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 public 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 public 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 public 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 (Name name, Name[] args, bool args_evalled)
685 Function func = new Function.Lambda (this, name, args, args_evalled)
688 public void Defun (XmlNode node)
690 Name name = node.Attributes[Nfname].Value;
693 if (! functions.TryGetValue (name, out func))
694 func = RegisterFunction (node);
695 ((Function.Lambda) func).SetBody (node, this);
698 public Variable Defvar (XmlNode node)
700 Name name = node.Attributes[0].Value;
704 node = node.FirstChild;
705 if (node.Name == Ndescription)
707 desc = node.InnerText;
708 node = node.NextSibling;
714 Name type = node.Name;
715 XmlNodeList range_list = null;
717 string val = node.InnerText;
719 node = node.NextSibling;
722 range_list = node.ChildNodes;
723 nranges = range_list.Count;
726 if (type == Ninteger)
728 int intval = parse_integer (val);
730 if (range_list != null)
732 range = new int[nranges * 2];
733 for (int i = 0; i < nranges; i++)
735 XmlNode n = range_list[i];
736 if (n.Name == Nrange)
739 = parse_integer (n.FirstChild.InnerText);
741 = parse_integer (n.LastChild.InnerText);
747 = parse_integer (n.InnerText);
752 if (variables.TryGetValue (name, out vari))
754 if (! (vari is Variable.Int))
755 throw new Exception ("Inalid value");
756 vari = vari.Clone ();
757 Term v = new Term (intval);
759 vari.DefaultValue = v;
764 vari = new Variable.Int (name, desc, intval, range);
766 else if (type == Nstring)
768 string[] range = null;
769 if (range_list != null)
771 range = new string[nranges];
772 for (int i = 0; i < nranges; i++)
773 range[i] = range_list[i].InnerText;
776 if (variables.TryGetValue (name, out vari))
778 if (! (vari is Variable.Str))
779 throw new Exception ("Invalid value");
780 vari = vari.Clone ();
781 Term v = new Term (val);
783 vari.DefaultValue = v;
788 vari = new Variable.Str (name, desc, val, range);
790 else if (type == Nsymbol)
793 if (range_list != null)
795 range = new Name[nranges];
796 for (int i = 0; i < nranges; i++)
797 range[i] = range_list[i].InnerText;
800 if (variables.TryGetValue (name, out vari))
802 if (! (vari is Variable.Sym))
803 throw new Exception ("Invalid value");
804 vari = vari.Clone ();
805 Term v = new Term (val);
807 vari.DefaultValue = v;
812 vari = new Variable.Sym (name, desc, val, range);
815 throw new Exception ("Unknown type: " + type);
819 if (variables.TryGetValue (name, out vari))
820 vari = vari.Clone ();
822 vari = new Variable (name, Zero);
824 variables[name] = vari;
828 public Variable Defvar (Variable vari)
830 variables[vari.name] = vari;
834 internal Variable Defvar (Name name)
836 Variable vari = new Variable (name, Zero);
837 variables[name] = vari;
841 internal Function GetFunc (Name name)
845 if (! functions.TryGetValue (name, out func))
846 throw new Exception ("Unknown function: " + name);
850 public bool CopyFunc (Domain domain, Name name)
852 Function func = GetFunc (name);
854 domain.functions[name] = func;
858 public void CopyFunc (Domain domain)
860 foreach (KeyValuePair<Name, Function> kv in functions)
861 domain.functions[kv.Key] = kv.Value;
864 public Variable GetVar (Name name, bool create)
868 if (! variables.TryGetValue (name, out vari))
872 variables[name] = vari = new Variable (name, Zero);
877 public override string ToString ()
879 string str = "<(functions";
880 foreach (KeyValuePair<Name, Function> kv in functions)
882 str += ") (variabls";
883 foreach (KeyValuePair<Name, Variable> kv in variables)
886 if (bindings != null)
887 str += " " + bindings;
889 str += " (" + context + ")";
894 internal void DebugWrite (bool head, string fmt, params string[] arg)
896 if (debug_level > depth)
900 Console.WriteLine ();
901 for (int i = 0; i < depth; i++)
904 Console.Write (fmt, arg);
909 public delegate Term Builtin (Domain domain, Variable vari, Term[] args);
911 private static Domain basic = new Domain ();
913 static Xexpression ()
915 basic.DefSubr (Fset, "set", true, 1, 1, "=");
916 basic.DefSubr (Fnot, "not", false, 1, 1, "!");
917 basic.DefSubr (Fadd, "add", true, 1, -1, "+");
918 basic.DefSubr (Fmul, "mul", true, 1, -1, "*");
919 basic.DefSubr (Fsub, "sub", true, 1, -1, "-");
920 basic.DefSubr (Fdiv, "div", true, 1, -1, "/");
921 basic.DefSubr (Fmod, "mod", true, 1, 2, "%");
922 basic.DefSubr (Flogior, "logior", true, 1, -1, "|");
923 basic.DefSubr (Flogand, "logand", true, 1, -1, "&");
924 basic.DefSubr (Flsh, "lsh", true, 1, 2, "<<");
925 basic.DefSubr (Frsh, "rsh", true, 1, 2, ">>");
926 basic.DefSubr (Feq, "eq", false, 2, -1, "==");
927 basic.DefSubr (Fnoteq, "noteq", false, 2, 2, "!=");
928 basic.DefSubr (Flt, "lt", false, 2, -1, "<");
929 basic.DefSubr (Fle, "le", false, 2, -1, "<=");
930 basic.DefSubr (Fgt, "gt", false, 2, -1, ">");
931 basic.DefSubr (Fge, "ge", false, 2, -1, ">=");
932 basic.DefSubr (Fappend, "append", true, 0, -1);
933 basic.DefSubr (Fconcat, "concat", true, 0, -1);
934 basic.DefSubr (Fnth, "nth", false, 2, 2);
935 basic.DefSubr (Fcopy, "copy", false, 1, 1);
936 basic.DefSubr (Fins, "ins", true, 2, 2);
937 basic.DefSubr (Fdel, "del", true, 2, 2);
938 basic.DefSubr (Feval, "eval", false, 1, 1);
939 basic.DefSubr (Fbreak, "break", false, 0, 1);
940 basic.DefSubr (Freturn, "return", false, 0, 1);
941 basic.DefSpecial (Fand, "and", 1, -1, "&&");
942 basic.DefSpecial (For, "or", 1, -1, "||");
943 basic.DefSpecial (Fprogn, "progn", 0, -1, "expr");
944 basic.DefSpecial (Fif, "if", 2, 3);
945 basic.DefSpecial (Fwhen, "when", 1, -1);
946 basic.DefSpecial (Floop, "loop", 1, -1);
947 basic.DefSpecial (Fwhile, "while", 1, -1);
948 basic.DefSpecial (Fcond, "cond", 1, -1);
949 basic.DefSpecial (Fforeach, "foreach", 2, -1);
950 basic.DefSpecial (Fquote, "quote", 1, 1);
951 basic.DefSpecial (Ftype, "type", 1, 1);
952 basic.DefSpecial (Fcatch, "catch", 2, 2);
953 basic.DefSpecial (Fthrow, "throw", 1, 2);
956 private static Term Fset (Domain domain, Variable vari, Term[] args)
958 vari.Value = args[0];
962 private static Term Fnot (Domain domain, Variable vari, Term[] args)
964 return args[0].IsTrue ? Zero : One;
967 private static Term Fadd (Domain domain, Variable vari, Term[] args)
969 int n = vari == null ? 0 : vari.val.Intval;
971 foreach (Term arg in args)
979 private static Term Fmul (Domain domain, Variable vari, Term[] args)
981 int n = vari == null ? 1 : vari.val.Intval;
982 foreach (Term arg in args)
990 private static Term Fsub (Domain domain, Variable vari, Term[] args)
1001 n = vari.val.Intval;
1004 while (i < args.Length)
1005 n -= (int) args[i++];
1008 vari.val.intval = n;
1012 private static Term Fdiv (Domain domain, Variable vari, Term[] args)
1023 n = vari.val.Intval;
1026 while (i < args.Length)
1027 n /= args[i++].Intval;
1030 vari.val.intval = n;
1034 private static Term Fmod (Domain domain, Variable vari, Term[] args)
1037 return (args[0].Intval % args[1].Intval);
1038 vari.val.intval = vari.val.Intval % args[0].Intval;
1042 private static Term Flogior (Domain domain, Variable vari, Term[] args)
1044 int n = vari == null ? 0 : vari.val.Intval;
1045 foreach (Term arg in args)
1049 vari.val.intval = n;
1053 private static Term Flogand (Domain domain, Variable vari, Term[] args)
1064 n = vari.val.Intval;
1067 while (i < args.Length)
1068 n &= (int) args[i++];
1071 vari.val.intval = n;
1075 private static Term Flsh (Domain domain, Variable vari, Term[] args)
1078 return args[0].Intval << args[1].Intval;
1079 vari.val.intval = vari.val.Intval << args[0].Intval;
1083 private static Term Frsh (Domain domain, Variable vari, Term[] args)
1086 return args[0].Intval >> args[1].Intval;
1087 vari.val.intval = vari.val.Intval >> args[0].Intval;
1091 private static Term Feq (Domain domain, Variable vari, Term[] args)
1095 if (o.objval == null)
1097 for (int i = 1; i < args.Length; i++)
1098 if (args[i].objval != null || args[i].intval != o.intval)
1103 for (int i = 1; i < args.Length; i++)
1104 if (o.objval.Equals (args[i].objval))
1110 private static Term Fnoteq (Domain domain, Variable vari, Term[] args)
1112 return Feq (domain, vari, args);
1115 private static Term Flt (Domain domain, Variable vari, Term[] args)
1117 int n = (int) args[0];
1119 for (int i = 1; i < args.Length; i++)
1121 int n1 = (int) args[i];
1129 private static Term Fle (Domain domain, Variable vari, Term[] args)
1131 int n = (int) args[0];
1132 for (int i = 1; i < args.Length; i++)
1134 int n1 = (int) args[i];
1142 private static Term Fgt (Domain domain, Variable vari, Term[] args)
1144 int n = (int) args[0];
1145 for (int i = 1; i < args.Length; i++)
1147 int n1 = (int) args[i];
1155 private static Term Fge (Domain domain, Variable vari, Term[] args)
1157 int n = (int) args[0];
1158 for (int i = 1; i < args.Length; i++)
1160 int n1 = (int) args[i];
1168 private static Term Fappend (Domain domain, Variable vari, Term[] args)
1173 list = new List<Term> ();
1175 list = vari.val.Listval;
1177 foreach (Term arg in args)
1180 list.AddRange ((List<Term>) arg.objval);
1188 result.objval = list;
1194 private static Term Fconcat (Domain domain, Variable vari, Term[] args)
1201 str = vari.val.Strval;
1203 foreach (Term arg in args)
1206 str += (string) arg.objval;
1207 else if (arg.IsList)
1208 foreach (Term term in (List<Term>) arg.objval)
1209 str += (char) term.Intval;
1211 str += (char) arg.Intval;
1217 result.objval = str;
1220 vari.val.objval = str;
1224 private static Term Fnth (Domain domain, Variable vari, Term[] args)
1230 result.intval = ((string) args[1].objval)[args[0].Intval];
1231 result.objval = null;
1233 else if (args[1].IsList)
1235 result = ((List<Term>) args[1].objval)[args[0].Intval];
1238 throw new Exception ("Term is not enumelable: " + args[1]);
1242 private static Term Fcopy (Domain domain, Variable vari, Term[] args)
1247 result.objval = new List<Term> (args[0].Listval);
1251 private static Term Fins (Domain domain, Variable vari, Term[] args)
1255 = vari.val.Strval.Insert (args[0].Intval, args[1].Strval);
1256 else if (vari.val.IsList)
1257 vari.val.Listval.InsertRange (args[0].Intval, args[1].Listval);
1259 throw new Exception ("term is not collection: " + vari.val);
1263 private static Term Fdel (Domain domain, Variable vari, Term[] args)
1267 = vari.val.Strval.Remove (args[0].Intval,
1268 args[1].Intval - args[0].Intval);
1270 else if (vari.val.IsList)
1271 vari.val.Listval.RemoveRange (args[0].Intval,
1272 args[1].Intval - args[0].Intval);
1274 throw new Exception ("term is not collection: " + vari.val);
1278 private static Term Fand (Domain domain, Variable vari, Term[] args)
1280 foreach (Term arg in args)
1281 if (! arg.Eval (domain).IsTrue)
1286 private static Term For (Domain domain, Variable vari, Term[] args)
1288 foreach (Term arg in args)
1289 if (arg.Eval (domain).IsTrue)
1294 private static Term Feval (Domain domain, Variable vari, Term[] args)
1296 return (args[0].Eval (domain));
1299 private static Term Fprogn (Domain domain, Variable vari, Term[] args)
1303 foreach (Term arg in args)
1304 result = arg.Eval (domain);
1308 private static Term Fif (Domain domain, Variable vari, Term[] args)
1310 if (args[0].Eval (domain).IsTrue)
1311 return args[1].Eval (domain);
1312 if (args.Length == 2)
1314 return args[2].Eval (domain);
1317 private static Term Fwhen (Domain domain, Variable vari, Term[] args)
1319 if (! args[0].Eval (domain).IsTrue)
1322 for (int i = 1; i < args.Length; i++)
1323 result = args[i].Eval (domain);
1327 private static Term Freturn (Domain domain, Variable vari, Term[] args)
1329 domain.ThrowReturn ();
1330 return args.Length == 0 ? Zero : args[0];
1333 private static Term Fbreak (Domain domain, Variable vari, Term[] args)
1335 domain.ThrowBreak ();
1336 return args.Length == 0 ? Zero : args[0];
1339 private static Term Floop (Domain domain, Variable vari, Term[] args)
1343 domain.Catch (CatchTag.Break);
1344 while (! domain.Thrown)
1345 foreach (Term arg in args)
1347 result = arg.Eval (domain);
1357 private static Term Fwhile (Domain domain, Variable vari, Term[] args)
1361 domain.Catch (CatchTag.Break);
1362 while (! domain.Thrown && args[0].Eval (domain).IsTrue)
1363 for (int i = 1; i < args.Length; i++)
1365 result = args[i].Eval (domain);
1375 private static Term Fcond (Domain domain, Variable vari, Term[] args)
1377 foreach (Term arg in args)
1379 List<Term> list = arg.Listval;
1380 Term result = list[0].Eval (domain);
1384 for (int i = 1; i < list.Count; i++)
1385 result = list[i].Eval (domain);
1392 private static Term Fforeach (Domain domain, Variable vari,
1395 Term result = args[0].Eval (domain);
1398 List<Term> list = result.Listval;
1399 Bindings current = domain.bindings;
1402 domain.Catch (CatchTag.Break);
1403 foreach (Term term in list)
1405 domain.Bind (vari, term);
1407 for (int i = 1; i < args.Length; i++)
1409 result = args[i].Eval (domain);
1414 domain.UnboundTo (current);
1423 private static Term Fquote (Domain domain, Variable vari, Term[] args)
1425 return new Term (args[0]);
1428 private static Term Ftype (Domain domain, Variable vari, Term[] args)
1441 public static Term Fcatch (Domain domain, Variable vari, Term[] args)
1445 domain.Catch (new CatchTag (args[0].Nameval));
1446 result = args[1].Eval (domain);
1453 public static Term Fthrow (Domain domain, Variable vari, Term[] args)
1455 domain.ThrowTag (new CatchTag (args[0].Nameval));
1456 return (args.Length == 1 ? Zero : args[1]);
1459 public class TermValue
1461 public virtual Term Eval (Domain domain) { return new Term (this); }
1464 private class Funcall : TermValue
1466 internal Function func;
1467 internal Variable vari;
1468 internal Term[] args;
1470 public Funcall (XmlNode node, Domain domain)
1473 Name name = node.Name;
1475 if (name == Nfuncall)
1476 name = node.Attributes[0].Value;
1477 else if (node.Attributes[Nvname] != null)
1478 vari = domain.GetVar (node.Attributes[Nvname].Value, true);
1479 func = domain.GetFunc (name);
1480 XmlNodeList nlist = node.ChildNodes;
1481 int nargs = nlist.Count;
1483 if (nargs < func.min_arg
1484 || (func.max_arg >= 0 && nargs > func.max_arg))
1485 throw new Exception ("Invalid number of arguments to: "
1486 + name + " " + nargs);
1487 args = new Term[nargs];
1488 for (int i = 0; i < nlist.Count; i++)
1489 args[i] = new Term (nlist[i], domain);
1492 public Funcall (Domain domain, Name fname, Term[] args)
1494 func = domain.GetFunc (fname);
1498 public Funcall (Domain domain, Name fname, Name vname, Term[] args)
1500 func = domain.GetFunc (fname);
1501 vari = domain.GetVar (vname, true);
1505 public override Term Eval (Domain domain)
1507 domain.DebugWrite (true, "(({0}", func.name);
1508 for (int i = 0; i < args.Length; i++)
1509 domain.DebugWrite (false, " {0}", args[i].ToString ());
1510 domain.DebugWrite (false, ")");
1512 Term result = func.Call (domain, vari, args);
1514 domain.DebugWrite (true, " ==> {0})", result.ToString ());
1518 public override string ToString ()
1520 string str = "<funcall fname=\"" + func.name;
1522 return str + "\"/>";
1524 foreach (Term e in args)
1526 return (str + "</funcall>");
1533 public object objval;
1535 public Term (int i) { intval = i; objval = null; }
1536 public Term (Name name) { intval = 0; objval = name; }
1537 public Term (string str) { intval = 0; objval = str; }
1538 public Term (List<Term> list) { intval = 0; objval = list; }
1539 public Term (Term term) { intval = term.intval; objval = term.objval; }
1540 public Term (TermValue obj) { intval = 0; objval = obj; }
1542 public Term (XmlNode node, Domain domain)
1544 Name name = node.Name;
1546 if (name == Ninteger)
1548 intval = parse_integer (node.InnerText);
1554 if (name == Nsymbol)
1555 objval = (Name) node.InnerText;
1556 else if (name == Nstring)
1557 objval = node.InnerText.Clone ();
1558 else if (name == Nvarref)
1559 objval = domain.GetVar ((Name) node.Attributes[0].Value, true);
1560 else if (name == Nlist)
1562 List<Term> list = new List<Term> ();
1563 for (node = node.FirstChild; node != null;
1564 node = node.NextSibling)
1565 list.Add (new Term (node, domain));
1569 objval = new Funcall (node, domain);
1573 public object Objval {
1576 throw new Exception ("term is an integer: " + this);
1584 throw new Exception ("term is not integer: " + this);
1589 public string Strval {
1592 throw new Exception ("term is not string: " + this);
1593 return (string) objval;
1597 public string Nameval {
1600 throw new Exception ("term is not symbol: " + this);
1601 return (Name) objval;
1605 public List<Term> Listval {
1608 throw new Exception ("term is not list: " + this);
1609 return (List<Term>) objval;
1613 public bool IsTrue {
1615 return (objval == null
1617 : objval is List<Term>
1618 ? (((List<Term>) objval).Count != 0)
1622 public bool IsInt { get { return (objval == null); } }
1623 public bool IsStr { get { return (objval is string); } }
1624 public bool IsName { get { return (objval is Name); } }
1625 public bool IsList { get { return (objval is List<Term>); } }
1627 public bool IsType (Type type)
1629 return (objval == null ? type == typeof (int)
1630 : type == objval.GetType ());
1633 public Term Eval (Domain domain)
1635 if (objval == null || objval is Name || objval is string)
1637 if (objval is List<Term>)
1638 return new Term ((List<Term>) objval);
1639 if (objval is TermValue)
1640 return ((TermValue) objval).Eval (domain);
1641 throw new Exception ("invalid Term object: " + objval);
1644 public static explicit operator int (Term term)
1646 if (term.objval != null)
1647 throw new Exception ("Not an integer term: " + term);
1651 public static explicit operator Name (Term term)
1653 return (Name) term.objval;
1656 public static implicit operator Term (int i)
1658 return new Term (i);
1661 public override string ToString ()
1666 str = "<integer>" + intval + "</integer>";
1667 else if (objval is Name)
1668 str = "<symbol>" + objval + "</symbol>";
1669 else if (objval is string)
1670 str = "<string>" + objval + "</string>";
1671 else if (objval is List<Term>)
1674 foreach (Term e in (List<Term>) objval)
1678 else if (objval is Funcall)
1679 str = "<funcall fname=\"" + ((Funcall) objval).func.name + "\"/>";
1680 else if (objval is Variable)
1681 str = "<variable vname=\"" + ((Variable) objval).name + "\"/>";
1682 else if (objval is Term)
1683 str = "<quote>" + objval + "</quote>";
1685 throw new Exception ("invalid Term object: " + objval);
1690 static private Term Zero = new Term (0);
1691 static private Term One = new Term (1);
1692 static private Term TermInt = new Term (Ninteger);
1693 static private Term TermStr = new Term (Nstring);
1694 static private Term TermName = new Term (Nsymbol);
1695 static private Term TermList = new Term (Nlist);
1696 static private Term TermTerm = new Term ((Name) "term");
1698 internal static int parse_integer (string str)
1700 int len = str.Length;
1701 bool negative = false;
1704 return (len == 0 ? 0 : str[0] - '0');
1711 if ((c == '0' || c == '#') && str[1] == 'x')
1714 for (int idx = 2; idx < len; idx++)
1720 i = i * 16 + (c - '0');
1724 i = i * 16 + (c - 'A');
1728 i = i * 16 + (c - 'a');
1737 for (int idx = 1; idx < len; idx++)
1740 if (c < '0' || c > '9')
1742 i = i * 10 + (c - '0');
1744 return negative ? - i : i;
1747 private Term[] terms;
1749 private void parse_terms (Domain domain, XmlNode node)
1752 for (XmlNode n = node; n != null; n = n.NextSibling)
1753 if (n.NodeType == XmlNodeType.Element)
1755 if (n.Name == Ndefun)
1756 domain.RegisterFunction (n);
1757 else if (n.Name == Ndefvar)
1763 terms = new Term[nterms];
1765 for (XmlNode n = node; n != null; n = n.NextSibling)
1766 if (n.NodeType == XmlNodeType.Element)
1768 if (n.Name == Ndefun)
1770 else if (n.Name != Ndefvar)
1771 terms[i++]= new Term (n, domain);
1775 public Xexpression (Domain domain, XmlNode node)
1777 parse_terms (domain, node);
1780 public Xexpression (Domain domain, string url)
1782 XmlDocument doc = new XmlDocument (Name.Table);
1785 using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
1789 } while (reader.NodeType != XmlNodeType.None
1790 && (reader.NodeType != XmlNodeType.Element
1791 || reader.Name != Nexpr));
1792 if (reader.NodeType == XmlNodeType.None)
1793 throw new Exception ("Node <expr> not found");
1794 node = doc.ReadNode (reader);
1796 parse_terms (domain, node.FirstChild);
1799 public Term Eval (Domain domain)
1805 domain.Catch (CatchTag.Return);
1806 foreach (Term term in terms)
1808 result = term.Eval (domain);
1818 public override string ToString ()
1821 for (int i = 0; i < terms.Length; i++)