builtin;
167 public override Term Call (Domain domain, Variable vari, Term[] args)
169 return builtin (domain, vari, args);
173 internal class Lambda : Function
175 internal bool args_evalled;
176 internal Variable[] args;
177 internal Term[] body;
179 public Lambda (XmlNode node, Domain domain)
184 name = node.Attributes[Nfname].Value;
186 node = node.FirstChild;
188 && (node.Name == Nargs || node.Name == Nargs_unevalled))
191 args_evalled = node.Name == Nargs;
192 for (n = node.FirstChild; n != null; n = n.NextSibling)
194 if (n.Name == Nfixed)
196 else if (n.Name == Noptional)
198 else if (n.Name == Nrest)
201 throw new Exception ("Invalid argument type: " + n);
204 max_arg = nfixed + noptional + nrest;
205 args = new Variable[max_arg];
207 for (int i = 0; i < max_arg; n = n.NextSibling)
208 args[i++] = domain.Defvar ((Name) n.Attributes[0].Value);
214 min_arg = max_arg = 0;
218 public void SetBody (XmlNode node, Domain domain)
220 for (node = node.FirstChild; node != null; node = node.NextSibling)
221 if (node.Name != Ndescription
222 && node.Name != Nargs
223 && node.Name != Nargs_unevalled)
226 for (XmlNode n = node; n != null; n = n.NextSibling)
230 body = new Term[nterms];
231 for (nterms = 0; node != null; node = node.NextSibling, nterms++)
232 body[nterms] = new Term (node, domain);
236 public override Term Call (Domain domain, Variable vari, Term[] args)
238 Bindings current = domain.bindings;
245 Term[] newargs = new Term[args.Length];
246 for (i = 0; i < min_arg; i++)
247 newargs[i] = args[i].Eval (domain);
250 for (i = 0; i < min_arg; i++)
251 domain.Bind (this.args[i], args[i]);
256 domain.Catch (Nreturn);
257 foreach (Term term in body)
259 result = term.Eval (domain);
269 domain.UnboundTo (current);
276 public class Variable : Object
278 public readonly Name name;
281 public Variable (Name name, Term term)
287 public virtual Term Value
292 if (! ValueP (value))
293 throw new Exception ("Invalid value of " + name + ": " + value);
298 public override Term Eval (Domain domain) { return val; }
300 public virtual bool ValueP (Term term) { return true; }
302 public override string ToString () { return name + "(" + val + ")"; }
304 internal class Int : Variable
311 public Range[] ranges;
313 public Int (Name name, int i) : base (name, new Term (i)) { }
315 public override bool ValueP (Term term)
319 if (term.objval != null)
324 foreach (Range r in ranges)
325 if (i >= r.from && i <= r.to)
331 internal class Str : Variable
333 public string[] ranges;
335 public Str (Name name, string str) : base (name, new Term (str)) { }
337 public override bool ValueP (Term term)
339 if (! (term.objval is string))
343 string str = (string) term.objval;
344 foreach (string s in ranges)
352 internal class Bindings
354 private Variable vari;
355 private Term old_value;
356 private Bindings next;
358 private Bindings (Variable vari)
361 old_value = vari.val;
364 public static Bindings Bind (Bindings bindings, Variable vari, Term val)
366 Bindings b = new Bindings (vari);
373 internal Bindings UnboundTo (Bindings boundary)
375 for (Bindings b = this; b != boundary; b = b.next)
376 b.vari.val = b.old_value;
380 public override string ToString ()
382 string str = "(bindings";
383 for (Bindings b = this; b != null; b = b.next)
384 str += " " + vari.name + "=" + b.old_value;
390 internal class ThrowException : Exception
395 public ThrowException (Name tag, object value) : base ()
405 public object context;
406 public int depth = 0;
408 internal Dictionary<Name, Function> functions;
409 internal Dictionary<Name, Variable> variables;
410 internal Bindings bindings;
411 private Stack<Name> catch_stack = new Stack<Name> ();
412 private int catch_count = 0;
416 functions = new Dictionary<Name, Function> ();
417 variables = new Dictionary<Name, Variable> ();
420 public Domain (object context) : this (basic, context)
424 public Domain (Domain parent, object context)
426 functions = new Dictionary<Name, Function> (parent.functions);
427 variables = new Dictionary<Name, Variable> (parent.variables);
428 this.context = context;
431 internal void Bind (Variable vari, Term value)
433 bindings = Bindings.Bind (bindings, vari, value);
436 internal void UnboundTo (Bindings boundary)
438 if (bindings != null)
439 bindings = bindings.UnboundTo (boundary);
442 internal void Catch (Name name)
444 catch_stack.Push (name);
448 internal void Uncatch ()
451 if (catch_count > catch_stack.Count)
455 internal bool Thrown {
456 get { return catch_count < catch_stack.Count; }
459 internal void ThrowReturn ()
461 foreach (Name tag in catch_stack)
469 internal void ThrowBreak ()
471 if (catch_stack.Peek () != Nbreak)
472 throw new Exception ("No outer loop to break");
476 public void DefSubr (Builtin builtin, string str, bool setvar,
477 int min_arg, int max_arg, params string[] aliases)
480 Function func = new Function.Subroutine (builtin, name, setvar,
482 functions[name] = func;
483 foreach (string a in aliases)
484 functions[(Name) a] = func;
487 public void DefSpecial (Builtin builtin, string str,
488 int min_arg, int max_arg,
489 params string[] aliases)
492 Function func = new Function.SpecialForm (builtin, name,
494 functions[name] = func;
495 foreach (string a in aliases)
496 functions[(Name) a] = func;
499 public void DefAlias (string alias, string str)
501 functions[(Name) alias] = functions[(Name) str];
504 internal Function.Lambda RegisterFunction (XmlNode node)
506 Function.Lambda lambda = new Function.Lambda (node, this);
508 functions[lambda.name] = lambda;
512 internal Function Defun (XmlNode node)
514 Name name = node.Attributes[Nfname].Value;
517 if (! functions.TryGetValue (name, out func))
518 func = RegisterFunction (node);
519 ((Function.Lambda) func).SetBody (node, this);
523 public void Defvar (XmlNode node)
525 Name name = node.Attributes[0].Value;
528 node = node.FirstChild;
529 if (node.Name == Ndescription)
530 node = node.NextSibling;
533 Name type = node.Name;
534 XmlNodeList range_list = null;
536 string val = node.InnerText;
538 node = node.NextSibling;
541 range_list = node.ChildNodes;
542 nranges = range_list.Count;
545 if (type == Ninteger)
547 Variable.Int vi = new Variable.Int (name, parse_integer (val));
548 if (range_list != null)
550 vi.ranges = new Variable.Int.Range[nranges];
552 for (int i = 0; i < nranges; i++)
554 XmlNode n = range_list[i];
556 if (n.Name == Nrange)
559 parse_integer (n.FirstChild.InnerText);
561 parse_integer (n.LastChild.InnerText);
565 int num = parse_integer (n.InnerText);
566 vi.ranges[i].from = vi.ranges[i].to = num;
572 else if (type == Nstring)
574 Variable.Str vs = new Variable.Str (name, val);
575 if (range_list != null)
576 vs.ranges = new string[nranges];
577 for (int i = 0; i < nranges; i++)
578 vs.ranges[i] = range_list[i].Value;
582 throw new Exception ("Unknown type: " + type);
585 vari = new Variable (name, Zero);
586 variables[name] = vari;
589 internal Variable Defvar (Name name)
591 Variable vari = new Variable (name, Zero);
592 variables[name] = vari;
596 internal Function GetFunc (Name name)
600 if (! functions.TryGetValue (name, out func))
601 throw new Exception ("Unknown function: " + name);
605 public bool CopyFunc (Domain domain, Name name)
607 Function func = GetFunc (name);
609 domain.functions[name] = func;
613 public void CopyFunc (Domain domain)
615 foreach (KeyValuePair<Name, Function> kv in functions)
616 domain.functions[kv.Key] = kv.Value;
619 internal Variable GetVar (Name name)
623 if (! variables.TryGetValue (name, out vari))
624 variables[name] = vari = new Variable (name, Zero);
628 public override string ToString ()
630 string str = "<(functions";
631 foreach (KeyValuePair<Name, Function> kv in functions)
633 str += ") (variabls";
634 foreach (KeyValuePair<Name, Variable> kv in variables)
637 if (bindings != null)
638 str += " " + bindings;
640 str += " (" + context + ")";
645 internal void DebugWrite (bool head, string fmt, params string[] arg)
647 if (debug_level > depth)
651 Console.WriteLine ();
652 for (int i = 0; i < depth; i++)
655 Console.Write (fmt, arg);
660 public delegate Term Builtin (Domain domain, Variable vari, Term[] args);
662 private static Domain basic = new Domain ();
664 static Xexpression ()
666 basic.DefSubr (Fset, "set", true, 1, 1, "=");
667 basic.DefSubr (Fnot, "not", false, 1, 1, "!");
668 basic.DefSubr (Fadd, "add", true, 1, -1, "+");
669 basic.DefSubr (Fmul, "mul", true, 1, -1, "*");
670 basic.DefSubr (Fsub, "sub", true, 1, -1, "-");
671 basic.DefSubr (Fdiv, "div", true, 1, -1, "/");
672 basic.DefSubr (Fmod, "mod", true, 1, 2, "%");
673 basic.DefSubr (Flogior, "logior", true, 1, -1, "|");
674 basic.DefSubr (Flogand, "logand", true, 1, -1, "&");
675 basic.DefSubr (Flsh, "lsh", true, 1, 2, "<<");
676 basic.DefSubr (Frsh, "rsh", true, 1, 2, ">>");
677 basic.DefSubr (Feq, "eq", false, 2, -1, "==");
678 basic.DefSubr (Fnoteq, "noteq", false, 2, 2, "!=");
679 basic.DefSubr (Flt, "lt", false, 2, -1, "<");
680 basic.DefSubr (Fle, "le", false, 2, -1, "<=");
681 basic.DefSubr (Fgt, "gt", false, 2, -1, ">");
682 basic.DefSubr (Fge, "ge", false, 2, -1, ">=");
683 basic.DefSubr (Fappend, "append", true, 0, -1);
684 basic.DefSubr (Fconcat, "concat", true, 0, -1);
685 basic.DefSubr (Fnth, "nth", false, 2, 2);
686 basic.DefSubr (Fcopy, "copy", false, 1, 1);
687 basic.DefSubr (Fins, "ins", true, 2, 2);
688 basic.DefSubr (Fdel, "del", true, 2, 2);
689 basic.DefSubr (Feval, "eval", false, 1, 1);
690 basic.DefSubr (Fbreak, "break", false, 0, 1);
691 basic.DefSubr (Freturn, "return", false, 0, 1);
692 basic.DefSpecial (Fand, "and", 1, -1, "&&");
693 basic.DefSpecial (For, "or", 1, -1, "||");
694 basic.DefSpecial (Fprogn, "progn", 0, -1, "expr");
695 basic.DefSpecial (Fif, "if", 2, 3);
696 basic.DefSpecial (Fwhen, "when", 1, -1);
697 basic.DefSpecial (Floop, "loop", 1, -1);
698 basic.DefSpecial (Fwhile, "while", 1, -1);
699 basic.DefSpecial (Fcond, "cond", 1, -1);
700 basic.DefSpecial (Fforeach, "foreach", 2, -1);
701 basic.DefSpecial (Fquote, "quote", 1, 1);
702 basic.DefSpecial (Ftype, "type", 1, 1);
705 private static Term Fset (Domain domain, Variable vari, Term[] args)
707 vari.Value = args[0];
711 private static Term Fnot (Domain domain, Variable vari, Term[] args)
713 return args[0].IsTrue ? Zero : One;
716 private static Term Fadd (Domain domain, Variable vari, Term[] args)
718 int n = vari == null ? 0 : vari.val.Intval;
720 foreach (Term arg in args)
728 private static Term Fmul (Domain domain, Variable vari, Term[] args)
730 int n = vari == null ? 1 : vari.val.Intval;
731 foreach (Term arg in args)
739 private static Term Fsub (Domain domain, Variable vari, Term[] args)
753 while (i < args.Length)
754 n -= (int) args[i++];
761 private static Term Fdiv (Domain domain, Variable vari, Term[] args)
775 while (i < args.Length)
776 n /= args[i++].Intval;
783 private static Term Fmod (Domain domain, Variable vari, Term[] args)
786 return (args[0].Intval % args[1].Intval);
787 vari.val.intval = vari.val.Intval % args[0].Intval;
791 private static Term Flogior (Domain domain, Variable vari, Term[] args)
793 int n = vari == null ? 0 : vari.val.Intval;
794 foreach (Term arg in args)
802 private static Term Flogand (Domain domain, Variable vari, Term[] args)
816 while (i < args.Length)
817 n &= (int) args[i++];
824 private static Term Flsh (Domain domain, Variable vari, Term[] args)
827 return args[0].Intval << args[1].Intval;
828 vari.val.intval = vari.val.Intval << args[0].Intval;
832 private static Term Frsh (Domain domain, Variable vari, Term[] args)
835 return args[0].Intval >> args[1].Intval;
836 vari.val.intval = vari.val.Intval >> args[0].Intval;
840 private static Term Feq (Domain domain, Variable vari, Term[] args)
844 if (o.objval == null)
846 for (int i = 1; i < args.Length; i++)
847 if (args[i].objval != null || args[i].intval != o.intval)
852 for (int i = 1; i < args.Length; i++)
853 if (o.objval.Equals (args[i].objval))
859 private static Term Fnoteq (Domain domain, Variable vari, Term[] args)
861 return Feq (domain, vari, args);
864 private static Term Flt (Domain domain, Variable vari, Term[] args)
866 int n = (int) args[0];
868 for (int i = 1; i < args.Length; i++)
870 int n1 = (int) args[i];
878 private static Term Fle (Domain domain, Variable vari, Term[] args)
880 int n = (int) args[0];
881 for (int i = 1; i < args.Length; i++)
883 int n1 = (int) args[i];
891 private static Term Fgt (Domain domain, Variable vari, Term[] args)
893 int n = (int) args[0];
894 for (int i = 1; i < args.Length; i++)
896 int n1 = (int) args[i];
904 private static Term Fge (Domain domain, Variable vari, Term[] args)
906 int n = (int) args[0];
907 for (int i = 1; i < args.Length; i++)
909 int n1 = (int) args[i];
917 private static Term Fappend (Domain domain, Variable vari, Term[] args)
922 list = new List<Term> ();
924 list = vari.val.Listval;
926 foreach (Term arg in args)
929 list.AddRange ((List<Term>) arg.objval);
937 result.objval = list;
940 vari.val.objval = list;
944 private static Term Fconcat (Domain domain, Variable vari, Term[] args)
951 str = vari.val.Strval;
953 foreach (Term arg in args)
956 str += (string) arg.objval;
958 foreach (Term term in (List<Term>) arg.objval)
959 str += (char) term.Intval;
961 str += (char) arg.Intval;
970 vari.val.objval = str;
974 private static Term Fnth (Domain domain, Variable vari, Term[] args)
980 result.intval = ((string) args[1].objval)[args[0].Intval];
981 result.objval = null;
983 else if (args[1].IsList)
985 result = ((List<Term>) args[1].objval)[args[0].Intval];
988 throw new Exception ("Term is not enumelable: " + args[1]);
992 private static Term Fcopy (Domain domain, Variable vari, Term[] args)
997 result.objval = new List<Term> (args[0].Listval);
1001 private static Term Fins (Domain domain, Variable vari, Term[] args)
1005 = vari.val.Strval.Insert (args[0].Intval, args[1].Strval);
1006 else if (vari.val.IsList)
1007 vari.val.Listval.InsertRange (args[0].Intval, args[1].Listval);
1009 throw new Exception ("term is not collection: " + vari.val);
1013 private static Term Fdel (Domain domain, Variable vari, Term[] args)
1017 = vari.val.Strval.Remove (args[0].Intval,
1018 args[1].Intval - args[0].Intval);
1020 else if (vari.val.IsList)
1021 vari.val.Listval.RemoveRange (args[0].Intval,
1022 args[1].Intval - args[0].Intval);
1024 throw new Exception ("term is not collection: " + vari.val);
1028 private static Term Fand (Domain domain, Variable vari, Term[] args)
1030 foreach (Term arg in args)
1031 if (! arg.Eval (domain).IsTrue)
1036 private static Term For (Domain domain, Variable vari, Term[] args)
1038 foreach (Term arg in args)
1039 if (arg.Eval (domain).IsTrue)
1044 private static Term Feval (Domain domain, Variable vari, Term[] args)
1046 return (args[0].Eval (domain));
1049 private static Term Fprogn (Domain domain, Variable vari, Term[] args)
1053 foreach (Term arg in args)
1054 result = arg.Eval (domain);
1058 private static Term Fif (Domain domain, Variable vari, Term[] args)
1060 if (args[0].Eval (domain).IsTrue)
1061 return args[1].Eval (domain);
1062 if (args.Length == 2)
1064 return args[2].Eval (domain);
1067 private static Term Fwhen (Domain domain, Variable vari, Term[] args)
1069 if (! args[0].Eval (domain).IsTrue)
1072 for (int i = 1; i < args.Length; i++)
1073 result = args[i].Eval (domain);
1077 private static Term Freturn (Domain domain, Variable vari, Term[] args)
1079 domain.ThrowReturn ();
1080 return args.Length == 0 ? Zero : args[0];
1083 private static Term Fbreak (Domain domain, Variable vari, Term[] args)
1085 domain.ThrowBreak ();
1086 return args.Length == 0 ? Zero : args[0];
1089 private static Term Floop (Domain domain, Variable vari, Term[] args)
1093 domain.Catch (Nbreak);
1094 while (! domain.Thrown)
1095 foreach (Term arg in args)
1097 result = arg.Eval (domain);
1107 private static Term Fwhile (Domain domain, Variable vari, Term[] args)
1111 domain.Catch (Nbreak);
1112 while (! domain.Thrown && args[0].Eval (domain).IsTrue)
1113 for (int i = 1; i < args.Length; i++)
1115 result = args[i].Eval (domain);
1125 private static Term Fcond (Domain domain, Variable vari, Term[] args)
1127 foreach (Term arg in args)
1129 List<Term> list = arg.Listval;
1130 Term result = list[0].Eval (domain);
1134 for (int i = 1; i < list.Count; i++)
1135 result = list[i].Eval (domain);
1142 private static Term Fforeach (Domain domain, Variable vari,
1145 Term result = args[0].Eval (domain);
1148 List<Term> list = result.Listval;
1149 Bindings current = domain.bindings;
1152 domain.Catch (Nbreak);
1153 foreach (Term term in list)
1155 domain.Bind (vari, term);
1157 for (int i = 1; i < args.Length; i++)
1159 result = args[i].Eval (domain);
1164 domain.UnboundTo (current);
1173 private static Term Fquote (Domain domain, Variable vari, Term[] args)
1175 return new Term (args[0]);
1178 private static Term Ftype (Domain domain, Variable vari, Term[] args)
1191 public abstract class Object
1193 public abstract Term Eval (Domain domain);
1196 private class Funcall : Object
1198 internal Function func;
1199 internal Variable vari;
1200 internal Term[] args;
1202 public Funcall (Function func, Variable vari, Term[] args)
1209 public override Term Eval (Domain domain)
1211 domain.DebugWrite (true, "(({0}", func.name);
1212 for (int i = 0; i < args.Length; i++)
1213 domain.DebugWrite (false, " {0}", args[i].ToString ());
1214 domain.DebugWrite (false, ")");
1216 Term result = func.Call (domain, vari, args);
1218 domain.DebugWrite (true, " ==> {0})", result.ToString ());
1222 public override string ToString ()
1224 string str = "<funcall fname=\"" + func.name;
1226 return str + "\"/>";
1228 foreach (Term e in args)
1230 return (str + "</funcall>");
1237 public object objval;
1239 public Term (int i) { intval = i; objval = null; }
1240 public Term (Name name) { intval = 0; objval = name; }
1241 public Term (string str) { intval = 0; objval = str; }
1242 public Term (List<Term> list) { intval = 0; objval = list; }
1243 public Term (Term term) { intval = 0; objval = term; }
1244 public Term (Object obj) { intval = 0; objval = obj; }
1246 public Term (XmlNode node, Domain domain)
1248 Name name = node.Name;
1250 if (name == Ninteger)
1252 intval = parse_integer (node.InnerText);
1258 if (name == Nsymbol)
1259 objval = (Name) node.InnerText;
1260 else if (name == Nstring)
1261 objval = node.InnerText.Clone ();
1262 else if (name == Nvarref)
1263 objval = domain.GetVar ((Name) node.Attributes[0].Value);
1264 else if (name == Nlist)
1266 List<Term> list = new List<Term> ();
1267 for (node = node.FirstChild; node != null;
1268 node = node.NextSibling)
1269 list.Add (new Term (node, domain));
1275 Variable vari = null;
1278 if (name == Nfuncall)
1279 name = node.Attributes[0].Value;
1280 else if (node.Attributes[Nvname] != null)
1281 vari = domain.GetVar (node.Attributes[Nvname].Value);
1282 func = domain.GetFunc (name);
1283 XmlNodeList nlist = node.ChildNodes;
1284 int nargs = nlist.Count;
1286 if (nargs < func.min_arg
1287 || (func.max_arg >= 0 && nargs > func.max_arg))
1288 throw new Exception ("Invalid number of arguments to: "
1289 + name + " " + nargs);
1290 args = new Term[nargs];
1291 for (int i = 0; i < nlist.Count; i++)
1292 args[i] = new Term (nlist[i], domain);
1293 objval = new Funcall (func, vari, args);
1301 throw new Exception ("term is not integer: " + this);
1306 public string Strval {
1309 throw new Exception ("term is not string: " + this);
1310 return (string) objval;
1314 public List<Term> Listval {
1317 throw new Exception ("term is not list: " + this);
1318 return (List<Term>) objval;
1322 public bool IsTrue {
1324 return (objval == null
1326 : objval is List<Term>
1327 ? (((List<Term>) objval).Count != 0)
1331 public bool IsInt { get { return (objval == null); } }
1332 public bool IsStr { get { return (objval is string); } }
1333 public bool IsName { get { return (objval is Name); } }
1334 public bool IsList { get { return (objval is List<Term>); } }
1336 public Term Eval (Domain domain)
1338 if (objval == null || objval is Name || objval is string)
1340 if (objval is List<Term>)
1341 return new Term ((List<Term>) objval);
1342 if (objval is Object)
1343 return ((Object) objval).Eval (domain);
1344 if (objval is Variable)
1345 return ((Variable) objval).val;
1347 return (Term) objval;
1348 throw new Exception ("invalid Term object: " + objval);
1351 public static explicit operator int (Term term)
1353 if (term.objval != null)
1354 throw new Exception ("Not an integer term: " + term);
1358 public static explicit operator Name (Term term)
1360 return (Name) term.objval;
1363 public static implicit operator Term (int i)
1365 return new Term (i);
1368 public override string ToString ()
1373 str = "<integer>" + intval + "</integer>";
1374 else if (objval is Name)
1375 str = "<symbol>" + objval + "</symbol>";
1376 else if (objval is string)
1377 str = "<string>" + objval + "</string>";
1378 else if (objval is List<Term>)
1381 foreach (Term e in (List<Term>) objval)
1385 else if (objval is Funcall)
1386 str = "<funcall fname=\"" + ((Funcall) objval).func.name + "\"/>";
1387 else if (objval is Variable)
1388 str = "<variable vname=\"" + ((Variable) objval).name + "\"/>";
1389 else if (objval is Term)
1390 str = "<quote>" + objval + "</quote>";
1392 throw new Exception ("invalid Term object: " + objval);
1397 static Term Zero = new Term (0);
1398 static Term One = new Term (1);
1399 static Term TermInt = new Term (Ninteger);
1400 static Term TermStr = new Term (Nstring);
1401 static Term TermName = new Term (Nsymbol);
1402 static Term TermList = new Term (Nlist);
1403 static Term TermTerm = new Term ((Name) "term");
1405 internal static int parse_integer (string str)
1407 int len = str.Length;
1408 bool negative = false;
1411 return (len == 0 ? 0 : str[0] - '0');
1418 if (c == '0' && str[1] == 'x')
1421 for (int idx = 2; idx < len; idx++)
1427 i = i * 16 + (c - '0');
1431 i = i * 16 + (c - 'A');
1435 i = i * 16 + (c - 'a');
1444 for (int idx = 1; idx < len; idx++)
1447 if (c < '0' || c > '9')
1449 i = i * 10 + (c - '0');
1451 return negative ? - i : i;
1454 private Term[] terms;
1456 public Xexpression (string url, Domain domain)
1458 XmlDocument doc = new XmlDocument (Name.Table);
1461 using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
1465 } while (reader.NodeType != XmlNodeType.None
1466 && (reader.NodeType != XmlNodeType.Element
1467 || reader.Name != Nexpr));
1468 if (reader.NodeType == XmlNodeType.None)
1469 throw new Exception ("Node <expr> not found");
1470 node = doc.ReadNode (reader);
1474 for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
1475 if (n.NodeType == XmlNodeType.Element)
1477 if (n.Name == Ndefun)
1478 domain.RegisterFunction (n);
1479 else if (n.Name == Ndefvar)
1485 terms = new Term[nterms];
1487 for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
1488 if (n.NodeType == XmlNodeType.Element)
1490 if (n.Name == Ndefun)
1492 else if (n.Name != Ndefvar)
1493 terms[i++]= new Term (n, domain);
1497 public Term Eval (Domain domain)
1503 domain.Catch (Nreturn);
1504 foreach (Term term in terms)
1506 result = term.Eval (domain);
1516 public override string ToString ()
1519 for (int i = 0; i < terms.Length; i++)