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 internal abstract class Function
109 public int min_arg, max_arg;
111 public Function () { }
113 public Function (Name 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, Name 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, Name 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 (XmlNode node, Domain domain)
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 ((Name) n.Attributes[0].Value);
210 min_arg = max_arg = 0;
214 public void SetBody (XmlNode node, Domain domain)
216 for (node = node.FirstChild; node != null; node = node.NextSibling)
217 if (node.Name != Ndescription
218 && node.Name != Nargs
219 && node.Name != Nargs_unevalled)
222 for (XmlNode n = node; n != null; n = n.NextSibling)
226 body = new Term[nterms];
227 for (nterms = 0; node != null; node = node.NextSibling, nterms++)
228 body[nterms] = new Term (node, domain);
232 public override Term Call (Domain domain, Variable vari, Term[] args)
234 Bindings current = domain.bindings;
241 Term[] newargs = new Term[args.Length];
242 for (i = 0; i < min_arg; i++)
243 newargs[i] = args[i].Eval (domain);
246 for (i = 0; i < min_arg; i++)
247 domain.Bind (this.args[i], args[i]);
252 domain.Catch (CatchTag.Return);
253 foreach (Term term in body)
255 result = term.Eval (domain);
265 domain.UnboundTo (current);
272 public class Variable : TermValue
274 public readonly Name name;
276 internal Term default_val;
280 public Variable (Name name, Term value)
287 public virtual bool ValueP (Term val) { return true; }
289 public Variable Clone ()
291 Variable v = new Variable (name, val);
293 v.default_val = default_val;
302 if (! ValueP (value))
303 throw new Exception ("Invalid value: " + value);
308 public Term DefaultValue
310 get { return default_val; }
312 if (! ValueP (value))
313 throw new Exception ("Invalid value: " + value);
318 public virtual object Range
320 get { return range; }
321 set { range = value; }
324 public override Term Eval (Domain domain) { return val; }
326 public override string ToString () { return name + "(" + val + ")"; }
328 public class Int : Variable
332 private static bool SubsetP (int[] r1, int[] r2)
336 for (int i = 0; i < r1.Length; i += 2)
339 for (j = 0; j < r2.Length; j += 2)
340 if (r2[j] <= r1[i] && r2[j + 1] >= r1[i + 1])
348 private static bool SubsetP (int val, int[] r)
352 for (int i = 0; i < r.Length; i += 2)
353 if (r[i] <= val && r[i + 1] >= val)
358 public Int (Name name, string description, int value, int[] range)
359 : base (name, new Term (value))
361 if (! SubsetP (value, range))
362 throw new Exception ("Invalid value: " + value);
368 public override bool ValueP (Term term)
372 return SubsetP (term.Intval, range);
375 public override object Range {
376 get { return range; }
378 int[] r = (int[]) value;
379 if (! SubsetP (r, range)
380 || ! SubsetP (val.Intval, r)
381 || ! SubsetP (default_val.Intval, r))
382 throw new Exception ("Invalid range");
388 internal class Str : Variable
390 public string[] range;
392 private static bool SubsetP (string[] r1, string[] r2)
394 foreach (string s in r1)
395 if (! SubsetP (s, r2))
400 private static bool SubsetP (string str, string[] r)
402 foreach (string s in r)
408 public Str (Name name, string description, string value, string[] range)
409 : base (name, new Term (value))
411 if (! SubsetP (value, range))
412 throw new Exception ("Invalid value: " + value);
418 public override bool ValueP (Term term)
420 if (! (term.objval is string))
422 return SubsetP (term.Strval, range);
425 public override object Range {
426 get { return range; }
428 string[] r = (string[]) value;
429 if (! SubsetP (r, range)
430 || ! SubsetP (val.Strval, r)
431 || ! SubsetP (default_val.Strval, r))
432 throw new Exception ("Invalid range");
438 internal class Sym : Variable
442 private static bool SubsetP (Name[] r1, Name[] r2)
444 foreach (Name n in r1)
445 if (! SubsetP (n, r2))
450 private static bool SubsetP (Name name, Name[] r)
452 foreach (Name n in r)
458 public Sym (Name name, string description, Name value, Name[] range)
459 : base (name, new Term (value))
461 if (! SubsetP (value, range))
462 throw new Exception ("Invalid value: " + value);
468 public override bool ValueP (Term term)
470 if (! (term.objval is Name))
472 return SubsetP (term.Nameval, range);
475 public override object Range {
476 get { return range; }
478 Name[] r = (Name[]) value;
479 if (! SubsetP (r, range)
480 || ! SubsetP (val.Nameval, r)
481 || ! SubsetP (default_val.Nameval, r))
482 throw new Exception ("Invalid range");
489 internal class Bindings
491 private Variable vari;
492 private Term old_value;
493 private Bindings next;
495 private Bindings (Variable vari)
498 old_value = vari.val;
501 public static Bindings Bind (Bindings bindings, Variable vari, Term val)
503 Bindings b = new Bindings (vari);
510 internal Bindings UnboundTo (Bindings boundary)
512 for (Bindings b = this; b != boundary; b = b.next)
513 b.vari.val = b.old_value;
517 public override string ToString ()
519 string str = "(bindings";
520 for (Bindings b = this; b != null; b = b.next)
521 str += " " + vari.name + "=" + b.old_value;
527 internal class ThrowException : Exception
532 public ThrowException (Name tag, object value) : base ()
540 internal class CatchTag : IEquatable<CatchTag>
544 public CatchTag (Name name) { val = name.name; }
545 private CatchTag (int i) { val = i; }
547 public static CatchTag Return = new CatchTag (0);
548 public static CatchTag Break = new CatchTag (1);
550 public static bool operator== (CatchTag t1, CatchTag t2)
551 { return t1.val == t2.val; }
553 public static bool operator!= (CatchTag t1, CatchTag t2)
554 { return t1.val != t2.val; }
556 public bool Equals (CatchTag tag) { return this.val == tag.val; }
557 public override bool Equals (object val) { return this.val == val; }
559 public override int GetHashCode () { return val.GetHashCode (); }
564 public object context;
565 public int depth = 0;
567 internal Dictionary<Name, Function> functions;
568 internal Dictionary<Name, Dictionary<Name, Function>>
569 modules = new Dictionary<Name, Dictionary<Name, Function>> ();
570 internal Dictionary<Name, Variable> variables;
571 internal Bindings bindings;
572 private Stack<CatchTag> catch_stack = new Stack<CatchTag> ();
573 private int catch_count = 0;
577 functions = new Dictionary<Name, Function> ();
578 variables = new Dictionary<Name, Variable> ();
581 public Domain (object context) : this (basic, context)
585 public Domain (Domain parent, object context)
587 functions = new Dictionary<Name, Function> (parent.functions);
588 variables = new Dictionary<Name, Variable> (parent.variables);
589 this.context = context;
592 internal void Bind (Variable vari, Term value)
594 bindings = Bindings.Bind (bindings, vari, value);
597 internal void UnboundTo (Bindings boundary)
599 if (bindings != null)
600 bindings = bindings.UnboundTo (boundary);
603 internal void Catch (CatchTag tag)
605 catch_stack.Push (tag);
609 internal void Uncatch ()
612 if (catch_count > catch_stack.Count)
616 internal bool Thrown {
617 get { return catch_count < catch_stack.Count; }
620 internal void ThrowReturn ()
622 foreach (CatchTag tag in catch_stack)
625 if (tag == CatchTag.Return)
630 internal void ThrowBreak ()
632 if (catch_stack.Peek () != CatchTag.Break)
633 throw new Exception ("No outer loop to break");
637 internal void ThrowTag (CatchTag tag)
639 foreach (CatchTag elt in catch_stack)
647 public void DefSubr (Builtin builtin, string str, bool setvar,
648 int min_arg, int max_arg, params string[] aliases)
651 Function func = new Function.Subroutine (builtin, name, setvar,
653 functions[name] = func;
654 foreach (string a in aliases)
655 functions[(Name) a] = func;
658 public void DefSpecial (Builtin builtin, string str,
659 int min_arg, int max_arg,
660 params string[] aliases)
663 Function func = new Function.SpecialForm (builtin, name,
665 functions[name] = func;
666 foreach (string a in aliases)
667 functions[(Name) a] = func;
670 public void DefAlias (string alias, string str)
672 functions[(Name) alias] = functions[(Name) str];
675 internal Function.Lambda RegisterFunction (XmlNode node)
677 Function.Lambda lambda = new Function.Lambda (node, this);
679 functions[lambda.name] = lambda;
683 public void Defun (XmlNode node)
685 Name name = node.Attributes[Nfname].Value;
688 if (! functions.TryGetValue (name, out func))
689 func = RegisterFunction (node);
690 ((Function.Lambda) func).SetBody (node, this);
693 public void Defvar (XmlNode node)
695 Name name = node.Attributes[0].Value;
699 node = node.FirstChild;
700 if (node.Name == Ndescription)
702 desc = node.InnerText;
703 node = node.NextSibling;
709 Name type = node.Name;
710 XmlNodeList range_list = null;
712 string val = node.InnerText;
714 node = node.NextSibling;
717 range_list = node.ChildNodes;
718 nranges = range_list.Count;
721 if (type == Ninteger)
723 int intval = parse_integer (val);
725 if (range_list != null)
727 range = new int[nranges * 2];
728 for (int i = 0; i < nranges; i++)
730 XmlNode n = range_list[i];
731 if (n.Name == Nrange)
734 = parse_integer (n.FirstChild.InnerText);
736 = parse_integer (n.LastChild.InnerText);
742 = parse_integer (n.InnerText);
747 if (variables.TryGetValue (name, out vari))
749 if (! (vari is Variable.Int))
750 throw new Exception ("Inalid value");
751 vari = vari.Clone ();
752 Term v = new Term (intval);
754 vari.DefaultValue = v;
759 vari = new Variable.Int (name, desc, intval, range);
761 else if (type == Nstring)
763 string[] range = null;
764 if (range_list != null)
766 range = new string[nranges];
767 for (int i = 0; i < nranges; i++)
768 range[i] = range_list[i].InnerText;
771 if (variables.TryGetValue (name, out vari))
773 if (! (vari is Variable.Str))
774 throw new Exception ("Invalid value");
775 vari = vari.Clone ();
776 Term v = new Term (val);
778 vari.DefaultValue = v;
783 vari = new Variable.Str (name, desc, val, range);
785 else if (type == Nsymbol)
788 if (range_list != null)
790 range = new Name[nranges];
791 for (int i = 0; i < nranges; i++)
792 range[i] = range_list[i].InnerText;
795 if (variables.TryGetValue (name, out vari))
797 if (! (vari is Variable.Sym))
798 throw new Exception ("Invalid value");
799 vari = vari.Clone ();
800 Term v = new Term (val);
802 vari.DefaultValue = v;
807 vari = new Variable.Sym (name, desc, val, range);
810 throw new Exception ("Unknown type: " + type);
814 if (variables.TryGetValue (name, out vari))
815 vari = vari.Clone ();
817 vari = new Variable (name, Zero);
819 variables[name] = vari;
822 public void Defvar (Variable vari)
824 variables[vari.name] = vari;
827 internal Variable Defvar (Name name)
829 Variable vari = new Variable (name, Zero);
830 variables[name] = vari;
834 internal Function GetFunc (Name name)
838 if (! functions.TryGetValue (name, out func))
839 throw new Exception ("Unknown function: " + name);
843 public bool CopyFunc (Domain domain, Name name)
845 Function func = GetFunc (name);
847 domain.functions[name] = func;
851 public void CopyFunc (Domain domain)
853 foreach (KeyValuePair<Name, Function> kv in functions)
854 domain.functions[kv.Key] = kv.Value;
857 public Variable GetVar (Name name)
861 if (! variables.TryGetValue (name, out vari))
862 variables[name] = vari = new Variable (name, Zero);
866 public override string ToString ()
868 string str = "<(functions";
869 foreach (KeyValuePair<Name, Function> kv in functions)
871 str += ") (variabls";
872 foreach (KeyValuePair<Name, Variable> kv in variables)
875 if (bindings != null)
876 str += " " + bindings;
878 str += " (" + context + ")";
883 internal void DebugWrite (bool head, string fmt, params string[] arg)
885 if (debug_level > depth)
889 Console.WriteLine ();
890 for (int i = 0; i < depth; i++)
893 Console.Write (fmt, arg);
898 public delegate Term Builtin (Domain domain, Variable vari, Term[] args);
900 private static Domain basic = new Domain ();
902 static Xexpression ()
904 basic.DefSubr (Fset, "set", true, 1, 1, "=");
905 basic.DefSubr (Fnot, "not", false, 1, 1, "!");
906 basic.DefSubr (Fadd, "add", true, 1, -1, "+");
907 basic.DefSubr (Fmul, "mul", true, 1, -1, "*");
908 basic.DefSubr (Fsub, "sub", true, 1, -1, "-");
909 basic.DefSubr (Fdiv, "div", true, 1, -1, "/");
910 basic.DefSubr (Fmod, "mod", true, 1, 2, "%");
911 basic.DefSubr (Flogior, "logior", true, 1, -1, "|");
912 basic.DefSubr (Flogand, "logand", true, 1, -1, "&");
913 basic.DefSubr (Flsh, "lsh", true, 1, 2, "<<");
914 basic.DefSubr (Frsh, "rsh", true, 1, 2, ">>");
915 basic.DefSubr (Feq, "eq", false, 2, -1, "==");
916 basic.DefSubr (Fnoteq, "noteq", false, 2, 2, "!=");
917 basic.DefSubr (Flt, "lt", false, 2, -1, "<");
918 basic.DefSubr (Fle, "le", false, 2, -1, "<=");
919 basic.DefSubr (Fgt, "gt", false, 2, -1, ">");
920 basic.DefSubr (Fge, "ge", false, 2, -1, ">=");
921 basic.DefSubr (Fappend, "append", true, 0, -1);
922 basic.DefSubr (Fconcat, "concat", true, 0, -1);
923 basic.DefSubr (Fnth, "nth", false, 2, 2);
924 basic.DefSubr (Fcopy, "copy", false, 1, 1);
925 basic.DefSubr (Fins, "ins", true, 2, 2);
926 basic.DefSubr (Fdel, "del", true, 2, 2);
927 basic.DefSubr (Feval, "eval", false, 1, 1);
928 basic.DefSubr (Fbreak, "break", false, 0, 1);
929 basic.DefSubr (Freturn, "return", false, 0, 1);
930 basic.DefSpecial (Fand, "and", 1, -1, "&&");
931 basic.DefSpecial (For, "or", 1, -1, "||");
932 basic.DefSpecial (Fprogn, "progn", 0, -1, "expr");
933 basic.DefSpecial (Fif, "if", 2, 3);
934 basic.DefSpecial (Fwhen, "when", 1, -1);
935 basic.DefSpecial (Floop, "loop", 1, -1);
936 basic.DefSpecial (Fwhile, "while", 1, -1);
937 basic.DefSpecial (Fcond, "cond", 1, -1);
938 basic.DefSpecial (Fforeach, "foreach", 2, -1);
939 basic.DefSpecial (Fquote, "quote", 1, 1);
940 basic.DefSpecial (Ftype, "type", 1, 1);
941 basic.DefSpecial (Fcatch, "catch", 2, 2);
942 basic.DefSpecial (Fthrow, "throw", 1, 2);
945 private static Term Fset (Domain domain, Variable vari, Term[] args)
947 vari.Value = args[0];
951 private static Term Fnot (Domain domain, Variable vari, Term[] args)
953 return args[0].IsTrue ? Zero : One;
956 private static Term Fadd (Domain domain, Variable vari, Term[] args)
958 int n = vari == null ? 0 : vari.val.Intval;
960 foreach (Term arg in args)
968 private static Term Fmul (Domain domain, Variable vari, Term[] args)
970 int n = vari == null ? 1 : vari.val.Intval;
971 foreach (Term arg in args)
979 private static Term Fsub (Domain domain, Variable vari, Term[] args)
993 while (i < args.Length)
994 n -= (int) args[i++];
1001 private static Term Fdiv (Domain domain, Variable vari, Term[] args)
1012 n = vari.val.Intval;
1015 while (i < args.Length)
1016 n /= args[i++].Intval;
1019 vari.val.intval = n;
1023 private static Term Fmod (Domain domain, Variable vari, Term[] args)
1026 return (args[0].Intval % args[1].Intval);
1027 vari.val.intval = vari.val.Intval % args[0].Intval;
1031 private static Term Flogior (Domain domain, Variable vari, Term[] args)
1033 int n = vari == null ? 0 : vari.val.Intval;
1034 foreach (Term arg in args)
1038 vari.val.intval = n;
1042 private static Term Flogand (Domain domain, Variable vari, Term[] args)
1053 n = vari.val.Intval;
1056 while (i < args.Length)
1057 n &= (int) args[i++];
1060 vari.val.intval = n;
1064 private static Term Flsh (Domain domain, Variable vari, Term[] args)
1067 return args[0].Intval << args[1].Intval;
1068 vari.val.intval = vari.val.Intval << args[0].Intval;
1072 private static Term Frsh (Domain domain, Variable vari, Term[] args)
1075 return args[0].Intval >> args[1].Intval;
1076 vari.val.intval = vari.val.Intval >> args[0].Intval;
1080 private static Term Feq (Domain domain, Variable vari, Term[] args)
1084 if (o.objval == null)
1086 for (int i = 1; i < args.Length; i++)
1087 if (args[i].objval != null || args[i].intval != o.intval)
1092 for (int i = 1; i < args.Length; i++)
1093 if (o.objval.Equals (args[i].objval))
1099 private static Term Fnoteq (Domain domain, Variable vari, Term[] args)
1101 return Feq (domain, vari, args);
1104 private static Term Flt (Domain domain, Variable vari, Term[] args)
1106 int n = (int) args[0];
1108 for (int i = 1; i < args.Length; i++)
1110 int n1 = (int) args[i];
1118 private static Term Fle (Domain domain, Variable vari, Term[] args)
1120 int n = (int) args[0];
1121 for (int i = 1; i < args.Length; i++)
1123 int n1 = (int) args[i];
1131 private static Term Fgt (Domain domain, Variable vari, Term[] args)
1133 int n = (int) args[0];
1134 for (int i = 1; i < args.Length; i++)
1136 int n1 = (int) args[i];
1144 private static Term Fge (Domain domain, Variable vari, Term[] args)
1146 int n = (int) args[0];
1147 for (int i = 1; i < args.Length; i++)
1149 int n1 = (int) args[i];
1157 private static Term Fappend (Domain domain, Variable vari, Term[] args)
1162 list = new List<Term> ();
1164 list = vari.val.Listval;
1166 foreach (Term arg in args)
1169 list.AddRange ((List<Term>) arg.objval);
1177 result.objval = list;
1183 private static Term Fconcat (Domain domain, Variable vari, Term[] args)
1190 str = vari.val.Strval;
1192 foreach (Term arg in args)
1195 str += (string) arg.objval;
1196 else if (arg.IsList)
1197 foreach (Term term in (List<Term>) arg.objval)
1198 str += (char) term.Intval;
1200 str += (char) arg.Intval;
1206 result.objval = str;
1209 vari.val.objval = str;
1213 private static Term Fnth (Domain domain, Variable vari, Term[] args)
1219 result.intval = ((string) args[1].objval)[args[0].Intval];
1220 result.objval = null;
1222 else if (args[1].IsList)
1224 result = ((List<Term>) args[1].objval)[args[0].Intval];
1227 throw new Exception ("Term is not enumelable: " + args[1]);
1231 private static Term Fcopy (Domain domain, Variable vari, Term[] args)
1236 result.objval = new List<Term> (args[0].Listval);
1240 private static Term Fins (Domain domain, Variable vari, Term[] args)
1244 = vari.val.Strval.Insert (args[0].Intval, args[1].Strval);
1245 else if (vari.val.IsList)
1246 vari.val.Listval.InsertRange (args[0].Intval, args[1].Listval);
1248 throw new Exception ("term is not collection: " + vari.val);
1252 private static Term Fdel (Domain domain, Variable vari, Term[] args)
1256 = vari.val.Strval.Remove (args[0].Intval,
1257 args[1].Intval - args[0].Intval);
1259 else if (vari.val.IsList)
1260 vari.val.Listval.RemoveRange (args[0].Intval,
1261 args[1].Intval - args[0].Intval);
1263 throw new Exception ("term is not collection: " + vari.val);
1267 private static Term Fand (Domain domain, Variable vari, Term[] args)
1269 foreach (Term arg in args)
1270 if (! arg.Eval (domain).IsTrue)
1275 private static Term For (Domain domain, Variable vari, Term[] args)
1277 foreach (Term arg in args)
1278 if (arg.Eval (domain).IsTrue)
1283 private static Term Feval (Domain domain, Variable vari, Term[] args)
1285 return (args[0].Eval (domain));
1288 private static Term Fprogn (Domain domain, Variable vari, Term[] args)
1292 foreach (Term arg in args)
1293 result = arg.Eval (domain);
1297 private static Term Fif (Domain domain, Variable vari, Term[] args)
1299 if (args[0].Eval (domain).IsTrue)
1300 return args[1].Eval (domain);
1301 if (args.Length == 2)
1303 return args[2].Eval (domain);
1306 private static Term Fwhen (Domain domain, Variable vari, Term[] args)
1308 if (! args[0].Eval (domain).IsTrue)
1311 for (int i = 1; i < args.Length; i++)
1312 result = args[i].Eval (domain);
1316 private static Term Freturn (Domain domain, Variable vari, Term[] args)
1318 domain.ThrowReturn ();
1319 return args.Length == 0 ? Zero : args[0];
1322 private static Term Fbreak (Domain domain, Variable vari, Term[] args)
1324 domain.ThrowBreak ();
1325 return args.Length == 0 ? Zero : args[0];
1328 private static Term Floop (Domain domain, Variable vari, Term[] args)
1332 domain.Catch (CatchTag.Break);
1333 while (! domain.Thrown)
1334 foreach (Term arg in args)
1336 result = arg.Eval (domain);
1346 private static Term Fwhile (Domain domain, Variable vari, Term[] args)
1350 domain.Catch (CatchTag.Break);
1351 while (! domain.Thrown && args[0].Eval (domain).IsTrue)
1352 for (int i = 1; i < args.Length; i++)
1354 result = args[i].Eval (domain);
1364 private static Term Fcond (Domain domain, Variable vari, Term[] args)
1366 foreach (Term arg in args)
1368 List<Term> list = arg.Listval;
1369 Term result = list[0].Eval (domain);
1373 for (int i = 1; i < list.Count; i++)
1374 result = list[i].Eval (domain);
1381 private static Term Fforeach (Domain domain, Variable vari,
1384 Term result = args[0].Eval (domain);
1387 List<Term> list = result.Listval;
1388 Bindings current = domain.bindings;
1391 domain.Catch (CatchTag.Break);
1392 foreach (Term term in list)
1394 domain.Bind (vari, term);
1396 for (int i = 1; i < args.Length; i++)
1398 result = args[i].Eval (domain);
1403 domain.UnboundTo (current);
1412 private static Term Fquote (Domain domain, Variable vari, Term[] args)
1414 return new Term (args[0]);
1417 private static Term Ftype (Domain domain, Variable vari, Term[] args)
1430 public static Term Fcatch (Domain domain, Variable vari, Term[] args)
1434 domain.Catch (new CatchTag (args[0].Nameval));
1435 result = args[1].Eval (domain);
1442 public static Term Fthrow (Domain domain, Variable vari, Term[] args)
1444 domain.ThrowTag (new CatchTag (args[0].Nameval));
1445 return (args.Length == 1 ? Zero : args[1]);
1448 public class TermValue
1450 public virtual Term Eval (Domain domain) { return new Term (this); }
1453 private class Funcall : TermValue
1455 internal Function func;
1456 internal Variable vari;
1457 internal Term[] args;
1459 public Funcall (XmlNode node, Domain domain)
1462 Name name = node.Name;
1464 if (name == Nfuncall)
1465 name = node.Attributes[0].Value;
1466 else if (node.Attributes[Nvname] != null)
1467 vari = domain.GetVar (node.Attributes[Nvname].Value);
1468 func = domain.GetFunc (name);
1469 XmlNodeList nlist = node.ChildNodes;
1470 int nargs = nlist.Count;
1472 if (nargs < func.min_arg
1473 || (func.max_arg >= 0 && nargs > func.max_arg))
1474 throw new Exception ("Invalid number of arguments to: "
1475 + name + " " + nargs);
1476 args = new Term[nargs];
1477 for (int i = 0; i < nlist.Count; i++)
1478 args[i] = new Term (nlist[i], domain);
1481 public Funcall (Domain domain, Name fname, Name vname, Term[] args)
1483 func = domain.GetFunc (fname);
1484 vari = domain.GetVar (vname);
1488 public override Term Eval (Domain domain)
1490 domain.DebugWrite (true, "(({0}", func.name);
1491 for (int i = 0; i < args.Length; i++)
1492 domain.DebugWrite (false, " {0}", args[i].ToString ());
1493 domain.DebugWrite (false, ")");
1495 Term result = func.Call (domain, vari, args);
1497 domain.DebugWrite (true, " ==> {0})", result.ToString ());
1501 public override string ToString ()
1503 string str = "<funcall fname=\"" + func.name;
1505 return str + "\"/>";
1507 foreach (Term e in args)
1509 return (str + "</funcall>");
1516 public object objval;
1518 public Term (int i) { intval = i; objval = null; }
1519 public Term (Name name) { intval = 0; objval = name; }
1520 public Term (string str) { intval = 0; objval = str; }
1521 public Term (List<Term> list) { intval = 0; objval = list; }
1522 public Term (Term term) { intval = term.intval; objval = term.objval; }
1523 public Term (TermValue obj) { intval = 0; objval = obj; }
1525 public Term (XmlNode node, Domain domain)
1527 Name name = node.Name;
1529 if (name == Ninteger)
1531 intval = parse_integer (node.InnerText);
1537 if (name == Nsymbol)
1538 objval = (Name) node.InnerText;
1539 else if (name == Nstring)
1540 objval = node.InnerText.Clone ();
1541 else if (name == Nvarref)
1542 objval = domain.GetVar ((Name) node.Attributes[0].Value);
1543 else if (name == Nlist)
1545 List<Term> list = new List<Term> ();
1546 for (node = node.FirstChild; node != null;
1547 node = node.NextSibling)
1548 list.Add (new Term (node, domain));
1552 objval = new Funcall (node, domain);
1556 public object Objval {
1559 throw new Exception ("term is an integer: " + this);
1567 throw new Exception ("term is not integer: " + this);
1572 public string Strval {
1575 throw new Exception ("term is not string: " + this);
1576 return (string) objval;
1580 public string Nameval {
1583 throw new Exception ("term is not symbol: " + this);
1584 return (Name) objval;
1588 public List<Term> Listval {
1591 throw new Exception ("term is not list: " + this);
1592 return (List<Term>) objval;
1596 public bool IsTrue {
1598 return (objval == null
1600 : objval is List<Term>
1601 ? (((List<Term>) objval).Count != 0)
1605 public bool IsInt { get { return (objval == null); } }
1606 public bool IsStr { get { return (objval is string); } }
1607 public bool IsName { get { return (objval is Name); } }
1608 public bool IsList { get { return (objval is List<Term>); } }
1610 public bool IsType (Type type)
1612 return (objval == null ? type == typeof (int)
1613 : type == objval.GetType ());
1616 public Term Eval (Domain domain)
1618 if (objval == null || objval is Name || objval is string)
1620 if (objval is List<Term>)
1621 return new Term ((List<Term>) objval);
1622 if (objval is TermValue)
1623 return ((TermValue) objval).Eval (domain);
1624 throw new Exception ("invalid Term object: " + objval);
1627 public static explicit operator int (Term term)
1629 if (term.objval != null)
1630 throw new Exception ("Not an integer term: " + term);
1634 public static explicit operator Name (Term term)
1636 return (Name) term.objval;
1639 public static implicit operator Term (int i)
1641 return new Term (i);
1644 public override string ToString ()
1649 str = "<integer>" + intval + "</integer>";
1650 else if (objval is Name)
1651 str = "<symbol>" + objval + "</symbol>";
1652 else if (objval is string)
1653 str = "<string>" + objval + "</string>";
1654 else if (objval is List<Term>)
1657 foreach (Term e in (List<Term>) objval)
1661 else if (objval is Funcall)
1662 str = "<funcall fname=\"" + ((Funcall) objval).func.name + "\"/>";
1663 else if (objval is Variable)
1664 str = "<variable vname=\"" + ((Variable) objval).name + "\"/>";
1665 else if (objval is Term)
1666 str = "<quote>" + objval + "</quote>";
1668 throw new Exception ("invalid Term object: " + objval);
1673 static private Term Zero = new Term (0);
1674 static private Term One = new Term (1);
1675 static private Term TermInt = new Term (Ninteger);
1676 static private Term TermStr = new Term (Nstring);
1677 static private Term TermName = new Term (Nsymbol);
1678 static private Term TermList = new Term (Nlist);
1679 static private Term TermTerm = new Term ((Name) "term");
1681 internal static int parse_integer (string str)
1683 int len = str.Length;
1684 bool negative = false;
1687 return (len == 0 ? 0 : str[0] - '0');
1694 if ((c == '0' || c == '#') && str[1] == 'x')
1697 for (int idx = 2; idx < len; idx++)
1703 i = i * 16 + (c - '0');
1707 i = i * 16 + (c - 'A');
1711 i = i * 16 + (c - 'a');
1720 for (int idx = 1; idx < len; idx++)
1723 if (c < '0' || c > '9')
1725 i = i * 10 + (c - '0');
1727 return negative ? - i : i;
1730 private Term[] terms;
1732 private void parse_terms (Domain domain, XmlNode node)
1735 for (XmlNode n = node; n != null; n = n.NextSibling)
1736 if (n.NodeType == XmlNodeType.Element)
1738 if (n.Name == Ndefun)
1739 domain.RegisterFunction (n);
1740 else if (n.Name == Ndefvar)
1746 terms = new Term[nterms];
1748 for (XmlNode n = node; n != null; n = n.NextSibling)
1749 if (n.NodeType == XmlNodeType.Element)
1751 if (n.Name == Ndefun)
1753 else if (n.Name != Ndefvar)
1754 terms[i++]= new Term (n, domain);
1758 public Xexpression (Domain domain, XmlNode node)
1760 parse_terms (domain, node);
1763 public Xexpression (Domain domain, string url)
1765 XmlDocument doc = new XmlDocument (Name.Table);
1768 using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
1772 } while (reader.NodeType != XmlNodeType.None
1773 && (reader.NodeType != XmlNodeType.Element
1774 || reader.Name != Nexpr));
1775 if (reader.NodeType == XmlNodeType.None)
1776 throw new Exception ("Node <expr> not found");
1777 node = doc.ReadNode (reader);
1779 parse_terms (domain, node.FirstChild);
1782 public Term Eval (Domain domain)
1788 domain.Catch (CatchTag.Return);
1789 foreach (Term term in terms)
1791 result = term.Eval (domain);
1801 public override string ToString ()
1804 for (int i = 0; i < terms.Length; i++)