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 Nprogn = "progn";
107 private static Name Nbreak = "break";
108 private static Name Nreturn = "return";
110 internal abstract class Function
113 public int min_arg, max_arg;
115 public Function () { }
117 public Function (Name name, int min_arg, int max_arg)
120 this.min_arg = min_arg;
121 this.max_arg = max_arg;
124 public abstract Term Call (Domain domain, Variable vari, Term[] args);
126 public override string ToString ()
131 internal class Subroutine : Function
133 public Builtin builtin;
136 public Subroutine (Builtin builtin, Name name, bool setvar,
137 int min_arg, int max_arg)
138 : base (name, min_arg, max_arg)
140 this.builtin = builtin;
143 public override Term Call (Domain domain, Variable vari, Term[] args)
145 Term[] newargs = new Term[args.Length];
147 for (int i = 0; i < args.Length; i++)
149 newargs[i] = args[i].Eval (domain);
153 return builtin (domain, vari, newargs);
157 internal class SpecialForm : Function
159 public Builtin builtin;
161 public SpecialForm (Builtin builtin, Name name,
162 int min_arg, int max_arg)
163 : base (name, min_arg, max_arg)
165 this.builtin = builtin;
168 public override Term Call (Domain domain, Variable vari, Term[] args)
170 return builtin (domain, vari, args);
174 internal class Lambda : Function
176 internal bool args_evalled;
177 internal Variable[] args;
178 internal Term[] body;
180 public Lambda (XmlNode node, Domain domain)
185 name = node.Attributes[Nfname].Value;
187 node = node.FirstChild;
189 && (node.Name == Nargs || node.Name == Nargs_unevalled))
192 args_evalled = node.Name == Nargs;
193 for (n = node.FirstChild; n != null; n = n.NextSibling)
195 if (n.Name == Nfixed)
197 else if (n.Name == Noptional)
199 else if (n.Name == Nrest)
202 throw new Exception ("Invalid argument type: " + n);
205 max_arg = nfixed + noptional + nrest;
206 args = new Variable[max_arg];
208 for (int i = 0; i < max_arg; n = n.NextSibling)
209 args[i++] = domain.Defvar ((Name) n.Attributes[0].Value);
215 min_arg = max_arg = 0;
219 public void SetBody (XmlNode node, Domain domain)
221 for (node = node.FirstChild; node != null; node = node.NextSibling)
222 if (node.Name != Ndescription
223 && node.Name != Nargs
224 && node.Name != Nargs_unevalled)
227 for (XmlNode n = node; n != null; n = n.NextSibling)
231 body = new Term[nterms];
232 for (nterms = 0; node != null; node = node.NextSibling, nterms++)
233 body[nterms] = new Term (node, domain);
237 public override Term Call (Domain domain, Variable vari, Term[] args)
239 Bindings current = domain.bindings;
246 Term[] newargs = new Term[args.Length];
247 for (i = 0; i < min_arg; i++)
248 newargs[i] = args[i].Eval (domain);
251 for (i = 0; i < min_arg; i++)
252 domain.Bind (this.args[i], args[i]);
256 domain.Catch (Nreturn);
257 foreach (Term term in body)
259 result = term.Eval (domain);
268 domain.UnboundTo (current);
275 public abstract class Variable
277 public readonly Name name;
280 public Variable (Name name, Term term)
291 if (! ValueP (value))
292 throw new Exception ("Invalid value of " + name + ": " + value);
297 public abstract bool ValueP (Term term);
299 public override string ToString () { return name + "(" + val + ")"; }
301 internal class Int : Variable
308 public Range[] ranges;
310 public Int (Name name, int i) : base (name, new Term (i)) { }
312 public override bool ValueP (Term term)
316 if (term.objval != null)
321 foreach (Range r in ranges)
322 if (i >= r.from && i <= r.to)
328 internal class Str : Variable
330 public string[] ranges;
332 public Str (Name name, string str) : base (name, new Term (str)) { }
334 public override bool ValueP (Term term)
336 if (! (term.objval is string))
340 string str = (string) term.objval;
341 foreach (string s in ranges)
348 internal class Misc : Variable
350 public Misc (Name name, Term term) : base (name, term) { }
352 public override bool ValueP (Term term) { return true; }
356 internal class Bindings
358 private Variable vari;
359 private Term old_value;
360 private Bindings next;
362 private Bindings (Variable vari)
365 old_value = vari.val;
368 public static Bindings Bind (Bindings bindings, Variable vari, Term val)
370 Bindings b = new Bindings (vari);
377 internal Bindings UnboundTo (Bindings boundary)
379 for (Bindings b = this; b != boundary; b = b.next)
380 b.vari.val = b.old_value;
384 public override string ToString ()
386 string str = "(bindings";
387 for (Bindings b = this; b != null; b = b.next)
388 str += " " + vari.name + "=" + b.old_value;
394 internal class ThrowException : Exception
399 public ThrowException (Name tag, object value) : base ()
409 public object context;
410 public int depth = 0;
412 internal Dictionary<Name, Function> functions;
413 internal Dictionary<Name, Variable> variables;
414 internal Bindings bindings;
415 private Stack<Name> catch_stack = new Stack<Name> ();
416 private int catch_count = -1;
420 functions = new Dictionary<Name, Function> ();
421 variables = new Dictionary<Name, Variable> ();
424 public Domain (object context) : this (basic, context)
428 public Domain (Domain parent, object context)
430 functions = new Dictionary<Name, Function> (parent.functions);
431 variables = new Dictionary<Name, Variable> (parent.variables);
432 this.context = context;
435 internal void Bind (Variable vari, Term value)
437 bindings = Bindings.Bind (bindings, vari, value);
440 internal void UnboundTo (Bindings boundary)
442 if (bindings != null)
443 bindings = bindings.UnboundTo (boundary);
446 internal void Catch (Name name)
448 catch_stack.Push (name);
450 Console.WriteLine ("catch {0}", catch_count);
453 internal bool Catched {
455 Console.WriteLine ("catched {0} {1}",
458 return catch_stack.Count == catch_count; }
461 internal void ThrowReturn ()
463 Name tag = catch_stack.Peek ();
464 while (tag != Nreturn)
467 tag = catch_stack.Peek ();
469 catch_count = catch_stack.Count - 1;
472 internal void ThrowBreak ()
474 Name tag = catch_stack.Peek ();
476 throw new Exception ("No outer loop to break");
477 catch_count = catch_stack.Count - 1;
480 internal void Uncatch ()
483 catch_count = catch_stack.Count;
484 Console.WriteLine ("uncatch {0}", catch_count);
487 public void DefSubr (Builtin builtin, string str, bool setvar,
488 int min_arg, int max_arg, params string[] aliases)
491 Function func = new Function.Subroutine (builtin, name, setvar,
493 functions[name] = func;
494 foreach (string a in aliases)
495 functions[(Name) a] = func;
498 public void DefSpecial (Builtin builtin, string str,
499 int min_arg, int max_arg,
500 params string[] aliases)
503 Function func = new Function.SpecialForm (builtin, name,
505 functions[name] = func;
506 foreach (string a in aliases)
507 functions[(Name) a] = func;
510 public void DefAlias (string alias, string str)
512 functions[(Name) alias] = functions[(Name) str];
515 internal Function.Lambda RegisterFunction (XmlNode node)
517 Function.Lambda lambda = new Function.Lambda (node, this);
519 functions[lambda.name] = lambda;
523 internal Function Defun (XmlNode node)
525 Name name = node.Attributes[Nfname].Value;
528 if (! functions.TryGetValue (name, out func))
529 func = RegisterFunction (node);
530 ((Function.Lambda) func).SetBody (node, this);
534 public void Defvar (XmlNode node)
536 Name name = node.Attributes[0].Value;
539 node = node.FirstChild;
540 if (node.Name == Ndescription)
541 node = node.NextSibling;
544 Name type = node.Name;
545 XmlNodeList range_list = null;
547 string val = node.InnerText;
549 node = node.NextSibling;
552 range_list = node.ChildNodes;
553 nranges = range_list.Count;
556 if (type == Ninteger)
558 Variable.Int vi = new Variable.Int (name, parse_integer (val));
559 if (range_list != null)
561 vi.ranges = new Variable.Int.Range[nranges];
563 for (int i = 0; i < nranges; i++)
565 XmlNode n = range_list[i];
567 if (n.Name == Nrange)
570 parse_integer (n.FirstChild.InnerText);
572 parse_integer (n.LastChild.InnerText);
576 int num = parse_integer (n.InnerText);
577 vi.ranges[i].from = vi.ranges[i].to = num;
583 else if (type == Nstring)
585 Variable.Str vs = new Variable.Str (name, val);
586 if (range_list != null)
587 vs.ranges = new string[nranges];
588 for (int i = 0; i < nranges; i++)
589 vs.ranges[i] = range_list[i].Value;
593 throw new Exception ("Unknown type: " + type);
596 vari = new Variable.Misc (name, Zero);
597 variables[name] = vari;
600 internal Variable Defvar (Name name)
602 Variable vari = new Variable.Misc (name, Zero);
603 variables[name] = vari;
607 internal Function GetFunc (Name name)
611 if (! functions.TryGetValue (name, out func))
612 throw new Exception ("Unknown function: " + name);
616 public bool CopyFunc (Domain domain, Name name)
618 Function func = GetFunc (name);
620 domain.functions[name] = func;
624 public void CopyFunc (Domain domain)
626 foreach (KeyValuePair<Name, Function> kv in functions)
627 domain.functions[kv.Key] = kv.Value;
630 internal Variable GetVar (Name name)
634 if (! variables.TryGetValue (name, out vari))
635 variables[name] = vari = new Variable.Misc (name, Zero);
639 public override string ToString ()
641 string str = "<(functions";
642 foreach (KeyValuePair<Name, Function> kv in functions)
644 str += ") (variabls";
645 foreach (KeyValuePair<Name, Variable> kv in variables)
648 if (bindings != null)
649 str += " " + bindings;
651 str += " (" + context + ")";
656 internal void DebugWrite (bool head, string fmt, params string[] arg)
658 if (debug_level > depth)
662 Console.WriteLine ();
663 for (int i = 0; i < depth; i++)
666 Console.Write (fmt, arg);
671 public delegate Term Builtin (Domain domain, Variable vari, Term[] args);
673 private static Domain basic = new Domain ();
675 internal static Function Fprogn;
677 static Xexpression ()
679 basic.DefSubr (set_value, "set", true, 1, 1, "=");
680 basic.DefSubr (not, "not", false, 1, 1, "!");
681 basic.DefSubr (add, "add", true, 1, -1, "+");
682 basic.DefSubr (mul, "mul", true, 1, -1, "*");
683 basic.DefSubr (sub, "sub", true, 1, -1, "-");
684 basic.DefSubr (div, "div", true, 1, -1, "/");
685 basic.DefSubr (mod, "mod", true, 1, 2, "%");
686 basic.DefSubr (logior, "logior", true, 1, -1, "|");
687 basic.DefSubr (logand, "logand", true, 1, -1, "&");
688 basic.DefSubr (lsh, "lsh", true, 1, 2, "<<");
689 basic.DefSubr (rsh, "rsh", true, 1, 2, ">>");
690 basic.DefSubr (eq, "eq", false, 2, -1, "==");
691 basic.DefSubr (noteq, "noteq", false, 2, 2, "!=");
692 basic.DefSubr (less_than, "lt", false, 2, -1, "<");
693 basic.DefSubr (less_eq, "le", false, 2, -1, "<=");
694 basic.DefSubr (greater_than, "gt", false, 2, -1, ">");
695 basic.DefSubr (greater_eq, "ge", false, 2, -1, ">=");
696 basic.DefSubr (append, "append", true, 0, -1);
697 basic.DefSubr (concat, "concat", true, 0, -1);
698 basic.DefSubr (nth, "nth", false, 2, 2);
699 basic.DefSubr (copy, "copy", false, 1, 1);
700 basic.DefSubr (ins, "ins", true, 2, 2);
701 basic.DefSubr (del, "del", true, 2, 2);
702 basic.DefSubr (eval_clause, "eval", false, 1, 1);
703 basic.DefSubr (break_clause, "break", false, 0, 1);
704 basic.DefSubr (return_clause, "return", false, 1, 1);
705 basic.DefSpecial (and, "and", 1, -1, "&&");
706 basic.DefSpecial (or, "or", 1, -1, "||");
707 basic.DefSpecial (progn_clause, "progn", 0, -1, "expr");
708 basic.DefSpecial (if_clause, "if", 2, 3);
709 basic.DefSpecial (when_clause, "when", 1, -1);
710 basic.DefSpecial (loop_clause, "loop", 1, -1);
711 basic.DefSpecial (while_clause, "while", 1, -1);
712 basic.DefSpecial (cond_clause, "cond", 1, -1);
713 basic.DefSpecial (foreach_clause, "foreach", 2, -1);
714 basic.DefSpecial (quote_clause, "quote", 1, 1);
715 basic.DefSpecial (type_clause, "type", 1, 1);
717 Fprogn = basic.GetFunc (Nprogn);
720 private static Term set_value (Domain domain, Variable vari, Term[] args)
722 vari.Value = args[0];
726 private static Term not (Domain domain, Variable vari, Term[] args)
728 return args[0].IsTrue ? Zero : One;
731 private static Term add (Domain domain, Variable vari, Term[] args)
733 int n = vari == null ? 0 : vari.val.Intval;
735 foreach (Term arg in args)
743 private static Term mul (Domain domain, Variable vari, Term[] args)
745 int n = vari == null ? 1 : vari.val.Intval;
746 foreach (Term arg in args)
754 private static Term sub (Domain domain, Variable vari, Term[] args)
768 while (i < args.Length)
769 n -= (int) args[i++];
776 private static Term div (Domain domain, Variable vari, Term[] args)
790 while (i < args.Length)
791 n /= args[i++].Intval;
798 private static Term mod (Domain domain, Variable vari, Term[] args)
801 return (args[0].Intval % args[1].Intval);
802 vari.val.intval = vari.val.Intval % args[0].Intval;
806 private static Term logior (Domain domain, Variable vari, Term[] args)
808 int n = vari == null ? 0 : vari.val.Intval;
809 foreach (Term arg in args)
817 private static Term logand (Domain domain, Variable vari, Term[] args)
831 while (i < args.Length)
832 n &= (int) args[i++];
839 private static Term lsh (Domain domain, Variable vari, Term[] args)
842 return args[0].Intval << args[1].Intval;
843 vari.val.intval = vari.val.Intval << args[0].Intval;
847 private static Term rsh (Domain domain, Variable vari, Term[] args)
850 return args[0].Intval >> args[1].Intval;
851 vari.val.intval = vari.val.Intval >> args[0].Intval;
855 private static Term eq (Domain domain, Variable vari, Term[] args)
859 if (o.objval == null)
861 for (int i = 1; i < args.Length; i++)
862 if (args[i].objval != null || args[i].intval != o.intval)
867 for (int i = 1; i < args.Length; i++)
868 if (o.objval.Equals (args[i].objval))
874 private static Term noteq (Domain domain, Variable vari, Term[] args)
876 return eq (domain, vari, args);
879 private static Term less_than (Domain domain, Variable vari, Term[] args)
881 int n = (int) args[0];
883 for (int i = 1; i < args.Length; i++)
885 int n1 = (int) args[i];
893 private static Term less_eq (Domain domain, Variable vari, Term[] args)
895 int n = (int) args[0];
896 for (int i = 1; i < args.Length; i++)
898 int n1 = (int) args[i];
906 private static Term greater_than (Domain domain, Variable vari, Term[] args)
908 int n = (int) args[0];
909 for (int i = 1; i < args.Length; i++)
911 int n1 = (int) args[i];
919 private static Term greater_eq (Domain domain, Variable vari, Term[] args)
921 int n = (int) args[0];
922 for (int i = 1; i < args.Length; i++)
924 int n1 = (int) args[i];
932 private static Term append (Domain domain, Variable vari, Term[] args)
937 list = new List<Term> ();
939 list = vari.val.Listval;
941 foreach (Term arg in args)
944 list.AddRange ((List<Term>) arg.objval);
952 result.objval = list;
955 vari.val.objval = list;
959 private static Term concat (Domain domain, Variable vari, Term[] args)
966 str = vari.val.Strval;
968 foreach (Term arg in args)
971 str += (string) arg.objval;
973 foreach (Term term in (List<Term>) arg.objval)
974 str += (char) term.Intval;
976 str += (char) arg.Intval;
985 vari.val.objval = str;
989 private static Term nth (Domain domain, Variable vari, Term[] args)
995 result.intval = ((string) args[1].objval)[args[0].Intval];
996 result.objval = null;
998 else if (args[1].IsList)
1000 result = ((List<Term>) args[1].objval)[args[0].Intval];
1003 throw new Exception ("Term is not enumelable: " + args[1]);
1007 private static Term copy (Domain domain, Variable vari, Term[] args)
1012 result.objval = new List<Term> (args[0].Listval);
1016 private static Term ins (Domain domain, Variable vari, Term[] args)
1020 = vari.val.Strval.Insert (args[0].Intval, args[1].Strval);
1021 else if (vari.val.IsList)
1022 vari.val.Listval.InsertRange (args[0].Intval, args[1].Listval);
1024 throw new Exception ("term is not collection: " + vari.val);
1028 private static Term del (Domain domain, Variable vari, Term[] args)
1032 = vari.val.Strval.Remove (args[0].Intval,
1033 args[1].Intval - args[0].Intval);
1035 else if (vari.val.IsList)
1036 vari.val.Listval.RemoveRange (args[0].Intval,
1037 args[1].Intval - args[0].Intval);
1039 throw new Exception ("term is not collection: " + vari.val);
1043 private static Term and (Domain domain, Variable vari, Term[] args)
1045 foreach (Term arg in args)
1046 if (! arg.Eval (domain).IsTrue)
1051 private static Term or (Domain domain, Variable vari, Term[] args)
1053 foreach (Term arg in args)
1054 if (arg.Eval (domain).IsTrue)
1059 private static Term eval_clause (Domain domain, Variable vari, Term[] args)
1061 return (args[0].Eval (domain));
1064 private static Term progn_clause (Domain domain, Variable vari, Term[] args)
1068 foreach (Term arg in args)
1069 result = arg.Eval (domain);
1073 private static Term if_clause (Domain domain, Variable vari, Term[] args)
1075 if (args[0].Eval (domain).IsTrue)
1076 return args[1].Eval (domain);
1077 if (args.Length == 2)
1079 return args[2].Eval (domain);
1082 private static Term when_clause (Domain domain, Variable vari, Term[] args)
1084 if (! args[0].Eval (domain).IsTrue)
1087 for (int i = 1; i < args.Length; i++)
1088 result = args[i].Eval (domain);
1092 private static Term return_clause (Domain domain, Variable vari, Term[] args)
1094 domain.ThrowReturn ();
1095 return args.Length == 0 ? Zero : args[0];
1098 private static Term break_clause (Domain domain, Variable vari, Term[] args)
1100 domain.ThrowBreak ();
1101 return args.Length == 0 ? Zero : args[0];
1104 private static Term loop_clause (Domain domain, Variable vari, Term[] args)
1108 domain.Catch (Nbreak);
1109 while (! domain.Catched)
1110 foreach (Term arg in args)
1112 result = arg.Eval (domain);
1122 private static Term while_clause (Domain domain, Variable vari, Term[] args)
1126 domain.Catch (Nbreak);
1127 while (! domain.Catched && args[0].Eval (domain).IsTrue)
1128 for (int i = 1; i < args.Length; i++)
1130 result = args[i].Eval (domain);
1140 private static Term cond_clause (Domain domain, Variable vari, Term[] args)
1142 foreach (Term arg in args)
1144 List<Term> list = arg.Listval;
1145 Term result = list[0].Eval (domain);
1149 for (int i = 1; i < list.Count; i++)
1150 result = list[i].Eval (domain);
1157 private static Term foreach_clause (Domain domain, Variable vari,
1160 List<Term> list = args[0].Eval (domain).Listval;
1161 Bindings current = domain.bindings;
1165 domain.Catch (Nbreak);
1166 foreach (Term term in list)
1168 domain.Bind (vari, term);
1170 for (int i = 1; i < args.Length; i++)
1172 result = args[i].Eval (domain);
1177 domain.UnboundTo (current);
1188 private static Term quote_clause (Domain domain, Variable vari, Term[] args)
1190 return new Term (args[0]);
1193 private static Term type_clause (Domain domain, Variable vari, Term[] args)
1209 public object objval;
1211 public Term (int i) { intval = i; objval = null; }
1212 public Term (Name name) { intval = 0; objval = name; }
1213 public Term (string str) { intval = 0; objval = str; }
1214 public Term (List<Term> list) { intval = 0; objval = list; }
1215 public Term (Term term) { intval = 0; objval = term; }
1217 public Term (XmlNode node, Domain domain)
1219 Name name = node.Name;
1221 if (name == Ninteger)
1223 intval = parse_integer (node.InnerText);
1229 if (name == Nsymbol)
1230 objval = (Name) node.InnerText;
1231 else if (name == Nstring)
1232 objval = node.InnerText.Clone ();
1233 else if (name == Nvarref)
1234 objval = domain.GetVar ((Name) node.Attributes[0].Value);
1235 else if (name == Nlist)
1237 List<Term> list = new List<Term> ();
1238 for (node = node.FirstChild; node != null;
1239 node = node.NextSibling)
1240 list.Add (new Term (node, domain));
1246 Variable vari = null;
1249 if (name == Nfuncall)
1250 name = node.Attributes[0].Value;
1251 else if (node.Attributes[Nvname] != null)
1252 vari = domain.GetVar (node.Attributes[Nvname].Value);
1253 func = domain.GetFunc (name);
1254 XmlNodeList nlist = node.ChildNodes;
1255 int nargs = nlist.Count;
1257 if (nargs < func.min_arg
1258 || (func.max_arg >= 0 && nargs > func.max_arg))
1259 throw new Exception ("Invalid number of arguments to: "
1260 + name + " " + nargs);
1261 args = new Term[nargs];
1262 for (int i = 0; i < nlist.Count; i++)
1263 args[i] = new Term (nlist[i], domain);
1264 objval = new Funcall (func, vari, args);
1269 private class Funcall
1271 internal Function func;
1272 internal Variable vari;
1273 internal Term[] args;
1275 public Funcall (Function func, Variable vari, Term[] args)
1282 public Term Eval (Domain domain)
1284 domain.DebugWrite (true, "(({0}", func.name);
1285 for (int i = 0; i < args.Length; i++)
1286 domain.DebugWrite (false, " {0}", args[i].ToString ());
1287 domain.DebugWrite (false, ")");
1289 Term result = func.Call (domain, vari, args);
1291 domain.DebugWrite (true, " ==> {0})", result.ToString ());
1295 public override string ToString ()
1297 string str = "<funcall fname=\"" + func.name;
1299 return str + "\"/>";
1301 foreach (Term e in args)
1303 return (str + "</funcall>");
1310 throw new Exception ("term is not integer: " + this);
1315 public string Strval {
1318 throw new Exception ("term is not string: " + this);
1319 return (string) objval;
1323 public List<Term> Listval {
1326 throw new Exception ("term is not list: " + this);
1327 return (List<Term>) objval;
1331 public bool IsTrue {
1333 return (objval == null
1335 : objval is List<Term>
1336 ? (((List<Term>) objval).Count != 0)
1340 public bool IsInt { get { return (objval == null); } }
1341 public bool IsStr { get { return (objval is string); } }
1342 public bool IsName { get { return (objval is Name); } }
1343 public bool IsList { get { return (objval is List<Term>); } }
1345 public Term Eval (Domain domain)
1347 if (objval == null || objval is Name || objval is string)
1349 if (objval is List<Term>)
1350 return new Term ((List<Term>) objval);
1351 if (objval is Funcall)
1352 return ((Funcall) objval).Eval (domain);
1353 if (objval is Variable)
1354 return ((Variable) objval).val;
1356 return (Term) objval;
1357 throw new Exception ("invalid Term object: " + objval);
1360 public static explicit operator int (Term term)
1362 if (term.objval != null)
1363 throw new Exception ("Not an integer term: " + term);
1367 public static explicit operator Name (Term term)
1369 return (Name) term.objval;
1372 public static implicit operator Term (int i)
1374 return new Term (i);
1377 public override string ToString ()
1382 str = "<integer>" + intval + "</integer>";
1383 else if (objval is Name)
1384 str = "<symbol>" + objval + "</symbol>";
1385 else if (objval is string)
1386 str = "<string>" + objval + "</string>";
1387 else if (objval is List<Term>)
1390 foreach (Term e in (List<Term>) objval)
1394 else if (objval is Funcall)
1395 str = "<funcall fname=\"" + ((Funcall) objval).func.name + "\"/>";
1396 else if (objval is Variable)
1397 str = "<variable vname=\"" + ((Variable) objval).name + "\"/>";
1398 else if (objval is Term)
1399 str = "<quote>" + objval + "</quote>";
1401 throw new Exception ("invalid Term object: " + objval);
1406 static Term Zero = new Term (0);
1407 static Term One = new Term (1);
1408 static Term TermInt = new Term (Ninteger);
1409 static Term TermStr = new Term (Nstring);
1410 static Term TermName = new Term (Nsymbol);
1411 static Term TermList = new Term (Nlist);
1412 static Term TermTerm = new Term ((Name) "term");
1414 internal static int parse_integer (string str)
1416 int len = str.Length;
1417 bool negative = false;
1420 return (len == 0 ? 0 : str[0] - '0');
1425 if (c == '0' && str[1] == 'x')
1428 for (int idx = 2; idx < len; idx++)
1434 i = i * 16 + (c - '0');
1438 i = i * 16 + (c - 'A');
1442 i = i * 16 + (c - 'a');
1451 for (int idx = 1; idx < len; idx++)
1454 if (c < '0' || c > '9')
1456 i = i * 10 + (c - '0');
1458 return negative ? - i : i;
1461 private Term[] terms;
1463 public Xexpression (string url, Domain domain)
1465 XmlDocument doc = new XmlDocument (Name.Table);
1468 using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
1472 } while (reader.NodeType != XmlNodeType.None
1473 && (reader.NodeType != XmlNodeType.Element
1474 || reader.Name != Nexpr));
1475 if (reader.NodeType == XmlNodeType.None)
1476 throw new Exception ("Node <expr> not found");
1477 node = doc.ReadNode (reader);
1481 for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
1482 if (n.NodeType == XmlNodeType.Element)
1484 if (n.Name == Ndefun)
1485 domain.RegisterFunction (n);
1486 else if (n.Name == Ndefvar)
1492 terms = new Term[nterms];
1494 for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
1495 if (n.NodeType == XmlNodeType.Element)
1497 if (n.Name == Ndefun)
1499 else if (n.Name != Ndefvar)
1500 terms[i++]= new Term (n, domain);
1504 public Term Eval (Domain domain)
1510 domain.Catch (Nreturn);
1511 foreach (Term term in terms)
1513 result = term.Eval (domain);
1523 public override string ToString ()
1526 for (int i = 0; i < terms.Length; i++)