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 Nloop = "loop";
108 private static Name Nfunction = "function";
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++)
148 newargs[i] = args[i].Eval (domain);
149 return builtin (domain, vari, newargs);
153 internal class SpecialForm : Function
155 public Builtin builtin;
157 public SpecialForm (Builtin builtin, Name name,
158 int min_arg, int max_arg)
159 : base (name, min_arg, max_arg)
161 this.builtin = builtin;
164 public override Term Call (Domain domain, Variable vari, Term[] args)
166 return builtin (domain, vari, args);
170 internal class Lambda : Function
172 internal bool args_evalled;
173 internal Variable[] args;
174 internal Term[] body;
176 public Lambda (XmlNode node, Domain domain)
181 name = node.Attributes[Nfname].Value;
183 node = node.FirstChild;
185 && (node.Name == Nargs || node.Name == Nargs_unevalled))
188 args_evalled = node.Name == Nargs;
189 for (n = node.FirstChild; n != null; n = n.NextSibling)
191 if (n.Name == Nfixed)
193 else if (n.Name == Noptional)
195 else if (n.Name == Nrest)
198 throw new Exception ("Invalid argument type: " + n);
201 max_arg = nfixed + noptional + nrest;
202 args = new Variable[max_arg];
204 for (int i = 0; i < max_arg; n = n.NextSibling)
205 args[i++] = domain.Defvar ((Name) n.Attributes[0].Value);
211 min_arg = max_arg = 0;
215 public void SetBody (XmlNode node, Domain domain)
217 for (node = node.FirstChild; node != null; node = node.NextSibling)
218 if (node.Name != Ndescription
219 && node.Name != Nargs
220 && node.Name != Nargs_unevalled)
223 for (XmlNode n = node; n != null; n = n.NextSibling)
227 body = new Term[nterms];
228 for (nterms = 0; node != null; node = node.NextSibling, nterms++)
229 body[nterms] = new Term (node, domain);
233 public override Term Call (Domain domain, Variable vari, Term[] args)
235 Bindings current = domain.bindings;
242 Term[] newargs = new Term[args.Length];
243 for (i = 0; i < min_arg; i++)
244 newargs[i] = args[i].Eval (domain);
247 for (i = 0; i < min_arg; i++)
248 domain.Bind (this.args[i], args[i]);
250 foreach (Term term in body)
251 result = term.Eval (domain);
253 domain.UnboundTo (current);
260 public abstract class Variable
262 public readonly Name name;
265 public Variable (Name name, Term term)
276 if (! ValueP (value))
277 throw new Exception ("Invalid value of " + name + ": " + value);
282 public abstract bool ValueP (Term term);
284 public override string ToString () { return name + "(" + val + ")"; }
286 internal class Int : Variable
293 public Range[] ranges;
295 public Int (Name name, int i) : base (name, new Term (i)) { }
297 public override bool ValueP (Term term)
301 if (term.objval != null)
306 foreach (Range r in ranges)
307 if (i >= r.from && i <= r.to)
313 internal class Str : Variable
315 public string[] ranges;
317 public Str (Name name, string str) : base (name, new Term (str)) { }
319 public override bool ValueP (Term term)
321 if (! (term.objval is string))
325 string str = (string) term.objval;
326 foreach (string s in ranges)
333 internal class Misc : Variable
335 public Misc (Name name, Term term) : base (name, term) { }
337 public override bool ValueP (Term term) { return true; }
341 internal class Bindings
343 private Variable vari;
344 private Term old_value;
345 private Bindings next;
347 private Bindings (Variable vari)
350 old_value = vari.val;
353 public static Bindings Bind (Bindings bindings, Variable vari, Term val)
355 Bindings b = new Bindings (vari);
362 internal Bindings UnboundTo (Bindings boundary)
364 for (Bindings b = this; b != boundary; b = b.next)
365 b.vari.val = b.old_value;
369 public override string ToString ()
371 string str = "(bindings";
372 for (Bindings b = this; b != null; b = b.next)
373 str += " " + vari.name + "=" + b.old_value;
379 internal class ThrowException : Exception
384 public ThrowException (Name tag, object value) : base ()
392 internal struct CatchTag
394 public readonly Name name;
395 public readonly int count;
397 public CatchTag (Name name, int count)
406 public object context;
407 public int depth = 0;
409 internal Dictionary<Name, Function> functions;
410 internal Dictionary<Name, Variable> variables;
411 internal Bindings bindings;
412 internal Stack<CatchTag> catch_list = new Stack<CatchTag> ();
413 private int catch_count = 0;
417 functions = new Dictionary<Name, Function> ();
418 variables = new Dictionary<Name, Variable> ();
421 public Domain (object context) : this (basic, context)
425 public Domain (Domain parent, object context)
427 functions = new Dictionary<Name, Function> (parent.functions);
428 variables = new Dictionary<Name, Variable> (parent.variables);
429 this.context = context;
432 internal void Bind (Variable vari, Term value)
434 bindings = Bindings.Bind (bindings, vari, value);
437 internal void UnboundTo (Bindings boundary)
439 if (bindings != null)
440 bindings = bindings.UnboundTo (boundary);
443 internal void Catch (Name name)
445 catch_list.Push (new CatchTag (name, catchcount++));
448 internal bool Catched {
449 get { return catch_list.Peek ().count == catchcount; }
452 internal void ThrowReturn ()
454 catch_list.Peek ().count = catchcount;
457 internal void ThrowBreak ()
459 catch_list.Peek ().count = catchcount;
462 internal void Uncatch ()
467 public void DefSubr (Builtin builtin, string str, bool setvar,
468 int min_arg, int max_arg, params string[] aliases)
471 Function func = new Function.Subroutine (builtin, name, setvar,
473 functions[name] = func;
474 foreach (string a in aliases)
475 functions[(Name) a] = func;
478 public void DefSpecial (Builtin builtin, string str,
479 int min_arg, int max_arg,
480 params string[] aliases)
483 Function func = new Function.SpecialForm (builtin, name,
485 functions[name] = func;
486 foreach (string a in aliases)
487 functions[(Name) a] = func;
490 public void DefAlias (string alias, string str)
492 functions[(Name) alias] = functions[(Name) str];
495 internal Function.Lambda RegisterFunction (XmlNode node)
497 Function.Lambda lambda = new Function.Lambda (node, this);
499 functions[lambda.name] = lambda;
503 internal Function Defun (XmlNode node)
505 Name name = node.Attributes[Nfname].Value;
508 if (! functions.TryGetValue (name, out func))
509 func = RegisterFunction (node);
510 ((Function.Lambda) func).SetBody (node, this);
514 public void Defvar (XmlNode node)
516 Name name = node.Attributes[0].Value;
519 node = node.FirstChild;
520 if (node.Name == Ndescription)
521 node = node.NextSibling;
524 Name type = node.Name;
525 XmlNodeList range_list = null;
527 string val = node.InnerText;
529 node = node.NextSibling;
532 range_list = node.ChildNodes;
533 nranges = range_list.Count;
536 if (type == Ninteger)
538 Variable.Int vi = new Variable.Int (name, parse_integer (val));
539 if (range_list != null)
541 vi.ranges = new Variable.Int.Range[nranges];
543 for (int i = 0; i < nranges; i++)
545 XmlNode n = range_list[i];
547 if (n.Name == Nrange)
550 parse_integer (n.FirstChild.InnerText);
552 parse_integer (n.LastChild.InnerText);
556 int num = parse_integer (n.InnerText);
557 vi.ranges[i].from = vi.ranges[i].to = num;
563 else if (type == Nstring)
565 Variable.Str vs = new Variable.Str (name, val);
566 if (range_list != null)
567 vs.ranges = new string[nranges];
568 for (int i = 0; i < nranges; i++)
569 vs.ranges[i] = range_list[i].Value;
573 throw new Exception ("Unknown type: " + type);
576 vari = new Variable.Misc (name, Zero);
577 variables[name] = vari;
580 internal Variable Defvar (Name name)
582 Variable vari = new Variable.Misc (name, Zero);
583 variables[name] = vari;
587 internal Function GetFunc (Name name)
591 if (! functions.TryGetValue (name, out func))
592 throw new Exception ("Unknown function: " + name);
596 public bool CopyFunc (Domain domain, Name name)
598 Function func = GetFunc (name);
600 domain.functions[name] = func;
604 public void CopyFunc (Domain domain)
606 foreach (KeyValuePair<Name, Function> kv in functions)
607 domain.functions[kv.Key] = kv.Value;
610 internal Variable GetVar (Name name)
614 if (! variables.TryGetValue (name, out vari))
615 variables[name] = vari = new Variable.Misc (name, Zero);
619 public override string ToString ()
621 string str = "<(functions";
622 foreach (KeyValuePair<Name, Function> kv in functions)
624 str += ") (variabls";
625 foreach (KeyValuePair<Name, Variable> kv in variables)
628 if (bindings != null)
629 str += " " + bindings;
631 str += " (" + context + ")";
636 internal void DebugWrite (bool head, string fmt, params string[] arg)
638 if (debug_level > depth)
642 Console.WriteLine ();
643 for (int i = 0; i < depth; i++)
646 Console.Write (fmt, arg);
651 public delegate Term Builtin (Domain domain, Variable vari, Term[] args);
653 private static Domain basic = new Domain ();
655 internal static Function Fprogn;
657 static Xexpression ()
659 basic.DefSubr (set_value, "set", true, 1, 1, "=");
660 basic.DefSubr (not, "not", false, 1, 1, "!");
661 basic.DefSubr (add, "add", true, 1, -1, "+");
662 basic.DefSubr (mul, "mul", true, 1, -1, "*");
663 basic.DefSubr (sub, "sub", true, 1, -1, "-");
664 basic.DefSubr (div, "div", true, 1, -1, "/");
665 basic.DefSubr (mod, "mod", true, 1, 2, "%");
666 basic.DefSubr (logior, "logior", true, 1, -1, "|");
667 basic.DefSubr (logand, "logand", true, 1, -1, "&");
668 basic.DefSubr (lsh, "lsh", true, 1, 2, "<<");
669 basic.DefSubr (rsh, "rsh", true, 1, 2, ">>");
670 basic.DefSubr (eq, "eq", false, 2, -1, "==");
671 basic.DefSubr (noteq, "noteq", false, 2, 2, "!=");
672 basic.DefSubr (less_than, "lt", false, 2, -1, "<");
673 basic.DefSubr (less_eq, "le", false, 2, -1, "<=");
674 basic.DefSubr (greater_than, "gt", false, 2, -1, ">");
675 basic.DefSubr (greater_eq, "ge", false, 2, -1, ">=");
676 basic.DefSubr (append, "append", true, 0, -1);
677 basic.DefSubr (concat, "concat", true, 0, -1);
678 basic.DefSubr (nth, "nth", false, 2, 2);
679 basic.DefSubr (copy, "copy", false, 1, 1);
680 basic.DefSubr (ins, "ins", true, 2, 2);
681 basic.DefSubr (del, "del", true, 2, 2);
682 basic.DefSubr (eval_clause, "eval", false, 1, 1);
683 basic.DefSubr (break_clause, "break", false, 0, 1);
684 basic.DefSubr (return_clause, "return", false, 1, 1);
685 basic.DefSpecial (and, "and", 1, -1, "&&");
686 basic.DefSpecial (or, "or", 1, -1, "||");
687 basic.DefSpecial (progn_clause, "progn", 0, -1, "expr");
688 basic.DefSpecial (if_clause, "if", 2, 3);
689 basic.DefSpecial (when_clause, "when", 1, -1);
690 basic.DefSpecial (loop_clause, "loop", 1, -1);
691 basic.DefSpecial (while_clause, "while", 1, -1);
692 basic.DefSpecial (cond_clause, "cond", 1, -1);
693 basic.DefSpecial (foreach_clause, "foreach", 2, -1);
694 basic.DefSpecial (quote_clause, "quote", 1, 1);
695 basic.DefSpecial (type_clause, "type", 1, 1);
697 Fprogn = basic.GetFunc (Nprogn);
700 private static Term set_value (Domain domain, Variable vari, Term[] args)
702 vari.Value = args[0];
706 private static Term not (Domain domain, Variable vari, Term[] args)
708 return args[0].IsTrue ? Zero : One;
711 private static Term add (Domain domain, Variable vari, Term[] args)
713 int n = vari == null ? 0 : vari.val.Intval;
715 foreach (Term arg in args)
723 private static Term mul (Domain domain, Variable vari, Term[] args)
725 int n = vari == null ? 1 : vari.val.Intval;
726 foreach (Term arg in args)
734 private static Term sub (Domain domain, Variable vari, Term[] args)
748 while (i < args.Length)
749 n -= (int) args[i++];
756 private static Term div (Domain domain, Variable vari, Term[] args)
770 while (i < args.Length)
771 n /= args[i++].Intval;
778 private static Term mod (Domain domain, Variable vari, Term[] args)
781 return (args[0].Intval % args[1].Intval);
782 vari.val.intval = vari.val.Intval % args[0].Intval;
786 private static Term logior (Domain domain, Variable vari, Term[] args)
788 int n = vari == null ? 0 : vari.val.Intval;
789 foreach (Term arg in args)
797 private static Term logand (Domain domain, Variable vari, Term[] args)
811 while (i < args.Length)
812 n &= (int) args[i++];
819 private static Term lsh (Domain domain, Variable vari, Term[] args)
822 return args[0].Intval << args[1].Intval;
823 vari.val.intval = vari.val.Intval << args[0].Intval;
827 private static Term rsh (Domain domain, Variable vari, Term[] args)
830 return args[0].Intval >> args[1].Intval;
831 vari.val.intval = vari.val.Intval >> args[0].Intval;
835 private static Term eq (Domain domain, Variable vari, Term[] args)
839 if (o.objval == null)
841 for (int i = 1; i < args.Length; i++)
842 if (args[i].objval != null || args[i].intval != o.intval)
847 for (int i = 1; i < args.Length; i++)
848 if (o.objval.Equals (args[i].objval))
854 private static Term noteq (Domain domain, Variable vari, Term[] args)
856 return eq (domain, vari, args);
859 private static Term less_than (Domain domain, Variable vari, Term[] args)
861 int n = (int) args[0];
863 for (int i = 1; i < args.Length; i++)
865 int n1 = (int) args[i];
873 private static Term less_eq (Domain domain, Variable vari, Term[] args)
875 int n = (int) args[0];
876 for (int i = 1; i < args.Length; i++)
878 int n1 = (int) args[i];
886 private static Term greater_than (Domain domain, Variable vari, Term[] args)
888 int n = (int) args[0];
889 for (int i = 1; i < args.Length; i++)
891 int n1 = (int) args[i];
899 private static Term greater_eq (Domain domain, Variable vari, Term[] args)
901 int n = (int) args[0];
902 for (int i = 1; i < args.Length; i++)
904 int n1 = (int) args[i];
912 private static Term append (Domain domain, Variable vari, Term[] args)
917 list = new List<Term> ();
919 list = vari.val.Listval;
921 foreach (Term arg in args)
924 list.AddRange ((List<Term>) arg.objval);
932 result.objval = list;
935 vari.val.objval = list;
939 private static Term concat (Domain domain, Variable vari, Term[] args)
946 str = vari.val.Strval;
948 foreach (Term arg in args)
951 str += (string) arg.objval;
953 foreach (Term term in (List<Term>) arg.objval)
954 str += (char) term.Intval;
956 str += (char) arg.Intval;
965 vari.val.objval = str;
969 private static Term nth (Domain domain, Variable vari, Term[] args)
975 result.intval = ((string) args[1].objval)[args[0].Intval];
976 result.objval = null;
978 else if (args[1].IsList)
980 result = ((List<Term>) args[1].objval)[args[0].Intval];
983 throw new Exception ("Term is not enumelable: " + args[1]);
987 private static Term copy (Domain domain, Variable vari, Term[] args)
992 result.objval = new List<Term> (args[0].Listval);
996 private static Term ins (Domain domain, Variable vari, Term[] args)
1000 = vari.val.Strval.Insert (args[0].Intval, args[1].Strval);
1001 else if (vari.val.IsList)
1002 vari.val.Listval.InsertRange (args[0].Intval, args[1].Listval);
1004 throw new Exception ("term is not collection: " + vari.val);
1008 private static Term del (Domain domain, Variable vari, Term[] args)
1012 = vari.val.Strval.Remove (args[0].Intval,
1013 args[1].Intval - args[0].Intval);
1015 else if (vari.val.IsList)
1016 vari.val.Listval.RemoveRange (args[0].Intval,
1017 args[1].Intval - args[0].Intval);
1019 throw new Exception ("term is not collection: " + vari.val);
1023 private static Term and (Domain domain, Variable vari, Term[] args)
1025 foreach (Term arg in args)
1026 if (! arg.Eval (domain).IsTrue)
1031 private static Term or (Domain domain, Variable vari, Term[] args)
1033 foreach (Term arg in args)
1034 if (arg.Eval (domain).IsTrue)
1039 private static Term eval_clause (Domain domain, Variable vari, Term[] args)
1041 return (args[0].Eval (domain));
1044 private static Term progn_clause (Domain domain, Variable vari, Term[] args)
1048 foreach (Term arg in args)
1049 result = arg.Eval (domain);
1053 private static Term if_clause (Domain domain, Variable vari, Term[] args)
1055 if (args[0].Eval (domain).IsTrue)
1056 return args[1].Eval (domain);
1057 if (args.Length == 2)
1059 return args[2].Eval (domain);
1062 private static Term when_clause (Domain domain, Variable vari, Term[] args)
1064 if (! args[0].Eval (domain).IsTrue)
1067 for (int i = 1; i < args.Length; i++)
1068 result = args[i].Eval (domain);
1072 private static Term break_clause (Domain domain, Variable vari, Term[] args)
1074 Stack<CatchTag> clist = domain.catch_list;
1075 if (clist.Count == 0)
1076 throw new Exception ("No outer loop to break");
1077 CatchTag tag = clist.Peek ();
1078 if (tag.name != Nloop)
1079 throw new Exception ("No outer loop to break");
1080 domain.depth = tag.depth;
1081 return args.Length == 0 ? Zero : args[0];
1084 private static Term return_clause (Domain domain, Variable vari, Term[] args)
1086 Stack<CatchTag> clist = domain.catch_list;
1088 while (clist.Count > 0)
1090 CatchTag tag = clist.Pop ();
1091 if (tag.name == Nfunction)
1093 domain.depth = tag.depth;
1094 return = args.Length == 0 ? Zero : args[0];
1097 return args.Length == 0 ? Zero : args[0];
1100 private static Term loop_clause (Domain domain, Variable vari, Term[] args)
1102 domain.Catch (Nloop);
1105 while (! domain.Catched)
1106 foreach (Term arg in args)
1108 result = arg.Eval (domain);
1118 private static Term while_clause (Domain domain, Variable vari, Term[] args)
1120 while (args[0].Eval (domain).IsTrue)
1121 for (int i = 1; i < args.Length; i++)
1122 args[i].Eval (domain);
1126 private static Term cond_clause (Domain domain, Variable vari, Term[] args)
1128 foreach (Term arg in args)
1130 List<Term> list = arg.Listval;
1131 Term result = list[0].Eval (domain);
1135 for (int i = 1; i < list.Count; i++)
1136 result = list[i].Eval (domain);
1143 private static Term foreach_clause (Domain domain, Variable vari,
1146 List<Term> list = args[0].Listval;
1147 Bindings current = domain.bindings;
1149 foreach (Term term in list)
1151 domain.Bind (vari, term);
1153 for (int i = 1; i < args.Length; i++)
1154 args[i].Eval (domain);
1156 domain.UnboundTo (current);
1162 private static Term quote_clause (Domain domain, Variable vari, Term[] args)
1164 return new Term (args[0]);
1167 private static Term type_clause (Domain domain, Variable vari, Term[] args)
1183 public object objval;
1185 public Term (int i) { intval = i; objval = null; }
1186 public Term (Name name) { intval = 0; objval = name; }
1187 public Term (string str) { intval = 0; objval = str; }
1188 public Term (List<Term> list) { intval = 0; objval = list; }
1189 public Term (Term term) { intval = 0; objval = term; }
1191 public Term (XmlNode node, Domain domain)
1193 Name name = node.Name;
1195 if (name == Ninteger)
1197 intval = parse_integer (node.InnerText);
1203 if (name == Nsymbol)
1204 objval = (Name) node.InnerText;
1205 else if (name == Nstring)
1206 objval = node.InnerText.Clone ();
1207 else if (name == Nvarref)
1208 objval = domain.GetVar ((Name) node.Attributes[0].Value);
1209 else if (name == Nlist)
1211 List<Term> list = new List<Term> ();
1212 for (node = node.FirstChild; node != null;
1213 node = node.NextSibling)
1214 list.Add (new Term (node, domain));
1220 Variable vari = null;
1223 if (name == Nfuncall)
1224 name = node.Attributes[0].Value;
1225 else if (node.Attributes[Nvname] != null)
1226 vari = domain.GetVar (node.Attributes[Nvname].Value);
1227 func = domain.GetFunc (name);
1228 XmlNodeList nlist = node.ChildNodes;
1229 int nargs = nlist.Count;
1231 if (nargs < func.min_arg
1232 || (func.max_arg >= 0 && nargs > func.max_arg))
1233 throw new Exception ("Invalid number of arguments to: "
1234 + name + " " + nargs);
1235 args = new Term[nargs];
1236 for (int i = 0; i < nlist.Count; i++)
1237 args[i] = new Term (nlist[i], domain);
1238 objval = new Funcall (func, vari, args);
1243 private class Funcall
1245 internal Function func;
1246 internal Variable vari;
1247 internal Term[] args;
1249 public Funcall (Function func, Variable vari, Term[] args)
1256 public Term Eval (Domain domain)
1258 domain.DebugWrite (true, "(({0}", func.name);
1259 for (int i = 0; i < args.Length; i++)
1260 domain.DebugWrite (false, " {0}", args[i].ToString ());
1261 domain.DebugWrite (false, ")");
1263 Term result = func.Call (domain, vari, args);
1265 domain.DebugWrite (true, " ==> {0})", result.ToString ());
1269 public override string ToString ()
1271 string str = "<funcall fname=\"" + func.name;
1273 return str + "\"/>";
1275 foreach (Term e in args)
1277 return (str + "</funcall>");
1284 throw new Exception ("term is not integer: " + this);
1289 public string Strval {
1292 throw new Exception ("term is not string: " + this);
1293 return (string) objval;
1297 public List<Term> Listval {
1300 throw new Exception ("term is not list: " + this);
1301 return (List<Term>) objval;
1305 public bool IsTrue {
1307 return (objval == null
1309 : objval is List<Term>
1310 ? (((List<Term>) objval).Count != 0)
1314 public bool IsInt { get { return (objval == null); } }
1315 public bool IsStr { get { return (objval is string); } }
1316 public bool IsName { get { return (objval is Name); } }
1317 public bool IsList { get { return (objval is List<Term>); } }
1319 public Term Eval (Domain domain)
1321 if (objval == null || objval is Name || objval is string)
1323 if (objval is List<Term>)
1324 return new Term ((List<Term>) objval);
1325 if (objval is Funcall)
1326 return ((Funcall) objval).Eval (domain);
1327 if (objval is Variable)
1328 return ((Variable) objval).val;
1330 return (Term) objval;
1331 throw new Exception ("invalid Term object: " + objval);
1334 public static explicit operator int (Term term)
1336 if (term.objval != null)
1337 throw new Exception ("Not an integer term: " + term);
1341 public static explicit operator Name (Term term)
1343 return (Name) term.objval;
1346 public static implicit operator Term (int i)
1348 return new Term (i);
1351 public override string ToString ()
1356 str = "<integer>" + intval + "</integer>";
1357 else if (objval is Name)
1358 str = "<symbol>" + objval + "</symbol>";
1359 else if (objval is string)
1360 str = "<string>" + objval + "</string>";
1361 else if (objval is List<Term>)
1364 foreach (Term e in (List<Term>) objval)
1368 else if (objval is Funcall)
1369 str = "<funcall fname=\"" + ((Funcall) objval).func.name + "\"/>";
1370 else if (objval is Variable)
1371 str = "<variable vname=\"" + ((Variable) objval).name + "\"/>";
1372 else if (objval is Term)
1373 str = "<quote>" + objval + "</quote>";
1375 throw new Exception ("invalid Term object: " + objval);
1380 static Term Zero = new Term (0);
1381 static Term One = new Term (1);
1382 static Term TermInt = new Term (Ninteger);
1383 static Term TermStr = new Term (Nstring);
1384 static Term TermName = new Term (Nsymbol);
1385 static Term TermList = new Term (Nlist);
1386 static Term TermTerm = new Term ((Name) "term");
1388 internal static int parse_integer (string str)
1390 int len = str.Length;
1391 bool negative = false;
1394 return (len == 0 ? 0 : str[0] - '0');
1399 if (c == '0' && str[1] == 'x')
1402 for (int idx = 2; idx < len; idx++)
1408 i = i * 16 + (c - '0');
1412 i = i * 16 + (c - 'A');
1416 i = i * 16 + (c - 'a');
1425 for (int idx = 1; idx < len; idx++)
1428 if (c < '0' || c > '9')
1430 i = i * 10 + (c - '0');
1432 return negative ? - i : i;
1435 private Term[] terms;
1437 public Xexpression (string url, Domain domain)
1439 XmlDocument doc = new XmlDocument (Name.Table);
1442 using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
1446 } while (reader.NodeType != XmlNodeType.None
1447 && (reader.NodeType != XmlNodeType.Element
1448 || reader.Name != Nexpr));
1449 if (reader.NodeType == XmlNodeType.None)
1450 throw new Exception ("Node <expr> not found");
1451 node = doc.ReadNode (reader);
1455 for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
1456 if (n.NodeType == XmlNodeType.Element)
1458 if (n.Name == Ndefun)
1459 domain.RegisterFunction (n);
1460 else if (n.Name == Ndefvar)
1466 terms = new Term[nterms];
1468 for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
1469 if (n.NodeType == XmlNodeType.Element)
1471 if (n.Name == Ndefun)
1473 else if (n.Name != Ndefvar)
1474 terms[i++]= new Term (n, domain);
1478 public Term Eval (Domain domain)
1483 foreach (Term term in terms)
1484 result = term.Eval (domain);
1488 public override string ToString ()
1491 for (int i = 0; i < terms.Length; i++)