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 Symbol : IEquatable<Symbol>
15 private static NameTable nt = new NameTable ();
19 public Symbol (string str)
24 public static implicit operator Symbol (string str)
26 return new Symbol (str);
29 public static implicit operator string (Symbol name)
34 public static bool operator== (Symbol n1, Symbol n2)
36 return (object) n1.name == (object) n2.name;
39 public static bool operator!= (Symbol n1, Symbol n2)
41 return (object) n1.name != (object) n2.name;
44 public static bool operator== (Symbol n1, string n2)
46 return (object) n1.name == (object) n2;
49 public static bool operator!= (Symbol n1, string n2)
51 return (object) n1.name != (object) n2;
54 public static bool operator== (string n1, Symbol n2)
56 return (object) n1 == (object) n2.name;
59 public static bool operator!= (string n1, Symbol n2)
61 return (object) n1 != (object) n2.name;
64 public bool Equals (Symbol name)
66 return Object.ReferenceEquals (this.name, name.name);
69 public override bool Equals (object obj)
71 return 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 Symbol Nexpr = "expr";
86 private static Symbol Nfuncall = "funcall";
87 private static Symbol Nvarref = "varref";
88 private static Symbol Ninteger = "integer";
89 private static Symbol Nstring = "string";
90 private static Symbol Nsymbol = "symbol";
91 private static Symbol Nlist = "list";
93 private static Symbol Ndefun = "defun";
94 private static Symbol Nfname = "fname";
95 private static Symbol Nargs = "args";
96 private static Symbol Nargs_unevalled = "args-unevalled";
97 private static Symbol Nfixed = "fixed";
98 private static Symbol Noptional = "optional";
99 private static Symbol Nrest = "rest";
101 private static Symbol Ndefvar = "defvar";
102 private static Symbol Nvname = "vname";
103 private static Symbol Ndescription = "description";
104 private static Symbol Nrange = "range";
106 public abstract class Function
109 public int min_arg, max_arg;
111 public Function () { }
113 public Function (Symbol name, int min_arg, int max_arg)
116 this.min_arg = min_arg;
117 this.max_arg = max_arg;
120 public abstract Term Call (Domain domain, Variable vari, Term[] args);
122 public override string ToString ()
127 internal class Subroutine : Function
129 public Builtin builtin;
132 public Subroutine (Builtin builtin, Symbol name, bool setvar,
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, Variable vari, Term[] args)
141 args = (Term[]) args.Clone ();
142 for (int i = 0; i < args.Length; i++)
144 args[i] = args[i].Eval (domain);
148 return builtin (domain, vari, args);
152 internal class SpecialForm : Function
154 public Builtin builtin;
156 public SpecialForm (Builtin builtin, Symbol name,
157 int min_arg, int max_arg)
158 : base (name, min_arg, max_arg)
160 this.builtin = builtin;
163 public override Term Call (Domain domain, Variable vari, Term[] args)
165 return builtin (domain, vari, args);
169 internal class Lambda : Function
171 internal bool args_evalled;
172 internal Variable[] args;
173 internal Term[] body;
175 public Lambda (Domain domain, XmlNode node)
180 name = node.Attributes[Nfname].Value;
182 node = node.FirstChild;
184 && (node.Name == Nargs || node.Name == Nargs_unevalled))
187 args_evalled = node.Name == Nargs;
188 for (n = node.FirstChild; n != null; n = n.NextSibling)
190 if (n.Name == Nfixed)
192 else if (n.Name == Noptional)
194 else if (n.Name == Nrest)
197 throw new Exception ("Invalid argument type: " + n);
200 max_arg = nfixed + noptional + nrest;
201 args = new Variable[max_arg];
203 for (int i = 0; i < max_arg; n = n.NextSibling)
204 args[i++] = domain.Defvar ((Symbol) n.Attributes[0].Value);
210 min_arg = max_arg = 0;
214 public Lambda (Domain domain, Symbol name, bool args_evalled, Symbol[] args)
221 this.args_evalled = args_evalled;
225 for (i = 0; i < args.Length; i++, nfixed++)
226 if (args[i] == Noptional || args[i] == Nrest)
230 if (args[i] == Noptional)
232 for (i++; i < args.Length; i++, noptional++)
233 if (args[i] == Nrest)
240 max_arg = nfixed + noptional + nrest;
241 this.args = new Variable[max_arg];
243 for (i = j = 0; j < this.args.Length; i++)
244 if (args[i] != Noptional || args[i] != Nrest)
245 this.args[j++] = domain.Defvar (args[i]);
249 min_arg = max_arg = 0;
253 public void SetBody (Domain domain, XmlNode node)
255 for (node = node.FirstChild; node != null; node = node.NextSibling)
256 if (node.Name != Ndescription
257 && node.Name != Nargs
258 && node.Name != Nargs_unevalled)
261 for (XmlNode n = node; n != null; n = n.NextSibling)
265 body = new Term[nterms];
266 for (nterms = 0; node != null; node = node.NextSibling, nterms++)
267 body[nterms] = new Term (node, domain);
271 public void SetBody (Term[] body)
276 public override Term Call (Domain domain, Variable vari, Term[] args)
278 Bindings current = domain.bindings;
285 Term[] newargs = new Term[args.Length];
286 for (i = 0; i < min_arg; i++)
287 newargs[i] = args[i].Eval (domain);
290 for (i = 0; i < min_arg; i++)
291 domain.Bind (this.args[i], args[i]);
296 domain.Catch (CatchTag.Return);
297 foreach (Term term in body)
299 result = term.Eval (domain);
309 domain.UnboundTo (current);
316 public class Variable : TermValue
318 public readonly Symbol name;
320 internal Term default_val;
324 public Variable (Symbol name, Term value)
331 public virtual bool ValueP (Term val) { return true; }
333 public override TermValue Clone ()
335 Variable v = new Variable (name, val);
337 v.default_val = default_val;
346 if (! ValueP (value))
347 throw new Exception ("Invalid value: " + value);
352 public Term DefaultValue
354 get { return default_val; }
356 if (! ValueP (value))
357 throw new Exception ("Invalid value: " + value);
362 public virtual object Range
364 get { return range; }
365 set { range = value; }
368 public override Term Eval (Domain domain) { return val; }
370 public override string ToString () { return name + "(" + val + ")"; }
372 public class Int : Variable
376 private static bool SubsetP (int[] r1, int[] r2)
380 for (int i = 0; i < r1.Length; i += 2)
383 for (j = 0; j < r2.Length; j += 2)
384 if (r2[j] <= r1[i] && r2[j + 1] >= r1[i + 1])
392 private static bool SubsetP (int val, int[] r)
396 for (int i = 0; i < r.Length; i += 2)
397 if (r[i] <= val && r[i + 1] >= val)
402 public Int (Symbol name, string description, int value, int[] range)
403 : base (name, new Term (value))
405 if (! SubsetP (value, range))
406 throw new Exception ("Invalid value: " + value);
412 public override bool ValueP (Term term)
416 return SubsetP (term.Intval, range);
419 public override object Range {
420 get { return range; }
422 int[] r = (int[]) value;
423 if (! SubsetP (r, range)
424 || ! SubsetP (val.Intval, r)
425 || ! SubsetP (default_val.Intval, r))
426 throw new Exception ("Invalid range");
432 public class Str : Variable
434 public string[] range;
436 private static bool SubsetP (string[] r1, string[] r2)
438 foreach (string s in r1)
439 if (! SubsetP (s, r2))
444 private static bool SubsetP (string str, string[] r)
446 foreach (string s in r)
452 public Str (Symbol name, string description, string value, string[] range)
453 : base (name, new Term (value))
455 if (! SubsetP (value, range))
456 throw new Exception ("Invalid value: " + value);
462 public override bool ValueP (Term term)
464 if (! (term.objval is string))
466 return SubsetP (term.Strval, range);
469 public override object Range {
470 get { return range; }
472 string[] r = (string[]) value;
473 if (! SubsetP (r, range)
474 || ! SubsetP (val.Strval, r)
475 || ! SubsetP (default_val.Strval, r))
476 throw new Exception ("Invalid range");
482 public class Sym : Variable
484 public Symbol[] range;
486 private static bool SubsetP (Symbol[] r1, Symbol[] r2)
488 foreach (Symbol n in r1)
489 if (! SubsetP (n, r2))
494 private static bool SubsetP (Symbol name, Symbol[] r)
496 foreach (Symbol n in r)
502 public Sym (Symbol name, string description, Symbol value, Symbol[] range)
503 : base (name, new Term (value))
505 if (! SubsetP (value, range))
506 throw new Exception ("Invalid value: " + value);
512 public override bool ValueP (Term term)
514 if (! (term.objval is Symbol))
516 return SubsetP (term.Symval, range);
519 public override object Range {
520 get { return range; }
522 Symbol[] r = (Symbol[]) value;
523 if (! SubsetP (r, range)
524 || ! SubsetP (val.Symval, r)
525 || ! SubsetP (default_val.Symval, r))
526 throw new Exception ("Invalid range");
533 internal class Bindings
535 private Variable vari;
536 private Term old_value;
537 private Bindings next;
539 private Bindings (Variable vari)
542 old_value = vari.val;
545 public static Bindings Bind (Bindings bindings, Variable vari, Term val)
547 Bindings b = new Bindings (vari);
554 internal Bindings UnboundTo (Bindings boundary)
556 for (Bindings b = this; b != boundary; b = b.next)
557 b.vari.val = b.old_value;
561 public override string ToString ()
563 string str = "(bindings";
564 for (Bindings b = this; b != null; b = b.next)
565 str += " " + vari.name + "=" + b.old_value;
571 internal class ThrowException : Exception
576 public ThrowException (Symbol tag, object value) : base ()
584 internal class CatchTag : IEquatable<CatchTag>
588 public CatchTag (Symbol name) { val = name.name; }
589 private CatchTag (int i) { val = i; }
591 public static CatchTag Return = new CatchTag (0);
592 public static CatchTag Break = new CatchTag (1);
594 public static bool operator== (CatchTag t1, CatchTag t2)
595 { return t1.val == t2.val; }
597 public static bool operator!= (CatchTag t1, CatchTag t2)
598 { return t1.val != t2.val; }
600 public bool Equals (CatchTag tag) { return this.val == tag.val; }
601 public override bool Equals (object val) { return this.val == val; }
603 public override int GetHashCode () { return val.GetHashCode (); }
608 public object context;
609 public int depth = 0;
611 internal Dictionary<Symbol, Function> functions
612 = new Dictionary<Symbol, Function> ();
613 internal Dictionary<Symbol, Variable> variables
614 = new Dictionary<Symbol, Variable> ();
615 internal Bindings bindings;
616 private Stack<CatchTag> catch_stack = new Stack<CatchTag> ();
617 private int catch_count = 0;
619 internal Domain () { }
621 public Domain (object context) : this (basic, context) { }
623 public Domain (Domain parent, object context)
625 functions = new Dictionary<Symbol, Function> (parent.functions);
626 variables = new Dictionary<Symbol, Variable> (parent.variables);
627 this.context = context;
630 internal void Bind (Variable vari, Term value)
632 bindings = Bindings.Bind (bindings, vari, value);
635 internal void UnboundTo (Bindings boundary)
637 if (bindings != null)
638 bindings = bindings.UnboundTo (boundary);
641 internal void Catch (CatchTag tag)
643 catch_stack.Push (tag);
647 internal void Uncatch ()
650 if (catch_count > catch_stack.Count)
655 get { return catch_count < catch_stack.Count; }
658 internal void ThrowReturn ()
660 foreach (CatchTag tag in catch_stack)
663 if (tag == CatchTag.Return)
668 internal void ThrowBreak ()
670 if (catch_stack.Peek () != CatchTag.Break)
671 throw new Exception ("No outer loop to break");
675 internal void ThrowTag (CatchTag tag)
677 foreach (CatchTag elt in catch_stack)
685 public void DefSubr (Builtin builtin, string str, bool setvar,
686 int min_arg, int max_arg, params string[] aliases)
689 Function func = new Function.Subroutine (builtin, name, setvar,
691 functions[name] = func;
692 foreach (string a in aliases)
693 functions[(Symbol) a] = func;
696 public void DefSpecial (Builtin builtin, string str,
697 int min_arg, int max_arg,
698 params string[] aliases)
701 Function func = new Function.SpecialForm (builtin, name,
703 functions[name] = func;
704 foreach (string a in aliases)
705 functions[(Symbol) a] = func;
708 public void DefAlias (string alias, string str)
710 functions[(Symbol) alias] = functions[(Symbol) str];
713 public void Defun (Symbol name, bool args_evalled,
714 Symbol[] args, Term[] body, bool prototype)
718 if (prototype || ! functions.TryGetValue (name, out func))
720 func = new Function.Lambda (this, name, args_evalled, args);
721 functions[name] = func;
724 ((Function.Lambda) func).SetBody (body);
727 public void Defun (XmlNode node, bool prototype)
729 Symbol name = node.Attributes[Nfname].Value;
732 if (prototype || ! functions.TryGetValue (name, out func))
734 func = new Function.Lambda (this, node);
735 functions[name] = func;
738 ((Function.Lambda) func).SetBody (this, node);
741 public void Defun (Function func)
743 functions[func.name] = func;
746 public Variable Defvar (XmlNode node)
748 Symbol name = node.Attributes[0].Value;
752 node = node.FirstChild;
753 if (node.Name == Ndescription)
755 desc = node.InnerText;
756 node = node.NextSibling;
762 Symbol type = node.Name;
763 XmlNodeList range_list = null;
765 string val = node.InnerText;
767 node = node.NextSibling;
770 range_list = node.ChildNodes;
771 nranges = range_list.Count;
774 if (type == Ninteger)
776 int intval = parse_integer (val);
778 if (range_list != null)
780 range = new int[nranges * 2];
781 for (int i = 0; i < nranges; i++)
783 XmlNode n = range_list[i];
784 if (n.Name == Nrange)
787 = parse_integer (n.FirstChild.InnerText);
789 = parse_integer (n.LastChild.InnerText);
795 = parse_integer (n.InnerText);
800 if (variables.TryGetValue (name, out vari))
802 if (! (vari is Variable.Int))
803 throw new Exception ("Inalid value");
804 vari = (Variable) vari.Clone ();
805 Term v = new Term (intval);
807 vari.DefaultValue = v;
812 vari = new Variable.Int (name, desc, intval, range);
814 else if (type == Nstring)
816 string[] range = null;
817 if (range_list != null)
819 range = new string[nranges];
820 for (int i = 0; i < nranges; i++)
821 range[i] = range_list[i].InnerText;
824 if (variables.TryGetValue (name, out vari))
826 if (! (vari is Variable.Str))
827 throw new Exception ("Invalid value");
828 vari = (Variable) vari.Clone ();
829 Term v = new Term (val);
831 vari.DefaultValue = v;
836 vari = new Variable.Str (name, desc, val, range);
838 else if (type == Nsymbol)
840 Symbol[] range = null;
841 if (range_list != null)
843 range = new Symbol[nranges];
844 for (int i = 0; i < nranges; i++)
845 range[i] = range_list[i].InnerText;
848 if (variables.TryGetValue (name, out vari))
850 if (! (vari is Variable.Sym))
851 throw new Exception ("Invalid value");
852 vari = (Variable) vari.Clone ();
853 Term v = new Term (val);
855 vari.DefaultValue = v;
860 vari = new Variable.Sym (name, desc, val, range);
863 throw new Exception ("Unknown type: " + type);
867 if (variables.TryGetValue (name, out vari))
868 vari = (Variable) vari.Clone ();
870 vari = new Variable (name, Zero);
872 variables[name] = vari;
876 public Variable Defvar (Variable vari)
878 variables[vari.name] = vari;
882 internal Variable Defvar (Symbol name)
884 Variable vari = new Variable (name, Zero);
885 variables[name] = vari;
889 internal Function GetFunc (Symbol name)
893 if (! functions.TryGetValue (name, out func))
894 throw new Exception ("Unknown function: " + name);
898 public bool CopyFunc (Domain domain, Symbol name)
900 Function func = GetFunc (name);
902 domain.functions[name] = func;
906 public void CopyFunc (Domain domain)
908 foreach (KeyValuePair<Symbol, Function> kv in functions)
909 domain.functions[kv.Key] = kv.Value;
912 public Variable GetVar (Symbol name, bool create)
916 if (! variables.TryGetValue (name, out vari))
920 variables[name] = vari = new Variable (name, Zero);
925 public override string ToString ()
927 string str = "<(functions";
928 foreach (KeyValuePair<Symbol, Function> kv in functions)
930 str += ") (variabls";
931 foreach (KeyValuePair<Symbol, Variable> kv in variables)
934 if (bindings != null)
935 str += " " + bindings;
937 str += " (" + context + ")";
942 internal void DebugWrite (bool head, string fmt, params string[] arg)
944 if (debug_level > depth)
948 Console.WriteLine ();
949 for (int i = 0; i < depth; i++)
952 Console.Write (fmt, arg);
956 public object SaveValues ()
958 Dictionary<Variable,Term> values = new Dictionary<Variable,Term> ();
960 foreach (KeyValuePair<Symbol,Variable> kv in variables)
961 values[kv.Value] = kv.Value.val.Clone ();
965 public void RestoreValues (object values)
967 foreach (KeyValuePair<Variable,Term> kv
968 in (Dictionary<Variable,Term>) values)
969 kv.Key.val = kv.Value;
973 public delegate Term Builtin (Domain domain, Variable vari, Term[] args);
975 private static Domain basic = new Domain ();
977 static Xexpression ()
979 basic.DefSubr (Fset, "set", true, 1, 1, "=");
980 basic.DefSubr (Fnot, "not", false, 1, 1, "!");
981 basic.DefSubr (Fadd, "add", true, 1, -1, "+");
982 basic.DefSubr (Fmul, "mul", true, 1, -1, "*");
983 basic.DefSubr (Fsub, "sub", true, 1, -1, "-");
984 basic.DefSubr (Fdiv, "div", true, 1, -1, "/");
985 basic.DefSubr (Fmod, "mod", true, 1, 2, "%");
986 basic.DefSubr (Flogior, "logior", true, 1, -1, "|");
987 basic.DefSubr (Flogand, "logand", true, 1, -1, "&");
988 basic.DefSubr (Flsh, "lsh", true, 1, 2, "<<");
989 basic.DefSubr (Frsh, "rsh", true, 1, 2, ">>");
990 basic.DefSubr (Feq, "eq", false, 2, -1, "==");
991 basic.DefSubr (Fnoteq, "noteq", false, 2, 2, "!=");
992 basic.DefSubr (Flt, "lt", false, 2, -1, "<");
993 basic.DefSubr (Fle, "le", false, 2, -1, "<=");
994 basic.DefSubr (Fgt, "gt", false, 2, -1, ">");
995 basic.DefSubr (Fge, "ge", false, 2, -1, ">=");
996 basic.DefSubr (Fappend, "append", true, 0, -1);
997 basic.DefSubr (Fconcat, "concat", true, 0, -1);
998 basic.DefSubr (Fnth, "nth", false, 2, 2);
999 basic.DefSubr (Fcopy, "copy", false, 1, 1);
1000 basic.DefSubr (Fins, "ins", true, 2, 2);
1001 basic.DefSubr (Fdel, "del", true, 2, 2);
1002 basic.DefSubr (Feval, "eval", false, 1, 1);
1003 basic.DefSubr (Fbreak, "break", false, 0, 1);
1004 basic.DefSubr (Freturn, "return", false, 0, 1);
1005 basic.DefSpecial (Fand, "and", 1, -1, "&&");
1006 basic.DefSpecial (For, "or", 1, -1, "||");
1007 basic.DefSpecial (Fprogn, "progn", 0, -1, "expr");
1008 basic.DefSpecial (Fif, "if", 2, 3);
1009 basic.DefSpecial (Fwhen, "when", 1, -1);
1010 basic.DefSpecial (Floop, "loop", 1, -1);
1011 basic.DefSpecial (Fwhile, "while", 1, -1);
1012 basic.DefSpecial (Fcond, "cond", 1, -1);
1013 basic.DefSpecial (Fforeach, "foreach", 2, -1);
1014 basic.DefSpecial (Fquote, "quote", 1, 1);
1015 basic.DefSpecial (Ftype, "type", 1, 1);
1016 basic.DefSpecial (Fcatch, "catch", 2, 2);
1017 basic.DefSpecial (Fthrow, "throw", 1, 2);
1020 private static Term Fset (Domain domain, Variable vari, Term[] args)
1022 vari.Value = args[0];
1026 private static Term Fnot (Domain domain, Variable vari, Term[] args)
1028 return args[0].IsTrue ? Zero : One;
1031 private static Term Fadd (Domain domain, Variable vari, Term[] args)
1033 int n = vari == null ? 0 : vari.val.Intval;
1035 foreach (Term arg in args)
1038 return new Term (n);
1039 vari.val.intval = n;
1043 private static Term Fmul (Domain domain, Variable vari, Term[] args)
1045 int n = vari == null ? 1 : vari.val.Intval;
1046 foreach (Term arg in args)
1049 return new Term (n);
1050 vari.val.intval = n;
1054 private static Term Fsub (Domain domain, Variable vari, Term[] args)
1065 n = vari.val.Intval;
1068 while (i < args.Length)
1069 n -= args[i++].Intval;
1071 return new Term (n);
1072 vari.val.intval = n;
1076 private static Term Fdiv (Domain domain, Variable vari, Term[] args)
1087 n = vari.val.Intval;
1090 while (i < args.Length)
1091 n /= args[i++].Intval;
1093 return new Term (n);
1094 vari.val.intval = n;
1098 private static Term Fmod (Domain domain, Variable vari, Term[] args)
1101 return new Term (args[0].Intval % args[1].Intval);
1102 vari.val.intval = vari.val.Intval % args[0].Intval;
1106 private static Term Flogior (Domain domain, Variable vari, Term[] args)
1108 int n = vari == null ? 0 : vari.val.Intval;
1109 foreach (Term arg in args)
1112 return new Term (n);
1113 vari.val.intval = n;
1117 private static Term Flogand (Domain domain, Variable vari, Term[] args)
1128 n = vari.val.Intval;
1131 while (i < args.Length)
1132 n &= args[i++].Intval;
1134 return new Term (n);
1135 vari.val.intval = n;
1139 private static Term Flsh (Domain domain, Variable vari, Term[] args)
1142 return new Term (args[0].Intval << args[1].Intval);
1143 vari.val.intval = vari.val.Intval << args[0].Intval;
1147 private static Term Frsh (Domain domain, Variable vari, Term[] args)
1150 return new Term (args[0].Intval >> args[1].Intval);
1151 vari.val.intval = vari.val.Intval >> args[0].Intval;
1155 private static Term Feq (Domain domain, Variable vari, Term[] args)
1159 if (o.objval == null)
1161 for (int i = 1; i < args.Length; i++)
1162 if (args[i].objval != null || args[i].intval != o.intval)
1167 for (int i = 1; i < args.Length; i++)
1168 if (o.objval.Equals (args[i].objval))
1174 private static Term Fnoteq (Domain domain, Variable vari, Term[] args)
1176 return Feq (domain, vari, args);
1179 private static Term Flt (Domain domain, Variable vari, Term[] args)
1181 int n = args[0].Intval;
1183 for (int i = 1; i < args.Length; i++)
1185 int n1 = args[i].Intval;
1193 private static Term Fle (Domain domain, Variable vari, Term[] args)
1195 int n = args[0].Intval;
1196 for (int i = 1; i < args.Length; i++)
1198 int n1 = args[i].Intval;
1206 private static Term Fgt (Domain domain, Variable vari, Term[] args)
1208 int n = args[0].Intval;
1209 for (int i = 1; i < args.Length; i++)
1211 int n1 = args[i].Intval;
1219 private static Term Fge (Domain domain, Variable vari, Term[] args)
1221 int n = args[0].Intval;
1222 for (int i = 1; i < args.Length; i++)
1224 int n1 = args[i].Intval;
1232 private static Term Fappend (Domain domain, Variable vari, Term[] args)
1237 list = new List<Term> ();
1239 list = vari.val.Listval;
1241 foreach (Term arg in args)
1244 list.AddRange ((List<Term>) arg.objval);
1252 result.objval = list;
1258 private static Term Fconcat (Domain domain, Variable vari, Term[] args)
1265 str = vari.val.Strval;
1267 foreach (Term arg in args)
1270 str += (string) arg.objval;
1271 else if (arg.IsList)
1272 foreach (Term term in (List<Term>) arg.objval)
1273 str += (char) term.Intval;
1275 str += (char) arg.Intval;
1281 result.objval = str;
1284 vari.val.objval = str;
1288 private static Term Fnth (Domain domain, Variable vari, Term[] args)
1294 result.intval = ((string) args[1].objval)[args[0].Intval];
1295 result.objval = null;
1297 else if (args[1].IsList)
1299 result = ((List<Term>) args[1].objval)[args[0].Intval];
1302 throw new Exception ("Term is not enumelable: " + args[1]);
1306 private static Term Fcopy (Domain domain, Variable vari, Term[] args)
1311 result.objval = new List<Term> (args[0].Listval);
1315 private static Term Fins (Domain domain, Variable vari, Term[] args)
1319 = vari.val.Strval.Insert (args[0].Intval, args[1].Strval);
1320 else if (vari.val.IsList)
1321 vari.val.Listval.InsertRange (args[0].Intval, args[1].Listval);
1323 throw new Exception ("term is not collection: " + vari.val);
1327 private static Term Fdel (Domain domain, Variable vari, Term[] args)
1331 = vari.val.Strval.Remove (args[0].Intval,
1332 args[1].Intval - args[0].Intval);
1334 else if (vari.val.IsList)
1335 vari.val.Listval.RemoveRange (args[0].Intval,
1336 args[1].Intval - args[0].Intval);
1338 throw new Exception ("term is not collection: " + vari.val);
1342 private static Term Fand (Domain domain, Variable vari, Term[] args)
1344 foreach (Term arg in args)
1345 if (! arg.Eval (domain).IsTrue)
1350 private static Term For (Domain domain, Variable vari, Term[] args)
1352 foreach (Term arg in args)
1353 if (arg.Eval (domain).IsTrue)
1358 private static Term Feval (Domain domain, Variable vari, Term[] args)
1360 return (args[0].Eval (domain));
1363 private static Term Fprogn (Domain domain, Variable vari, Term[] args)
1367 foreach (Term arg in args)
1368 result = arg.Eval (domain);
1372 private static Term Fif (Domain domain, Variable vari, Term[] args)
1374 if (args[0].Eval (domain).IsTrue)
1375 return args[1].Eval (domain);
1376 if (args.Length == 2)
1378 return args[2].Eval (domain);
1381 private static Term Fwhen (Domain domain, Variable vari, Term[] args)
1383 if (! args[0].Eval (domain).IsTrue)
1386 for (int i = 1; i < args.Length; i++)
1387 result = args[i].Eval (domain);
1391 private static Term Freturn (Domain domain, Variable vari, Term[] args)
1393 domain.ThrowReturn ();
1394 return args.Length == 0 ? Zero : args[0];
1397 private static Term Fbreak (Domain domain, Variable vari, Term[] args)
1399 domain.ThrowBreak ();
1400 return args.Length == 0 ? Zero : args[0];
1403 private static Term Floop (Domain domain, Variable vari, Term[] args)
1407 domain.Catch (CatchTag.Break);
1408 while (! domain.Thrown)
1409 foreach (Term arg in args)
1411 result = arg.Eval (domain);
1421 private static Term Fwhile (Domain domain, Variable vari, Term[] args)
1425 domain.Catch (CatchTag.Break);
1426 while (! domain.Thrown && args[0].Eval (domain).IsTrue)
1427 for (int i = 1; i < args.Length; i++)
1429 result = args[i].Eval (domain);
1439 private static Term Fcond (Domain domain, Variable vari, Term[] args)
1441 foreach (Term arg in args)
1443 List<Term> list = arg.Listval;
1444 Term result = list[0].Eval (domain);
1448 for (int i = 1; i < list.Count; i++)
1449 result = list[i].Eval (domain);
1456 private static Term Fforeach (Domain domain, Variable vari,
1459 Term result = args[0].Eval (domain);
1462 List<Term> list = result.Listval;
1463 Bindings current = domain.bindings;
1466 domain.Catch (CatchTag.Break);
1467 foreach (Term term in list)
1469 domain.Bind (vari, term);
1471 for (int i = 1; i < args.Length; i++)
1473 result = args[i].Eval (domain);
1478 domain.UnboundTo (current);
1487 private static Term Fquote (Domain domain, Variable vari, Term[] args)
1489 return new Term (args[0]);
1492 private static Term Ftype (Domain domain, Variable vari, Term[] args)
1498 if (args[0].IsSymbol)
1505 public static Term Fcatch (Domain domain, Variable vari, Term[] args)
1509 domain.Catch (new CatchTag (args[0].Symval));
1510 result = args[1].Eval (domain);
1517 public static Term Fthrow (Domain domain, Variable vari, Term[] args)
1519 domain.ThrowTag (new CatchTag (args[0].Symval));
1520 return (args.Length == 1 ? Zero : args[1]);
1523 public abstract class TermValue
1525 public virtual Term Eval (Domain domain) { return new Term (this); }
1526 public abstract TermValue Clone ();
1529 private class Funcall : TermValue
1531 internal Function func;
1532 internal Variable vari;
1533 internal Term[] args;
1535 private Funcall (Function func, Variable vari, Term[] args)
1542 public Funcall (XmlNode node, Domain domain)
1545 Symbol name = node.Name;
1547 if (name == Nfuncall)
1548 name = node.Attributes[0].Value;
1549 else if (node.Attributes[Nvname] != null)
1550 vari = domain.GetVar (node.Attributes[Nvname].Value, true);
1551 func = domain.GetFunc (name);
1552 XmlNodeList nlist = node.ChildNodes;
1553 int nargs = nlist.Count;
1555 if (nargs < func.min_arg
1556 || (func.max_arg >= 0 && nargs > func.max_arg))
1557 throw new Exception ("Invalid number of arguments to: "
1558 + name + " " + nargs);
1559 args = new Term[nargs];
1560 for (int i = 0; i < nlist.Count; i++)
1561 args[i] = new Term (nlist[i], domain);
1564 public Funcall (Domain domain, Symbol fname, Term[] args)
1566 func = domain.GetFunc (fname);
1570 public Funcall (Domain domain, Symbol fname, Symbol vname, Term[] args)
1572 func = domain.GetFunc (fname);
1573 vari = domain.GetVar (vname, true);
1577 public override Term Eval (Domain domain)
1579 domain.DebugWrite (true, "(({0}", func.name);
1580 for (int i = 0; i < args.Length; i++)
1581 domain.DebugWrite (false, " {0}", args[i].ToString ());
1582 domain.DebugWrite (false, ")");
1584 Term result = func.Call (domain, vari, args);
1586 domain.DebugWrite (true, " ==> {0})", result.ToString ());
1590 public override TermValue Clone ()
1592 return new Funcall (func, vari, args);
1595 public override string ToString ()
1597 string str = "<funcall fname=\"" + func.name;
1599 return str + "\"/>";
1601 foreach (Term e in args)
1603 return (str + "</funcall>");
1610 public object objval;
1612 public Term (int i) { intval = i; objval = null; }
1613 public Term (Symbol name) { intval = 0; objval = name; }
1614 public Term (string str) { intval = 0; objval = str; }
1615 public Term (List<Term> list) { intval = 0; objval = list; }
1616 public Term (Term term) { intval = term.intval; objval = term.objval; }
1617 public Term (TermValue obj) { intval = 0; objval = obj; }
1619 public Term (XmlNode node, Domain domain)
1621 Symbol name = node.Name;
1623 if (name == Ninteger)
1625 intval = parse_integer (node.InnerText);
1631 if (name == Nsymbol)
1632 objval = (Symbol) node.InnerText;
1633 else if (name == Nstring)
1634 objval = node.InnerText.Clone ();
1635 else if (name == Nvarref)
1636 objval = domain.GetVar ((Symbol) node.Attributes[0].Value, true);
1637 else if (name == Nlist)
1639 List<Term> list = new List<Term> ();
1640 for (node = node.FirstChild; node != null;
1641 node = node.NextSibling)
1642 list.Add (new Term (node, domain));
1646 objval = new Funcall (node, domain);
1650 public Term (Domain domain, Symbol fname, Term[] args)
1653 objval = new Funcall (domain, fname, args);
1656 public Term (Domain domain, Symbol fname, Symbol vname, Term[] args)
1659 objval = new Funcall (domain, fname, vname, args);
1662 public object Objval {
1665 throw new Exception ("term is an integer: " + this);
1673 throw new Exception ("term is not integer: " + this);
1678 public string Strval {
1681 throw new Exception ("term is not string: " + this);
1682 return (string) objval;
1686 public string Symval {
1689 throw new Exception ("term is not symbol: " + this);
1690 return (Symbol) objval;
1694 public List<Term> Listval {
1697 throw new Exception ("term is not list: " + this);
1698 return (List<Term>) objval;
1702 public bool IsTrue {
1704 return (objval == null
1706 : objval is List<Term>
1707 ? (((List<Term>) objval).Count != 0)
1711 public bool IsInt { get { return (objval == null); } }
1712 public bool IsStr { get { return (objval is string); } }
1713 public bool IsSymbol { get { return (objval is Symbol); } }
1714 public bool IsList { get { return (objval is List<Term>); } }
1716 public bool IsType (Type type)
1718 return (objval == null ? type == typeof (int)
1719 : type == objval.GetType ());
1722 public Term Eval (Domain domain)
1724 if (objval == null || objval is Symbol || objval is string)
1726 if (objval is List<Term>)
1727 return new Term ((List<Term>) objval);
1728 return ((TermValue) objval).Eval (domain);
1731 public Term Clone ()
1733 if (objval == null || objval is Symbol || objval is string)
1735 if (objval is List<Term>)
1737 List<Term> list = new List<Term> ();
1738 list.InsertRange (0, ((List<Term>) objval));
1739 return new Term (list);
1741 return new Term (((TermValue) objval).Clone ());
1744 public override string ToString ()
1749 str = "<integer>" + intval + "</integer>";
1750 else if (objval is Symbol)
1751 str = "<symbol>" + objval + "</symbol>";
1752 else if (objval is string)
1753 str = "<string>" + objval + "</string>";
1754 else if (objval is List<Term>)
1757 foreach (Term e in (List<Term>) objval)
1761 else if (objval is Funcall)
1762 str = "<funcall fname=\"" + ((Funcall) objval).func.name + "\"/>";
1763 else if (objval is Variable)
1764 str = "<variable vname=\"" + ((Variable) objval).name + "\"/>";
1765 else if (objval is Term)
1766 str = "<quote>" + objval + "</quote>";
1768 throw new Exception ("invalid Term object: " + objval);
1773 static private Term Zero = new Term (0);
1774 static private Term One = new Term (1);
1775 static private Term TermInt = new Term (Ninteger);
1776 static private Term TermStr = new Term (Nstring);
1777 static private Term TermSymbol = new Term (Nsymbol);
1778 static private Term TermList = new Term (Nlist);
1779 static private Term TermTerm = new Term ((Symbol) "term");
1781 internal static int parse_integer (string str)
1783 int len = str.Length;
1784 bool negative = false;
1787 return (len == 0 ? 0 : str[0] - '0');
1794 if ((c == '0' || c == '#') && str[1] == 'x')
1797 for (int idx = 2; idx < len; idx++)
1803 i = i * 16 + (c - '0');
1807 i = i * 16 + (c - 'A');
1811 i = i * 16 + (c - 'a');
1820 for (int idx = 1; idx < len; idx++)
1823 if (c < '0' || c > '9')
1825 i = i * 10 + (c - '0');
1827 return negative ? - i : i;
1830 private Term[] terms;
1832 private void parse_terms (Domain domain, XmlNode node)
1835 for (XmlNode n = node; n != null; n = n.NextSibling)
1836 if (n.NodeType == XmlNodeType.Element)
1838 if (n.Name == Ndefun)
1839 domain.Defun (n, true);
1840 else if (n.Name == Ndefvar)
1846 terms = new Term[nterms];
1848 for (XmlNode n = node; n != null; n = n.NextSibling)
1849 if (n.NodeType == XmlNodeType.Element)
1851 if (n.Name == Ndefun)
1852 domain.Defun (n, false);
1853 else if (n.Name != Ndefvar)
1854 terms[i++]= new Term (n, domain);
1858 public Xexpression (Domain domain, XmlNode node)
1860 parse_terms (domain, node);
1863 public Xexpression (Domain domain, string url)
1865 XmlDocument doc = new XmlDocument (Symbol.Table);
1868 using (XmlTextReader reader = new XmlTextReader (url, Symbol.Table))
1872 } while (reader.NodeType != XmlNodeType.None
1873 && (reader.NodeType != XmlNodeType.Element
1874 || reader.Name != Nexpr));
1875 if (reader.NodeType == XmlNodeType.None)
1876 throw new Exception ("Node <expr> not found");
1877 node = doc.ReadNode (reader);
1879 parse_terms (domain, node.FirstChild);
1882 public Term Eval (Domain domain)
1888 domain.Catch (CatchTag.Return);
1889 foreach (Term term in terms)
1891 result = term.Eval (domain);
1901 public override string ToString ()
1904 for (int i = 0; i < terms.Length; i++)