{
private static NameTable nt = new NameTable ();
- private string name;
+ internal string name;
public Name (string str)
{
private static Name Nexpr = "expr";
private static Name Nfuncall = "funcall";
- private static Name Nvariable = "variable";
+ private static Name Nvarref = "varref";
private static Name Ninteger = "integer";
private static Name Nstring = "string";
private static Name Nsymbol = "symbol";
private static Name Nfname = "fname";
private static Name Nargs = "args";
private static Name Nargs_unevalled = "args-unevalled";
+ private static Name Nfixed = "fixed";
private static Name Noptional = "optional";
private static Name Nrest = "rest";
- private static Name Nbody = "body";
private static Name Ndefvar = "defvar";
+ private static Name Nvname = "vname";
private static Name Ndescription = "description";
private static Name Nrange = "range";
- private static Name Nprogn = "progn";
-
- internal abstract class Function
+ public abstract class Function
{
public Name name;
public int min_arg, max_arg;
this.max_arg = max_arg;
}
- public abstract Term Call (Domain domain, Term[] args);
+ public abstract Term Call (Domain domain, Variable vari, Term[] args);
public override string ToString ()
{
internal class Subroutine : Function
{
public Builtin builtin;
+ public bool setvar;
- public Subroutine (Builtin builtin, Name name,
+ public Subroutine (Builtin builtin, Name name, bool setvar,
int min_arg, int max_arg)
: base (name, min_arg, max_arg)
{
this.builtin = builtin;
}
- public override Term Call (Domain domain, Term[] args)
+ public override Term Call (Domain domain, Variable vari, Term[] args)
{
- Term[] newargs = new Term[args.Length];
-
+ args = (Term[]) args.Clone ();
for (int i = 0; i < args.Length; i++)
- newargs[i] = args[i].Eval (domain);
- return builtin (domain, newargs);
+ {
+ args[i] = args[i].Eval (domain);
+ if (domain.Thrown)
+ return args[i];
+ }
+ return builtin (domain, vari, args);
}
}
this.builtin = builtin;
}
- public override Term Call (Domain domain, Term[] args)
+ public override Term Call (Domain domain, Variable vari, Term[] args)
{
- return builtin (domain, args);
+ return builtin (domain, vari, args);
}
}
internal class Lambda : Function
{
internal bool args_evalled;
- internal Term[] args;
+ internal Variable[] args;
internal Term[] body;
- public Lambda (XmlNode node)
+ public Lambda (XmlNode node, Domain domain)
{
- int nargs = 0, noptions = 0, nrest = 0;
+ int nfixed = 0;
+ int noptional = 0;
+ int nrest = 0;
name = node.Attributes[Nfname].Value;
node = node.FirstChild;
args_evalled = node.Name == Nargs;
for (n = node.FirstChild; n != null; n = n.NextSibling)
{
- if (n.Name != Nsymbol)
- break;
- nargs++;
+ if (n.Name == Nfixed)
+ nfixed++;
+ else if (n.Name == Noptional)
+ noptional++;
+ else if (n.Name == Nrest)
+ nrest++;
+ else
+ throw new Exception ("Invalid argument type: " + n);
}
- if (n != null && n.Name == Noptional)
- for (n = n.NextSibling; n != null; n = n.NextSibling)
- {
- if (n.Name == Nrest)
- break;
- noptions++;
- }
- if (n != null)
- nrest++;
- min_arg = nargs;
- max_arg = nargs + noptions + nrest;
- args = new Term[max_arg];
+ min_arg = nfixed;
+ max_arg = nfixed + noptional + nrest;
+ args = new Variable[max_arg];
n = node.FirstChild;
for (int i = 0; i < max_arg; n = n.NextSibling)
- if (n.Name == Nsymbol)
- args[i++] = new Term (n, null);
+ args[i++] = domain.Defvar ((Name) n.Attributes[0].Value);
if (nrest == 1)
max_arg = - max_arg;
}
public void SetBody (XmlNode node, Domain domain)
{
-
- for (node = node.FirstChild; node != null && node.Name != Nbody;
- node = node.NextSibling);
- if (node != null)
+ for (node = node.FirstChild; node != null; node = node.NextSibling)
+ if (node.Name != Ndescription
+ && node.Name != Nargs
+ && node.Name != Nargs_unevalled)
+ break;
+ int nterms = 0;
+ for (XmlNode n = node; n != null; n = n.NextSibling)
+ nterms++;
+ if (nterms > 0)
{
- XmlNodeList nlist = node.ChildNodes;
-
- body = new Term[nlist.Count];
- for (int i = 0; i < nlist.Count; i++)
- body[i] = new Term (nlist[i], domain);
+ body = new Term[nterms];
+ for (nterms = 0; node != null; node = node.NextSibling, nterms++)
+ body[nterms] = new Term (node, domain);
}
}
- public override Term Call (Domain domain, Term[] args)
+ public override Term Call (Domain domain, Variable vari, Term[] args)
{
Bindings current = domain.bindings;
Term result = Zero;
args = newargs;
}
for (i = 0; i < min_arg; i++)
+ domain.Bind (this.args[i], args[i]);
+ if (body != null)
{
- Variable vari = domain.GetVar ((Name) this.args[i]);
- domain.Bind (vari, args[i]);
+ try {
+ if (args_evalled)
+ domain.Catch (CatchTag.Return);
+ foreach (Term term in body)
+ {
+ result = term.Eval (domain);
+ if (domain.Thrown)
+ return result;
+ }
+ } finally {
+ if (args_evalled)
+ domain.Uncatch ();
+ }
}
- if (body != null)
- foreach (Term term in body)
- result = term.Eval (domain);
} finally {
domain.UnboundTo (current);
}
}
}
- internal abstract class Variable
+ public class Variable : TermValue
{
public readonly Name name;
+ public string desc;
+ internal Term default_val;
internal Term val;
+ object range;
- public Variable (Name name, Term term)
+ public Variable (Name name, Term value)
{
this.name = name;
- Value = term;
+ val = value;
+ default_val = Zero;
+ }
+
+ public virtual bool ValueP (Term val) { return true; }
+
+ public Variable Clone ()
+ {
+ Variable v = new Variable (name, val);
+ v.desc = desc;
+ v.default_val = default_val;
+ v.range = range;
+ return v;
}
public Term Value
{
get { return val; }
- set
- {
- if (! ValueP (value))
- throw new Exception ("Invalid value of " + name + ": " + value);
- val = value;
- }
+ set {
+ if (! ValueP (value))
+ throw new Exception ("Invalid value: " + value);
+ val = value;
+ }
}
- public abstract bool ValueP (Term term);
+ public Term DefaultValue
+ {
+ get { return default_val; }
+ set {
+ if (! ValueP (value))
+ throw new Exception ("Invalid value: " + value);
+ default_val = value;
+ }
+ }
+
+ public virtual object Range
+ {
+ get { return range; }
+ set { range = value; }
+ }
+
+ public override Term Eval (Domain domain) { return val; }
public override string ToString () { return name + "(" + val + ")"; }
- internal class Int : Variable
+ public class Int : Variable
{
- public struct Range
- {
- public int from, to;
- }
+ public int[] range;
- public Range[] ranges;
+ private static bool SubsetP (int[] r1, int[] r2)
+ {
+ if (r2 == null)
+ return true;
+ for (int i = 0; i < r1.Length; i += 2)
+ {
+ int j;
+ for (j = 0; j < r2.Length; j += 2)
+ if (r2[j] <= r1[i] && r2[j + 1] >= r1[i + 1])
+ break;
+ if (j >= r2.Length)
+ return false;
+ }
+ return true;
+ }
+
+ private static bool SubsetP (int val, int[] r)
+ {
+ if (r == null)
+ return true;
+ for (int i = 0; i < r.Length; i += 2)
+ if (r[i] <= val && r[i + 1] >= val)
+ return true;
+ return false;
+ }
- public Int (Name name, int i) : base (name, new Term (i)) { }
+ public Int (Name name, string description, int value, int[] range)
+ : base (name, new Term (value))
+ {
+ if (! SubsetP (value, range))
+ throw new Exception ("Invalid value: " + value);
+ desc = description;
+ default_val = val;
+ this.range = range;
+ }
public override bool ValueP (Term term)
{
- int i;
-
- if (term.objval != null)
+ if (! term.IsInt)
return false;
- if (ranges == null)
- return true;
- i = term.intval;
- foreach (Range r in ranges)
- if (i >= r.from && i <= r.to)
- return true;
- return false;
+ return SubsetP (term.Intval, range);
+ }
+
+ public override object Range {
+ get { return range; }
+ set {
+ int[] r = (int[]) value;
+ if (! SubsetP (r, range)
+ || ! SubsetP (val.Intval, r)
+ || ! SubsetP (default_val.Intval, r))
+ throw new Exception ("Invalid range");
+ range = r;
+ }
}
}
- internal class Str : Variable
+ public class Str : Variable
{
- public string[] ranges;
+ public string[] range;
- public Str (Name name, string str) : base (name, new Term (str)) { }
+ private static bool SubsetP (string[] r1, string[] r2)
+ {
+ foreach (string s in r1)
+ if (! SubsetP (s, r2))
+ return false;
+ return true;
+ }
+
+ private static bool SubsetP (string str, string[] r)
+ {
+ foreach (string s in r)
+ if (str == s)
+ return true;
+ return false;
+ }
+
+ public Str (Name name, string description, string value, string[] range)
+ : base (name, new Term (value))
+ {
+ if (! SubsetP (value, range))
+ throw new Exception ("Invalid value: " + value);
+ desc = description;
+ default_val = val;
+ this.range = range;
+ }
public override bool ValueP (Term term)
{
if (! (term.objval is string))
return false;
- if (ranges == null)
- return true;
- string str = (string) term.objval;
- foreach (string s in ranges)
- if (s == str)
- return true;
- return false;
+ return SubsetP (term.Strval, range);
+ }
+
+ public override object Range {
+ get { return range; }
+ set {
+ string[] r = (string[]) value;
+ if (! SubsetP (r, range)
+ || ! SubsetP (val.Strval, r)
+ || ! SubsetP (default_val.Strval, r))
+ throw new Exception ("Invalid range");
+ range = r;
+ }
}
}
- internal class Misc : Variable
+ public class Sym : Variable
{
- public Misc (Name name, Term term) : base (name, term) { }
+ public Name[] range;
+
+ private static bool SubsetP (Name[] r1, Name[] r2)
+ {
+ foreach (Name n in r1)
+ if (! SubsetP (n, r2))
+ return false;
+ return true;
+ }
+
+ private static bool SubsetP (Name name, Name[] r)
+ {
+ foreach (Name n in r)
+ if (name == n)
+ return true;
+ return false;
+ }
+
+ public Sym (Name name, string description, Name value, Name[] range)
+ : base (name, new Term (value))
+ {
+ if (! SubsetP (value, range))
+ throw new Exception ("Invalid value: " + value);
+ desc = description;
+ default_val = val;
+ this.range = range;
+ }
+
+ public override bool ValueP (Term term)
+ {
+ if (! (term.objval is Name))
+ return false;
+ return SubsetP (term.Nameval, range);
+ }
- public override bool ValueP (Term term) { return true; }
+ public override object Range {
+ get { return range; }
+ set {
+ Name[] r = (Name[]) value;
+ if (! SubsetP (r, range)
+ || ! SubsetP (val.Nameval, r)
+ || ! SubsetP (default_val.Nameval, r))
+ throw new Exception ("Invalid range");
+ range = r;
+ }
+ }
}
}
}
#endif
+ internal class CatchTag : IEquatable<CatchTag>
+ {
+ private object val;
+
+ public CatchTag (Name name) { val = name.name; }
+ private CatchTag (int i) { val = i; }
+
+ public static CatchTag Return = new CatchTag (0);
+ public static CatchTag Break = new CatchTag (1);
+
+ public static bool operator== (CatchTag t1, CatchTag t2)
+ { return t1.val == t2.val; }
+
+ public static bool operator!= (CatchTag t1, CatchTag t2)
+ { return t1.val != t2.val; }
+
+ public bool Equals (CatchTag tag) { return this.val == tag.val; }
+ public override bool Equals (object val) { return this.val == val; }
+
+ public override int GetHashCode () { return val.GetHashCode (); }
+ }
+
public class Domain
{
public object context;
public int depth = 0;
internal Dictionary<Name, Function> functions;
+ internal Dictionary<Name, Dictionary<Name, Function>>
+ modules = new Dictionary<Name, Dictionary<Name, Function>> ();
internal Dictionary<Name, Variable> variables;
internal Bindings bindings;
+ private Stack<CatchTag> catch_stack = new Stack<CatchTag> ();
+ private int catch_count = 0;
internal Domain ()
{
bindings = bindings.UnboundTo (boundary);
}
- public void DefSubr (Builtin builtin, string str,
+ internal void Catch (CatchTag tag)
+ {
+ catch_stack.Push (tag);
+ catch_count++;
+ }
+
+ internal void Uncatch ()
+ {
+ catch_stack.Pop ();
+ if (catch_count > catch_stack.Count)
+ catch_count--;
+ }
+
+ internal bool Thrown {
+ get { return catch_count < catch_stack.Count; }
+ }
+
+ internal void ThrowReturn ()
+ {
+ foreach (CatchTag tag in catch_stack)
+ {
+ catch_count--;
+ if (tag == CatchTag.Return)
+ break;
+ }
+ }
+
+ internal void ThrowBreak ()
+ {
+ if (catch_stack.Peek () != CatchTag.Break)
+ throw new Exception ("No outer loop to break");
+ catch_count--;
+ }
+
+ internal void ThrowTag (CatchTag tag)
+ {
+ foreach (CatchTag elt in catch_stack)
+ {
+ catch_count--;
+ if (elt == tag)
+ break;
+ }
+ }
+
+ public void DefSubr (Builtin builtin, string str, bool setvar,
int min_arg, int max_arg, params string[] aliases)
{
Name name = str;
- Function func = new Function.Subroutine (builtin, name,
+ Function func = new Function.Subroutine (builtin, name, setvar,
min_arg, max_arg);
functions[name] = func;
foreach (string a in aliases)
internal Function.Lambda RegisterFunction (XmlNode node)
{
- Function.Lambda lambda = new Function.Lambda (node);
+ Function.Lambda lambda = new Function.Lambda (node, this);
functions[lambda.name] = lambda;
return lambda;
}
- internal Function Defun (XmlNode node)
+ public void Defun (Name name, Name[] args, bool args_evalled)
+ {
+ Function func = new Function.Lambda (this, name, args, args_evalled)
+ }
+
+ public void Defun (XmlNode node)
{
Name name = node.Attributes[Nfname].Value;
Function func;
if (! functions.TryGetValue (name, out func))
func = RegisterFunction (node);
((Function.Lambda) func).SetBody (node, this);
- return func;
}
- public void Defvar (XmlNode node)
+ public Variable Defvar (XmlNode node)
{
Name name = node.Attributes[0].Value;
+ String desc;
Variable vari;
node = node.FirstChild;
if (node.Name == Ndescription)
- node = node.NextSibling;
+ {
+ desc = node.InnerText;
+ node = node.NextSibling;
+ }
+ else
+ desc = null;
if (node != null)
{
Name type = node.Name;
if (type == Ninteger)
{
- Variable.Int vi = new Variable.Int (name, parse_integer (val));
+ int intval = parse_integer (val);
+ int[] range = null;
if (range_list != null)
{
- vi.ranges = new Variable.Int.Range[nranges];
-
+ range = new int[nranges * 2];
for (int i = 0; i < nranges; i++)
{
XmlNode n = range_list[i];
-
if (n.Name == Nrange)
{
- vi.ranges[i].from =
- parse_integer (n.FirstChild.InnerText);
- vi.ranges[i].to =
- parse_integer (n.LastChild.InnerText);
+ range[i * 2]
+ = parse_integer (n.FirstChild.InnerText);
+ range[i * 2 + 1]
+ = parse_integer (n.LastChild.InnerText);
}
else
{
- int num = parse_integer (n.InnerText);
- vi.ranges[i].from = vi.ranges[i].to = num;
+ range[i * 2]
+ = range[i * 2 + 1]
+ = parse_integer (n.InnerText);
}
}
}
- vari = vi;
+
+ if (variables.TryGetValue (name, out vari))
+ {
+ if (! (vari is Variable.Int))
+ throw new Exception ("Inalid value");
+ vari = vari.Clone ();
+ Term v = new Term (intval);
+ vari.Value = v;
+ vari.DefaultValue = v;
+ if (range != null)
+ vari.Range = range;
+ }
+ else
+ vari = new Variable.Int (name, desc, intval, range);
}
else if (type == Nstring)
{
- Variable.Str vs = new Variable.Str (name, val);
+ string[] range = null;
if (range_list != null)
- vs.ranges = new string[nranges];
- for (int i = 0; i < nranges; i++)
- vs.ranges[i] = range_list[i].Value;
- vari = vs;
+ {
+ range = new string[nranges];
+ for (int i = 0; i < nranges; i++)
+ range[i] = range_list[i].InnerText;
+ }
+
+ if (variables.TryGetValue (name, out vari))
+ {
+ if (! (vari is Variable.Str))
+ throw new Exception ("Invalid value");
+ vari = vari.Clone ();
+ Term v = new Term (val);
+ vari.Value = v;
+ vari.DefaultValue = v;
+ if (range != null)
+ vari.Range = range;
+ }
+ else
+ vari = new Variable.Str (name, desc, val, range);
+ }
+ else if (type == Nsymbol)
+ {
+ Name[] range = null;
+ if (range_list != null)
+ {
+ range = new Name[nranges];
+ for (int i = 0; i < nranges; i++)
+ range[i] = range_list[i].InnerText;
+ }
+
+ if (variables.TryGetValue (name, out vari))
+ {
+ if (! (vari is Variable.Sym))
+ throw new Exception ("Invalid value");
+ vari = vari.Clone ();
+ Term v = new Term (val);
+ vari.Value = v;
+ vari.DefaultValue = v;
+ if (range != null)
+ vari.Range = range;
+ }
+ else
+ vari = new Variable.Sym (name, desc, val, range);
}
else
throw new Exception ("Unknown type: " + type);
}
else
- vari = new Variable.Misc (name, Zero);
+ {
+ if (variables.TryGetValue (name, out vari))
+ vari = vari.Clone ();
+ else
+ vari = new Variable (name, Zero);
+ }
+ variables[name] = vari;
+ return vari;
+ }
+
+ public Variable Defvar (Variable vari)
+ {
+ variables[vari.name] = vari;
+ return vari;
+ }
+
+ internal Variable Defvar (Name name)
+ {
+ Variable vari = new Variable (name, Zero);
variables[name] = vari;
+ return vari;
}
internal Function GetFunc (Name name)
domain.functions[kv.Key] = kv.Value;
}
- internal Variable GetVar (Name name)
+ public Variable GetVar (Name name, bool create)
{
Variable vari;
if (! variables.TryGetValue (name, out vari))
- variables[name] = vari = new Variable.Misc (name, Zero);
+ {
+ if (! create)
+ return null;
+ variables[name] = vari = new Variable (name, Zero);
+ }
return vari;
}
}
}
- public delegate Term Builtin (Domain domain, Term[] args);
+ public delegate Term Builtin (Domain domain, Variable vari, Term[] args);
private static Domain basic = new Domain ();
- internal static Function Fprogn;
-
static Xexpression ()
{
- basic.DefSubr (set_value, "set", 2, 2, "=");
- basic.DefSpecial (and, "and", 1, -1, "&&");
- basic.DefSpecial (or, "or", 1, -1, "||");
- basic.DefSubr (not, "not", 1, 1, "!");
- basic.DefSubr (add, "add", 2, -1, "+");
- basic.DefSubr (mul, "mul", 2, -1, "*");
- basic.DefSubr (sub, "sub", 1, -1, "-");
- basic.DefSubr (div, "div", 2, -1, "/");
- basic.DefSubr (mod, "mod", 2, 2, "%");
- basic.DefSubr (logior, "logior", 2, -1, "|");
- basic.DefSubr (logand, "logand", 2, -1, "&");
- basic.DefSubr (add_set, "add-set", 2, -1, "+=");
- basic.DefSubr (mul_set, "mul-set", 2, -1, "*=");
- basic.DefSubr (sub_set, "sub-set", 2, -1, "-=");
- basic.DefSubr (div_set, "div-set", 2, -1, "/=");
- basic.DefSubr (mod_set, "mod-set", 2, 2, "%=");
- basic.DefSubr (logior_set, "logior-set", 2, -1, "|=");
- basic.DefSubr (logand_set, "logand-set", 2, -1, "&=");
- basic.DefSubr (lsh, "lsh", 2, 2, "<<");
- basic.DefSubr (rsh, "rsh", 2, 2, ">>");
- basic.DefSubr (lsh_set, "lsh-set", 2, 2, "<<=");
- basic.DefSubr (rsh_set, "rsh-set", 2, 2, ">>=");
- basic.DefSubr (eq, "eq", 2, -1, "==");
- basic.DefSubr (noteq, "noteq", 2, 2, "!=");
- basic.DefSubr (less_than, "lt", 2, -1, "<");
- basic.DefSubr (less_eq, "le", 2, -1, "<=");
- basic.DefSubr (greater_than, "gt", 2, -1, ">");
- basic.DefSubr (greater_eq, "ge", 2, -1, ">=");
- basic.DefSubr (append, "append", 0, -1);
- basic.DefSubr (concat, "concat", 0, -1);
- basic.DefSubr (nth, "nth", 2, 2);
- basic.DefSubr (copy, "copy", 1, 1);
- basic.DefSubr (ins, "ins", 3, 3);
- basic.DefSubr (del, "del", 3, 3);
- basic.DefSubr (eval_clause, "eval", 1, 1);
- basic.DefSpecial (quote_clause, "quote", 1, 1);
- basic.DefSpecial (progn_clause, "progn", 0, -1, "expr");
- basic.DefSpecial (if_clause, "if", 2, 3);
- basic.DefSpecial (when_clause, "when", 1, -1);
- basic.DefSpecial (while_clause, "while", 1, -1);
- basic.DefSpecial (cond_clause, "cond", 1, -1);
- basic.DefSpecial (foreach_clause, "foreach", 3, -1);
-
- Fprogn = basic.GetFunc (Nprogn);
+ basic.DefSubr (Fset, "set", true, 1, 1, "=");
+ basic.DefSubr (Fnot, "not", false, 1, 1, "!");
+ basic.DefSubr (Fadd, "add", true, 1, -1, "+");
+ basic.DefSubr (Fmul, "mul", true, 1, -1, "*");
+ basic.DefSubr (Fsub, "sub", true, 1, -1, "-");
+ basic.DefSubr (Fdiv, "div", true, 1, -1, "/");
+ basic.DefSubr (Fmod, "mod", true, 1, 2, "%");
+ basic.DefSubr (Flogior, "logior", true, 1, -1, "|");
+ basic.DefSubr (Flogand, "logand", true, 1, -1, "&");
+ basic.DefSubr (Flsh, "lsh", true, 1, 2, "<<");
+ basic.DefSubr (Frsh, "rsh", true, 1, 2, ">>");
+ basic.DefSubr (Feq, "eq", false, 2, -1, "==");
+ basic.DefSubr (Fnoteq, "noteq", false, 2, 2, "!=");
+ basic.DefSubr (Flt, "lt", false, 2, -1, "<");
+ basic.DefSubr (Fle, "le", false, 2, -1, "<=");
+ basic.DefSubr (Fgt, "gt", false, 2, -1, ">");
+ basic.DefSubr (Fge, "ge", false, 2, -1, ">=");
+ basic.DefSubr (Fappend, "append", true, 0, -1);
+ basic.DefSubr (Fconcat, "concat", true, 0, -1);
+ basic.DefSubr (Fnth, "nth", false, 2, 2);
+ basic.DefSubr (Fcopy, "copy", false, 1, 1);
+ basic.DefSubr (Fins, "ins", true, 2, 2);
+ basic.DefSubr (Fdel, "del", true, 2, 2);
+ basic.DefSubr (Feval, "eval", false, 1, 1);
+ basic.DefSubr (Fbreak, "break", false, 0, 1);
+ basic.DefSubr (Freturn, "return", false, 0, 1);
+ basic.DefSpecial (Fand, "and", 1, -1, "&&");
+ basic.DefSpecial (For, "or", 1, -1, "||");
+ basic.DefSpecial (Fprogn, "progn", 0, -1, "expr");
+ basic.DefSpecial (Fif, "if", 2, 3);
+ basic.DefSpecial (Fwhen, "when", 1, -1);
+ basic.DefSpecial (Floop, "loop", 1, -1);
+ basic.DefSpecial (Fwhile, "while", 1, -1);
+ basic.DefSpecial (Fcond, "cond", 1, -1);
+ basic.DefSpecial (Fforeach, "foreach", 2, -1);
+ basic.DefSpecial (Fquote, "quote", 1, 1);
+ basic.DefSpecial (Ftype, "type", 1, 1);
+ basic.DefSpecial (Fcatch, "catch", 2, 2);
+ basic.DefSpecial (Fthrow, "throw", 1, 2);
}
- private static Term set_value (Domain domain, Term[] args)
+ private static Term Fset (Domain domain, Variable vari, Term[] args)
{
- Variable vari = domain.GetVar ((Name) args[0]);
-
- vari.Value = args[1];
+ vari.Value = args[0];
return vari.val;
}
- private static Term and (Domain domain, Term[] args)
- {
- foreach (Term arg in args)
- if (! arg.Eval (domain).IsTrue)
- return Zero;
- return One;
- }
-
- private static Term or (Domain domain, Term[] args)
- {
- foreach (Term arg in args)
- if (arg.Eval (domain).IsTrue)
- return One;
- return Zero;
- }
-
- private static Term not (Domain domain, Term[] args)
+ private static Term Fnot (Domain domain, Variable vari, Term[] args)
{
return args[0].IsTrue ? Zero : One;
}
- private static Term add (Domain domain, Term[] args)
+ private static Term Fadd (Domain domain, Variable vari, Term[] args)
{
- int n = 0;
+ int n = vari == null ? 0 : vari.val.Intval;
+
foreach (Term arg in args)
n += (int) arg;
- return n;
+ if (vari == null)
+ return n;
+ vari.val.intval = n;
+ return vari.val;
}
- private static Term mul (Domain domain, Term[] args)
+ private static Term Fmul (Domain domain, Variable vari, Term[] args)
{
- int n = 1;
+ int n = vari == null ? 1 : vari.val.Intval;
foreach (Term arg in args)
n *= (int) arg;
- return n;
- }
-
- private static Term sub (Domain domain, Term[] args)
- {
- int n = (int) args[0];
- if (args.Length == 1)
- return - n;
- for (int i = 1; i < args.Length; i++)
- n -= (int) args[i];
- return n;
- }
-
- private static Term div (Domain domain, Term[] args)
- {
- int n = (int) args[0];
- for (int i = 1; i < args.Length; i++)
- n /= (int) args[i];
- return n;
- }
-
- private static Term mod (Domain domain, Term[] args)
- {
- return ((int) args[0] % (int) args[1]);
- }
-
- private static Term logior (Domain domain, Term[] args)
- {
- int n = 0;
- foreach (Term arg in args)
- n |= (int) arg;
- return n;
- }
-
- private static Term logand (Domain domain, Term[] args)
- {
- int n = (int) args[0];
- for (int i = 1; i < args.Length; i++)
- n &= (int) args[i];
- return n;
- }
-
- private static Term add_set (Domain domain, Term[] args)
- {
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
-
- for (int i = 1; i < args.Length; i++)
- n += (int) args[i];
- vari.val = n;
+ if (vari == null)
+ return n;
+ vari.val.intval = n;
return vari.val;
}
- private static Term mul_set (Domain domain, Term[] args)
+ private static Term Fsub (Domain domain, Variable vari, Term[] args)
{
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
-
- for (int i = 1; i < args.Length; i++)
- n *= (int) args[i];
- vari.val = n;
- return vari.val;
- }
+ int n, i;
- private static Term sub_set (Domain domain, Term[] args)
- {
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
-
- for (int i = 1; i < args.Length; i++)
- n -= (int) args[i];
- vari.val = n;
+ if (vari == null)
+ {
+ n = args[0].Intval;
+ i = 1;
+ }
+ else
+ {
+ n = vari.val.Intval;
+ i = 0;
+ }
+ while (i < args.Length)
+ n -= (int) args[i++];
+ if (vari == null)
+ return n;
+ vari.val.intval = n;
return vari.val;
}
- private static Term div_set (Domain domain, Term[] args)
+ private static Term Fdiv (Domain domain, Variable vari, Term[] args)
{
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
+ int n, i;
- for (int i = 1; i < args.Length; i++)
- n /= (int) args[i];
- vari.val = n;
+ if (vari == null)
+ {
+ n = args[0].Intval;
+ i = 1;
+ }
+ else
+ {
+ n = vari.val.Intval;
+ i = 0;
+ }
+ while (i < args.Length)
+ n /= args[i++].Intval;
+ if (vari == null)
+ return n;
+ vari.val.intval = n;
return vari.val;
}
- private static Term mod_set (Domain domain, Term[] args)
+ private static Term Fmod (Domain domain, Variable vari, Term[] args)
{
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
-
- for (int i = 1; i < args.Length; i++)
- n %= (int) args[i];
- vari.val = n;
+ if (vari == null)
+ return (args[0].Intval % args[1].Intval);
+ vari.val.intval = vari.val.Intval % args[0].Intval;
return vari.val;
}
- private static Term logior_set (Domain domain, Term[] args)
+ private static Term Flogior (Domain domain, Variable vari, Term[] args)
{
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
-
- for (int i = 1; i < args.Length; i++)
- n |= (int) args[i];
- vari.val = n;
+ int n = vari == null ? 0 : vari.val.Intval;
+ foreach (Term arg in args)
+ n |= (int) arg;
+ if (vari == null)
+ return n;
+ vari.val.intval = n;
return vari.val;
}
- private static Term logand_set (Domain domain, Term[] args)
+ private static Term Flogand (Domain domain, Variable vari, Term[] args)
{
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
+ int n, i;
- for (int i = 1; i < args.Length; i++)
- n &= (int) args[i];
- vari.val = n;
+ if (vari == null)
+ {
+ n = args[0].Intval;
+ i = 1;
+ }
+ else
+ {
+ n = vari.val.Intval;
+ i = 0;
+ }
+ while (i < args.Length)
+ n &= (int) args[i++];
+ if (vari == null)
+ return n;
+ vari.val.intval = n;
return vari.val;
}
- private static Term lsh (Domain domain, Term[] args)
- {
- return (int) args[0] << (int) args[1];
- }
-
- private static Term lsh_set (Domain domain, Term[] args)
+ private static Term Flsh (Domain domain, Variable vari, Term[] args)
{
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
-
- n <<= (int) args[1];
- vari.val = n;
+ if (vari == null)
+ return args[0].Intval << args[1].Intval;
+ vari.val.intval = vari.val.Intval << args[0].Intval;
return vari.val;
}
- private static Term rsh (Domain domain, Term[] args)
+ private static Term Frsh (Domain domain, Variable vari, Term[] args)
{
- return (int) args[0] >> (int) args[1];
- }
-
- private static Term rsh_set (Domain domain, Term[] args)
- {
- Variable vari = domain.GetVar ((Name) args[0]);
- int n = (int) vari.val;
-
- n >>= (int) args[1];
- vari.val = n;
+ if (vari == null)
+ return args[0].Intval >> args[1].Intval;
+ vari.val.intval = vari.val.Intval >> args[0].Intval;
return vari.val;
}
- private static Term eq (Domain domain, Term[] args)
+ private static Term Feq (Domain domain, Variable vari, Term[] args)
{
Term o = args[0];
return One;
}
- private static Term noteq (Domain domain, Term[] args)
+ private static Term Fnoteq (Domain domain, Variable vari, Term[] args)
{
- return eq (domain, args);
+ return Feq (domain, vari, args);
}
- private static Term less_than (Domain domain, Term[] args)
+ private static Term Flt (Domain domain, Variable vari, Term[] args)
{
int n = (int) args[0];
return One;
}
- private static Term less_eq (Domain domain, Term[] args)
+ private static Term Fle (Domain domain, Variable vari, Term[] args)
{
int n = (int) args[0];
for (int i = 1; i < args.Length; i++)
return One;
}
- private static Term greater_than (Domain domain, Term[] args)
+ private static Term Fgt (Domain domain, Variable vari, Term[] args)
{
int n = (int) args[0];
for (int i = 1; i < args.Length; i++)
return One;
}
- private static Term greater_eq (Domain domain, Term[] args)
+ private static Term Fge (Domain domain, Variable vari, Term[] args)
{
int n = (int) args[0];
for (int i = 1; i < args.Length; i++)
return One;
}
- private static Term append (Domain domain, Term[] args)
+ private static Term Fappend (Domain domain, Variable vari, Term[] args)
{
- List<Term> list = new List<Term> ();
- Term result;
+ List<Term> list;
+
+ if (vari == null)
+ list = new List<Term> ();
+ else
+ list = vari.val.Listval;
foreach (Term arg in args)
{
else
list.Add (arg);
}
- result.intval = 0;
- result.objval = list;
- return result;
+ if (vari == null)
+ {
+ Term result;
+ result.intval = 0;
+ result.objval = list;
+ return result;
+ }
+ return vari.val;
}
- private static Term concat (Domain domain, Term[] args)
+ private static Term Fconcat (Domain domain, Variable vari, Term[] args)
{
- string str = "";
- Term result;
+ string str;
+
+ if (vari == null)
+ str = "";
+ else
+ str = vari.val.Strval;
foreach (Term arg in args)
{
else
str += (char) arg.Intval;
}
- result.intval = 0;
- result.objval = str;
- return result;
+ if (vari == null)
+ {
+ Term result;
+ result.intval = 0;
+ result.objval = str;
+ return result;
+ }
+ vari.val.objval = str;
+ return vari.val;
}
- private static Term nth (Domain domain, Term[] args)
+ private static Term Fnth (Domain domain, Variable vari, Term[] args)
{
Term result;
return result;
}
- private static Term copy (Domain domain, Term[] args)
+ private static Term Fcopy (Domain domain, Variable vari, Term[] args)
{
Term result;
return result;
}
- private static Term ins (Domain domain, Term[] args)
+ private static Term Fins (Domain domain, Variable vari, Term[] args)
{
- if (args[0].IsStr)
- {
- string str = args[0].Strval.Insert (args[1].Intval, args[2].Strval);
- args[0].objval = str;
- }
- else if (args[0].IsList)
- {
- args[0].Listval.InsertRange (args[1].Intval, args[2].Listval);
- }
+ if (vari.val.IsStr)
+ vari.val.objval
+ = vari.val.Strval.Insert (args[0].Intval, args[1].Strval);
+ else if (vari.val.IsList)
+ vari.val.Listval.InsertRange (args[0].Intval, args[1].Listval);
else
- throw new Exception ("term is not collection: " + args[0]);
- return args[0];
+ throw new Exception ("term is not collection: " + vari.val);
+ return vari.val;
}
-
- private static Term del (Domain domain, Term[] args)
+ private static Term Fdel (Domain domain, Variable vari, Term[] args)
{
- if (args[0].IsStr)
- {
- string str = args[0].Strval.Remove (args[1].Intval,
- args[2].Intval - args[1].Intval);
- args[0].objval = str;
- }
- else if (args[0].IsList)
- {
- args[0].Listval.RemoveRange (args[1].Intval,
- args[2].Intval - args[1].Intval);
- }
+ if (vari.val.IsStr)
+ vari.val.objval
+ = vari.val.Strval.Remove (args[0].Intval,
+ args[1].Intval - args[0].Intval);
+
+ else if (vari.val.IsList)
+ vari.val.Listval.RemoveRange (args[0].Intval,
+ args[1].Intval - args[0].Intval);
else
- throw new Exception ("term is not collection: " + args[0]);
- return args[0];
+ throw new Exception ("term is not collection: " + vari.val);
+ return vari.val;
}
- private static Term quote_clause (Domain domain, Term[] args)
+ private static Term Fand (Domain domain, Variable vari, Term[] args)
{
- return new Term (args[0]);
+ foreach (Term arg in args)
+ if (! arg.Eval (domain).IsTrue)
+ return Zero;
+ return One;
}
- private static Term eval_clause (Domain domain, Term[] args)
+ private static Term For (Domain domain, Variable vari, Term[] args)
+ {
+ foreach (Term arg in args)
+ if (arg.Eval (domain).IsTrue)
+ return One;
+ return Zero;
+ }
+
+ private static Term Feval (Domain domain, Variable vari, Term[] args)
{
return (args[0].Eval (domain));
}
- private static Term progn_clause (Domain domain, Term[] args)
+ private static Term Fprogn (Domain domain, Variable vari, Term[] args)
{
Term result = One;
return result;
}
- private static Term if_clause (Domain domain, Term[] args)
+ private static Term Fif (Domain domain, Variable vari, Term[] args)
{
if (args[0].Eval (domain).IsTrue)
return args[1].Eval (domain);
return args[2].Eval (domain);
}
- private static Term when_clause (Domain domain, Term[] args)
+ private static Term Fwhen (Domain domain, Variable vari, Term[] args)
{
if (! args[0].Eval (domain).IsTrue)
return Zero;
return result;
}
- private static Term while_clause (Domain domain, Term[] args)
+ private static Term Freturn (Domain domain, Variable vari, Term[] args)
{
- while (args[0].Eval (domain).IsTrue)
- for (int i = 1; i < args.Length; i++)
- args[i].Eval (domain);
- return Zero;
+ domain.ThrowReturn ();
+ return args.Length == 0 ? Zero : args[0];
+ }
+
+ private static Term Fbreak (Domain domain, Variable vari, Term[] args)
+ {
+ domain.ThrowBreak ();
+ return args.Length == 0 ? Zero : args[0];
+ }
+
+ private static Term Floop (Domain domain, Variable vari, Term[] args)
+ {
+ Term result = Zero;
+ try {
+ domain.Catch (CatchTag.Break);
+ while (! domain.Thrown)
+ foreach (Term arg in args)
+ {
+ result = arg.Eval (domain);
+ if (domain.Thrown)
+ return result;
+ }
+ } finally {
+ domain.Uncatch ();
+ }
+ return result;
+ }
+
+ private static Term Fwhile (Domain domain, Variable vari, Term[] args)
+ {
+ Term result = Zero;
+ try {
+ domain.Catch (CatchTag.Break);
+ while (! domain.Thrown && args[0].Eval (domain).IsTrue)
+ for (int i = 1; i < args.Length; i++)
+ {
+ result = args[i].Eval (domain);
+ if (domain.Thrown)
+ return result;
+ }
+ } finally {
+ domain.Uncatch ();
+ }
+ return result;
}
- private static Term cond_clause (Domain domain, Term[] args)
+ private static Term Fcond (Domain domain, Variable vari, Term[] args)
{
foreach (Term arg in args)
{
return Zero;
}
- private static Term foreach_clause (Domain domain, Term[] args)
+ private static Term Fforeach (Domain domain, Variable vari,
+ Term[] args)
{
- Variable vari = domain.GetVar ((Name) args[0]);
- List<Term> list = args[1].Listval;
+ Term result = args[0].Eval (domain);
+ if (domain.Thrown)
+ return result;
+ List<Term> list = result.Listval;
Bindings current = domain.bindings;
- foreach (Term term in list)
- {
- domain.Bind (vari, term);
- try {
- for (int i = 2; i < args.Length; i++)
- args[i].Eval (domain);
- } finally {
- domain.UnboundTo (current);
+ try {
+ domain.Catch (CatchTag.Break);
+ foreach (Term term in list)
+ {
+ domain.Bind (vari, term);
+ try {
+ for (int i = 1; i < args.Length; i++)
+ {
+ result = args[i].Eval (domain);
+ if (domain.Thrown)
+ return result;
+ }
+ } finally {
+ domain.UnboundTo (current);
+ }
}
- }
- return Zero;
+ } finally {
+ domain.Uncatch ();
+ }
+ return result;
+ }
+
+ private static Term Fquote (Domain domain, Variable vari, Term[] args)
+ {
+ return new Term (args[0]);
+ }
+
+ private static Term Ftype (Domain domain, Variable vari, Term[] args)
+ {
+ if (args[0].IsInt)
+ return TermInt;
+ if (args[0].IsStr)
+ return TermStr;
+ if (args[0].IsName)
+ return TermName;
+ if (args[0].IsList)
+ return TermList;
+ return TermTerm;
+ }
+
+ public static Term Fcatch (Domain domain, Variable vari, Term[] args)
+ {
+ Term result = Zero;
+ try {
+ domain.Catch (new CatchTag (args[0].Nameval));
+ result = args[1].Eval (domain);
+ } finally {
+ domain.Uncatch ();
+ }
+ return result;
}
+ public static Term Fthrow (Domain domain, Variable vari, Term[] args)
+ {
+ domain.ThrowTag (new CatchTag (args[0].Nameval));
+ return (args.Length == 1 ? Zero : args[1]);
+ }
+
+ public class TermValue
+ {
+ public virtual Term Eval (Domain domain) { return new Term (this); }
+ }
+
+ private class Funcall : TermValue
+ {
+ internal Function func;
+ internal Variable vari;
+ internal Term[] args;
+
+ public Funcall (XmlNode node, Domain domain)
+ {
+ vari = null;
+ Name name = node.Name;
+
+ if (name == Nfuncall)
+ name = node.Attributes[0].Value;
+ else if (node.Attributes[Nvname] != null)
+ vari = domain.GetVar (node.Attributes[Nvname].Value, true);
+ func = domain.GetFunc (name);
+ XmlNodeList nlist = node.ChildNodes;
+ int nargs = nlist.Count;
+
+ if (nargs < func.min_arg
+ || (func.max_arg >= 0 && nargs > func.max_arg))
+ throw new Exception ("Invalid number of arguments to: "
+ + name + " " + nargs);
+ args = new Term[nargs];
+ for (int i = 0; i < nlist.Count; i++)
+ args[i] = new Term (nlist[i], domain);
+ }
+
+ public Funcall (Domain domain, Name fname, Term[] args)
+ {
+ func = domain.GetFunc (fname);
+ this.args = args;
+ }
+
+ public Funcall (Domain domain, Name fname, Name vname, Term[] args)
+ {
+ func = domain.GetFunc (fname);
+ vari = domain.GetVar (vname, true);
+ this.args = args;
+ }
+
+ public override Term Eval (Domain domain)
+ {
+ domain.DebugWrite (true, "(({0}", func.name);
+ for (int i = 0; i < args.Length; i++)
+ domain.DebugWrite (false, " {0}", args[i].ToString ());
+ domain.DebugWrite (false, ")");
+ domain.depth++;
+ Term result = func.Call (domain, vari, args);
+ domain.depth--;
+ domain.DebugWrite (true, " ==> {0})", result.ToString ());
+ return result;
+ }
+
+ public override string ToString ()
+ {
+ string str = "<funcall fname=\"" + func.name;
+ if (args == null)
+ return str + "\"/>";
+ str += "\">";
+ foreach (Term e in args)
+ str += e;
+ return (str + "</funcall>");
+ }
+ }
public struct Term
{
public Term (Name name) { intval = 0; objval = name; }
public Term (string str) { intval = 0; objval = str; }
public Term (List<Term> list) { intval = 0; objval = list; }
- public Term (Term term) { intval = 0; objval = term; }
+ public Term (Term term) { intval = term.intval; objval = term.objval; }
+ public Term (TermValue obj) { intval = 0; objval = obj; }
public Term (XmlNode node, Domain domain)
{
objval = (Name) node.InnerText;
else if (name == Nstring)
objval = node.InnerText.Clone ();
- else if (name == Nvariable)
- objval = domain.GetVar ((Name) node.Attributes[0].Value);
+ else if (name == Nvarref)
+ objval = domain.GetVar ((Name) node.Attributes[0].Value, true);
else if (name == Nlist)
{
List<Term> list = new List<Term> ();
objval = list;
}
else
- {
- if (name == Nfuncall)
- name = node.Attributes[0].Value;
-
- Function func = domain.GetFunc (name);
- XmlNodeList nlist = node.ChildNodes;
- int nargs = nlist.Count;
-
- if (nargs < func.min_arg
- || (func.max_arg >= 0 && nargs > func.max_arg))
- throw new Exception ("Invalid number of arguments to: "
- + name + " " + nargs);
- Term[] args = new Term[nargs];
- for (int i = 0; i < nlist.Count; i++)
- args[i] = new Term (nlist[i], domain);
- objval = new Funcall (func, args);
- }
+ objval = new Funcall (node, domain);
}
}
- private class Funcall
- {
- internal Function func;
- internal Term[] args;
-
- public Funcall (Function func, Term[] args)
- {
- this.func = func;
- this.args = args;
- }
-
- public Term Eval (Domain domain)
- {
- domain.DebugWrite (true, "(({0}", func.name);
- for (int i = 0; i < args.Length; i++)
- domain.DebugWrite (false, " {0}", args[i].ToString ());
- domain.DebugWrite (false, ")");
- domain.depth++;
- Term result = func.Call (domain, args);
- domain.depth--;
- domain.DebugWrite (true, " ==> {0})", result.ToString ());
- return result;
- }
-
- public override string ToString ()
- {
- string str = "<funcall fname=\"" + func.name;
- if (args == null)
- return str + "\"/>";
- str += "\">";
- foreach (Term e in args)
- str += e;
- return (str + "</funcall>");
+ public object Objval {
+ get {
+ if (objval == null)
+ throw new Exception ("term is an integer: " + this);
+ return objval;
}
}
}
}
+ public string Nameval {
+ get {
+ if (! IsName)
+ throw new Exception ("term is not symbol: " + this);
+ return (Name) objval;
+ }
+ }
+
public List<Term> Listval {
get {
if (! IsList)
}
public bool IsInt { get { return (objval == null); } }
public bool IsStr { get { return (objval is string); } }
+ public bool IsName { get { return (objval is Name); } }
public bool IsList { get { return (objval is List<Term>); } }
+ public bool IsType (Type type)
+ {
+ return (objval == null ? type == typeof (int)
+ : type == objval.GetType ());
+ }
+
public Term Eval (Domain domain)
{
if (objval == null || objval is Name || objval is string)
return this;
if (objval is List<Term>)
return new Term ((List<Term>) objval);
- if (objval is Funcall)
- return ((Funcall) objval).Eval (domain);
- if (objval is Variable)
- return ((Variable) objval).val;
- if (objval is Term)
- return (Term) objval;
+ if (objval is TermValue)
+ return ((TermValue) objval).Eval (domain);
throw new Exception ("invalid Term object: " + objval);
}
}
}
- static Term Zero = new Term (0);
- static Term One = new Term (1);
+ static private Term Zero = new Term (0);
+ static private Term One = new Term (1);
+ static private Term TermInt = new Term (Ninteger);
+ static private Term TermStr = new Term (Nstring);
+ static private Term TermName = new Term (Nsymbol);
+ static private Term TermList = new Term (Nlist);
+ static private Term TermTerm = new Term ((Name) "term");
internal static int parse_integer (string str)
{
int c = str[0];
int i;
- if (c == '0' && str[1] == 'x')
+ if (c == '?')
+ return str[1];
+ if ((c == '0' || c == '#') && str[1] == 'x')
{
i = 0;
for (int idx = 2; idx < len; idx++)
private Term[] terms;
- public Xexpression (string url, Domain domain)
+ private void parse_terms (Domain domain, XmlNode node)
{
- XmlDocument doc = new XmlDocument (Name.Table);
- XmlNode node;
-
- using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
- {
- do {
- reader.Read ();
- } while (reader.NodeType != XmlNodeType.None
- && (reader.NodeType != XmlNodeType.Element
- || reader.Name != Nexpr));
- if (reader.NodeType == XmlNodeType.None)
- throw new Exception ("Node <expr> not found");
- node = doc.ReadNode (reader);
- }
-
int nterms = 0;
- for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
+ for (XmlNode n = node; n != null; n = n.NextSibling)
if (n.NodeType == XmlNodeType.Element)
{
if (n.Name == Ndefun)
terms = new Term[nterms];
int i = 0;
- for (XmlNode n = node.FirstChild; n != null; n = n.NextSibling)
+ for (XmlNode n = node; n != null; n = n.NextSibling)
if (n.NodeType == XmlNodeType.Element)
{
if (n.Name == Ndefun)
}
}
+ public Xexpression (Domain domain, XmlNode node)
+ {
+ parse_terms (domain, node);
+ }
+
+ public Xexpression (Domain domain, string url)
+ {
+ XmlDocument doc = new XmlDocument (Name.Table);
+ XmlNode node;
+
+ using (XmlTextReader reader = new XmlTextReader (url, Name.Table))
+ {
+ do {
+ reader.Read ();
+ } while (reader.NodeType != XmlNodeType.None
+ && (reader.NodeType != XmlNodeType.Element
+ || reader.Name != Nexpr));
+ if (reader.NodeType == XmlNodeType.None)
+ throw new Exception ("Node <expr> not found");
+ node = doc.ReadNode (reader);
+ }
+ parse_terms (domain, node.FirstChild);
+ }
+
public Term Eval (Domain domain)
{
Term result = Zero;
domain.depth = 0;
- foreach (Term term in terms)
- result = term.Eval (domain);
+ try {
+ domain.Catch (CatchTag.Return);
+ foreach (Term term in terms)
+ {
+ result = term.Eval (domain);
+ if (domain.Thrown)
+ return result;
+ }
+ } finally {
+ domain.Uncatch ();
+ }
return result;
}