Ejemplo n.º 1
0
        public virtual IokeObject ConvertToText(IokeObject self, IokeObject m, IokeObject context, bool signalCondition)
        {
            if (signalCondition)
            {
                IokeObject condition = IokeObject.As(IokeObject.GetCellChain(context.runtime.Condition,
                                                                             m,
                                                                             context,
                                                                             "Error",
                                                                             "Type",
                                                                             "IncorrectType"), context).Mimic(m, context);
                condition.SetCell("message", m);
                condition.SetCell("context", context);
                condition.SetCell("receiver", self);
                condition.SetCell("expectedType", context.runtime.GetSymbol("Text"));

                object[] newCell = new object[] { self };

                context.runtime.WithRestartReturningArguments(() => { context.runtime.ErrorCondition(condition); },
                                                              context,
                                                              new IokeObject.UseValue("text", newCell));
                return(IokeObject.ConvertToText(newCell[0], m, context, signalCondition));
            }
            return(null);
        }
Ejemplo n.º 2
0
        public int GetEvaluatedArguments(IokeObject context, IokeObject message, object on, IList argumentsWithoutKeywords, IDictionary <string, object> givenKeywords)
        {
            Runtime runtime   = context.runtime;
            IList   arguments = message.Arguments;
            int     argCount  = 0;

            foreach (object o in arguments)
            {
                if (Message.IsKeyword(o))
                {
                    givenKeywords[IokeObject.As(o, context).Name] = Interpreter.GetEvaluatedArgument(((Message)IokeObject.dataOf(o)).next, context);
                }
                else if (Message.HasName(o, "*") && IokeObject.As(o, context).Arguments.Count == 1)    // Splat
                {
                    object result = Interpreter.GetEvaluatedArgument(IokeObject.As(o, context).Arguments[0], context);
                    if (IokeObject.dataOf(result) is IokeList)
                    {
                        IList elements = IokeList.GetList(result);
                        foreach (object ox in elements)
                        {
                            argumentsWithoutKeywords.Add(ox);
                        }
                        argCount += elements.Count;
                    }
                    else if (IokeObject.dataOf(result) is Dict)
                    {
                        IDictionary keys = Dict.GetMap(result);
                        foreach (DictionaryEntry me in keys)
                        {
                            givenKeywords[Text.GetText(IokeObject.ConvertToText(me.Key, message, context, true)) + ":"] = me.Value;
                        }
                    }
                    else if (IokeObject.FindCell((IokeObject)result, "asTuple") != runtime.nul)
                    {
                        object   tupledValue = Interpreter.Send(runtime.asTuple, context, result);
                        object[] values      = Tuple.GetElements(tupledValue);
                        foreach (object val in values)
                        {
                            argumentsWithoutKeywords.Add(val);
                        }
                        argCount += values.Length;
                    }
                    else
                    {
                        IokeObject condition = IokeObject.As(IokeObject.GetCellChain(runtime.Condition,
                                                                                     message,
                                                                                     context,
                                                                                     "Error",
                                                                                     "Invocation",
                                                                                     "NotSpreadable"), context).Mimic(message, context);
                        condition.SetCell("message", message);
                        condition.SetCell("context", context);
                        condition.SetCell("receiver", on);
                        condition.SetCell("given", result);

                        IList outp = IokeList.GetList(runtime.WithRestartReturningArguments(() => { runtime.ErrorCondition(condition); },
                                                                                            context,
                                                                                            new Restart.DefaultValuesGivingRestart("ignoreArgument", runtime.nil, 0),
                                                                                            new Restart.DefaultValuesGivingRestart("takeArgumentAsIs", IokeObject.As(result, context), 1)
                                                                                            ));

                        foreach (object ox in outp)
                        {
                            argumentsWithoutKeywords.Add(ox);
                        }
                        argCount += outp.Count;
                    }
                }
                else
                {
                    var xx = Interpreter.GetEvaluatedArgument(o, context);
                    argumentsWithoutKeywords.Add(xx);
                    argCount++;
                }
            }

            while (argCount < min || (max != -1 && argCount > max))
            {
                int finalArgCount = argCount;
                if (argCount < min)
                {
                    IokeObject condition = IokeObject.As(IokeObject.GetCellChain(runtime.Condition,
                                                                                 message,
                                                                                 context,
                                                                                 "Error",
                                                                                 "Invocation",
                                                                                 "TooFewArguments"), context).Mimic(message, context);
                    condition.SetCell("message", message);
                    condition.SetCell("context", context);
                    condition.SetCell("receiver", on);
                    condition.SetCell("missing", runtime.NewNumber(min - argCount));

                    IList newArguments = IokeList.GetList(runtime.WithRestartReturningArguments(() => { runtime.ErrorCondition(condition); },
                                                                                                context,
                                                                                                new NewArgumentGivingRestart("provideExtraArguments"),
                                                                                                new Restart.DefaultValuesGivingRestart("substituteNilArguments", runtime.nil, min - argCount)));

                    foreach (object ox in newArguments)
                    {
                        argumentsWithoutKeywords.Add(ox);
                    }
                    argCount += newArguments.Count;
                }
                else
                {
                    IokeObject condition = IokeObject.As(IokeObject.GetCellChain(runtime.Condition,
                                                                                 message,
                                                                                 context,
                                                                                 "Error",
                                                                                 "Invocation",
                                                                                 "TooManyArguments"), context).Mimic(message, context);
                    condition.SetCell("message", message);
                    condition.SetCell("context", context);
                    condition.SetCell("receiver", on);
                    condition.SetCell("extra", runtime.NewList(ArrayList.Adapter(argumentsWithoutKeywords).GetRange(max, finalArgCount - max)));

                    runtime.WithReturningRestart("ignoreExtraArguments", context, () => { runtime.ErrorCondition(condition); });
                    argCount = max;
                }
            }

            var intersection = new SaneHashSet <string>(givenKeywords.Keys);

            foreach (string k in keywords)
            {
                intersection.Remove(k);
            }

            if (krest == null && intersection.Count > 0)
            {
                IokeObject condition = IokeObject.As(IokeObject.GetCellChain(runtime.Condition,
                                                                             message,
                                                                             context,
                                                                             "Error",
                                                                             "Invocation",
                                                                             "MismatchedKeywords"), context).Mimic(message, context);
                condition.SetCell("message", message);
                condition.SetCell("context", context);
                condition.SetCell("receiver", on);

                IList expected = new SaneArrayList();
                foreach (string s in keywords)
                {
                    expected.Add(runtime.NewText(s));
                }

                condition.SetCell("expected", runtime.NewList(expected));

                IList extra = new SaneArrayList();
                foreach (string s in intersection)
                {
                    extra.Add(runtime.NewText(s));
                }
                condition.SetCell("extra", runtime.NewList(extra));
                runtime.WithReturningRestart("ignoreExtraKeywords", context, () => { runtime.ErrorCondition(condition); });
            }

            return(argCount);
        }
Ejemplo n.º 3
0
        public static void Init(IokeObject obj)
        {
            Runtime runtime = obj.runtime;

            obj.Kind = "DefaultBehavior Internal";

            obj.RegisterMethod(runtime.NewNativeMethod("expects one 'strange' argument. creates a new instance of Text with the given Java String backing it.",
                                                       new NativeMethod("internal:createText",
                                                                        DefaultArgumentsDefinition
                                                                        .builder()
                                                                        .WithRequiredPositionalUnevaluated("text")
                                                                        .Arguments,
                                                                        (method, context, message, on, outer) => {
                outer.ArgumentsDefinition.CheckArgumentCount(context, message, on);
                object o   = Message.GetArguments(message)[0];
                bool cache = true;
                if (o is IokeObject)
                {
                    cache = false;
                    o     = Interpreter.GetEvaluatedArgument(o, context);
                }
                if (o is string)
                {
                    string s     = (string)o;
                    object value = runtime.NewText(new StringUtils().ReplaceEscapes(s));
                    if (cache)
                    {
                        Message.CacheValue(message, value);
                    }
                    return(value);
                }
                else
                {
                    return(IokeObject.ConvertToText(o, message, context, true));
                }
            })));

            obj.RegisterMethod(runtime.NewNativeMethod("expects one 'strange' argument. creates a new instance of Number that represents the number found in the strange argument.",
                                                       new NativeMethod("internal:createNumber",
                                                                        DefaultArgumentsDefinition
                                                                        .builder()
                                                                        .WithRequiredPositionalUnevaluated("number")
                                                                        .Arguments,
                                                                        (method, context, message, on, outer) => {
                outer.ArgumentsDefinition.CheckArgumentCount(context, message, on);
                object o   = Message.GetArguments(message)[0];
                bool cache = true;

                if (o is IokeObject)
                {
                    cache = false;
                    o     = Interpreter.GetEvaluatedArgument(o, context);
                }
                object value = null;
                if (o is string)
                {
                    value = runtime.NewNumber((string)o);
                }
                else if (o is int)
                {
                    value = runtime.NewNumber((int)o);
                }

                if (cache)
                {
                    Message.CacheValue(message, value);
                }
                return(value);
            })));

            obj.RegisterMethod(runtime.NewNativeMethod("takes zero or more arguments, calls asText on non-text arguments, and then concatenates them and returns the result.",
                                                       new NativeMethod("internal:concatenateText", DefaultArgumentsDefinition.builder()
                                                                        .WithRest("textSegments")
                                                                        .Arguments,
                                                                        (method, context, message, on, outer) => {
                var args = new SaneArrayList();
                outer.ArgumentsDefinition.GetEvaluatedArguments(context, message, on, args, new SaneDictionary <string, object>());

                StringBuilder sb = new StringBuilder();

                foreach (object o in args)
                {
                    if (o is IokeObject)
                    {
                        if (IokeObject.dataOf(o) is Text)
                        {
                            sb.Append(Text.GetText(o));
                        }
                        else
                        {
                            var aa = Interpreter.Send(context.runtime.asText, context, o);
                            sb.Append(Text.GetText(aa));
                        }
                    }
                    else
                    {
                        sb.Append(o);
                    }
                }

                return(context.runtime.NewText(sb.ToString()));
            })));

            obj.RegisterMethod(runtime.NewNativeMethod("takes one or more arguments. it expects the last argument to be a text of flags, while the rest of the arguments are either texts or regexps or nil. if text, it will be inserted verbatim into the result regexp. if regexp it will be inserted into a group that make sure the flags of the regexp is preserved. if nil, nothing will be inserted.",
                                                       new NativeMethod("internal:compositeRegexp", DefaultArgumentsDefinition.builder()
                                                                        .WithRest("regexpSegments")
                                                                        .Arguments,
                                                                        (method, context, message, on, outer) => {
                var args = new SaneArrayList();
                outer.ArgumentsDefinition.GetEvaluatedArguments(context, message, on, args, new SaneDictionary <string, object>());

                StringBuilder sb = new StringBuilder();
                if ((IokeObject.dataOf(on) is Text) || (IokeObject.dataOf(on) is Regexp))
                {
                    AddObject(on, sb, context);
                }

                int size = args.Count;

                foreach (object o in ArrayList.Adapter(args).GetRange(0, size - 1))
                {
                    AddObject(o, sb, context);
                }

                object f     = args[size - 1];
                string flags = null;
                if (f is string)
                {
                    flags = (string)f;
                }
                else if (IokeObject.dataOf(f) is Text)
                {
                    flags = Text.GetText(f);
                }
                else if (IokeObject.dataOf(f) is Regexp)
                {
                    sb.Append(Regexp.GetPattern(f));
                    flags = Regexp.GetFlags(f);
                }

                return(context.runtime.NewRegexp(sb.ToString(), flags, context, message));
            })));

            obj.RegisterMethod(runtime.NewNativeMethod("expects two 'strange' arguments. creates a new mimic of Regexp with the given Java String backing it.",
                                                       new NativeMethod("internal:createRegexp", DefaultArgumentsDefinition.builder()
                                                                        .WithRequiredPositionalUnevaluated("regexp")
                                                                        .WithRequiredPositionalUnevaluated("flags")
                                                                        .Arguments,
                                                                        (method, context, message, on, outer) => {
                outer.ArgumentsDefinition.CheckArgumentCount(context, message, on);
                object o  = Message.GetArguments(message)[0];
                object o2 = Message.GetArguments(message)[1];
                if (o is IokeObject)
                {
                    o = Interpreter.GetEvaluatedArgument(o, context);
                }
                if (o2 is IokeObject)
                {
                    o2 = Interpreter.GetEvaluatedArgument(o2, context);
                }
                if (o is string)
                {
                    string s = (string)o;
                    return(runtime.NewRegexp(new StringUtils().ReplaceRegexpEscapes(s), (string)o2, context, message));
                }
                else
                {
                    return(IokeObject.ConvertToRegexp(o, message, context));
                }
            })));

            obj.RegisterMethod(runtime.NewNativeMethod("expects one 'strange' argument. creates a new instance of Decimal that represents the number found in the strange argument.",
                                                       new NativeMethod("internal:createDecimal", DefaultArgumentsDefinition.builder()
                                                                        .WithRequiredPositionalUnevaluated("decimal")
                                                                        .Arguments,
                                                                        (method, context, message, on, outer) => {
                outer.ArgumentsDefinition.CheckArgumentCount(context, message, on);
                object o   = Message.GetArguments(message)[0];
                bool cache = true;
                if (o is IokeObject)
                {
                    cache = false;
                    o     = Interpreter.GetEvaluatedArgument(o, context);
                }
                object value = runtime.NewDecimal((string)o);
                if (cache)
                {
                    Message.CacheValue(message, value);
                }
                return(value);
            })));
        }
Ejemplo n.º 4
0
Archivo: Text.cs Proyecto: tspring/ioke
        public override void Init(IokeObject obj)
        {
            Runtime runtime = obj.runtime;

            obj.Kind = "Text";
            obj.Mimics(IokeObject.As(IokeObject.FindCell(runtime.Mixins, "Comparing"), null), runtime.nul, runtime.nul);

            obj.RegisterMethod(runtime.NewNativeMethod("returns a hash for the text",
                                                       new NativeMethod.WithNoArguments("hash", (method, context, message, on, outer) => {
                outer.ArgumentsDefinition.CheckArgumentCount(context, message, on);
                return(context.runtime.NewNumber(((Text)IokeObject.dataOf(on)).text.GetHashCode()));
            })));

            obj.RegisterMethod(runtime.NewNativeMethod("returns true if the left hand side text is equal to the right hand side text.",
                                                       new TypeCheckingNativeMethod("==", TypeCheckingArgumentsDefinition.builder()
                                                                                    .ReceiverMustMimic(runtime.Text)
                                                                                    .WithRequiredPositional("other")
                                                                                    .Arguments,
                                                                                    (method, on, args, keywords, context, message) => {
                Text d       = (Text)IokeObject.dataOf(on);
                object other = args[0];

                return(((other is IokeObject) &&
                        (IokeObject.dataOf(other) is Text) &&
                        ((on == context.runtime.Text || other == context.runtime.Text) ? on == other :
                         d.text.Equals(((Text)IokeObject.dataOf(other)).text))) ? context.runtime.True : context.runtime.False);
            })));

            obj.RegisterMethod(runtime.NewNativeMethod("Returns a text representation of the object",
                                                       new NativeMethod.WithNoArguments("asText",
                                                                                        (method, context, message, on, outer) => {
                outer.ArgumentsDefinition.GetEvaluatedArguments(context, message, on, new SaneArrayList(), new SaneDictionary <string, object>());
                return(on);
            })));

            obj.RegisterMethod(runtime.NewNativeMethod("Takes any number of arguments, and expects the text receiver to contain format specifications. The currently supported specifications are only %s and %{, %}. These have several parameters that can be used. See the spec for more info about these. The format method will return a new text based on the content of the receiver, and the arguments given.",
                                                       new TypeCheckingNativeMethod("format", TypeCheckingArgumentsDefinition.builder()
                                                                                    .ReceiverMustMimic(obj)
                                                                                    .WithRest("replacements")
                                                                                    .Arguments,
                                                                                    (self, on, args, keywords, context, message) => {
                StringBuilder result = new StringBuilder();
                Format(on, message, context, args, result);
                return(context.runtime.NewText(result.ToString()));
            })));


            obj.RegisterMethod(obj.runtime.NewNativeMethod("Converts the content of this text into a rational value",
                                                           new TypeCheckingNativeMethod.WithNoArguments("toRational", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(Text.ToRational(on, context, message));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Converts the content of this text into a decimal value",
                                                           new TypeCheckingNativeMethod.WithNoArguments("toDecimal", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(Text.ToDecimal(on, context, message));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns a text inspection of the object",
                                                           new TypeCheckingNativeMethod.WithNoArguments("inspect", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(self.runtime.NewText(Text.GetInspect(on)));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns a brief text inspection of the object",
                                                           new TypeCheckingNativeMethod.WithNoArguments("notice", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(self.runtime.NewText(Text.GetInspect(on)));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns a text where all non-safe characters have been replaced with safe ones",
                                                           new TypeCheckingNativeMethod.WithNoArguments("makeXMLSafe", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(self.runtime.NewText(new StringUtils().XmlSafe(Text.GetText(on))));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns a lower case version of this text",
                                                           new TypeCheckingNativeMethod.WithNoArguments("lower", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(self.runtime.NewText(Text.GetText(on).ToLower()));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns an upper case version of this text",
                                                           new TypeCheckingNativeMethod.WithNoArguments("upper", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(self.runtime.NewText(Text.GetText(on).ToUpper()));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns a version of this text with leading and trailing whitespace removed",
                                                           new TypeCheckingNativeMethod.WithNoArguments("trim", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(self.runtime.NewText(Text.GetText(on).Trim()));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns an array of texts split around the argument",
                                                           new TypeCheckingNativeMethod("split", TypeCheckingArgumentsDefinition.builder()
                                                                                        .ReceiverMustMimic(obj)
                                                                                        .WithOptionalPositional("splitAround", "")
                                                                                        .Arguments,
                                                                                        (self, on, args, keywords, context, message) => {
                string real = Text.GetText(on);
                var r       = new SaneArrayList();
                Pattern p   = null;

                if (args.Count == 0)
                {
                    p = new Pattern("\\s");
                }
                else
                {
                    object arg = args[0];
                    if (IokeObject.dataOf(arg) is Regexp)
                    {
                        p = Regexp.GetRegexp(arg);
                    }
                    else
                    {
                        string around = Text.GetText(arg);
                        p             = new Pattern(Pattern.Quote(around));
                    }
                }

                RETokenizer tok  = new RETokenizer(p, real);
                tok.EmptyEnabled = false;
                while (tok.HasMore)
                {
                    r.Add(context.runtime.NewText(tok.NextToken));
                }

                return(context.runtime.NewList(r));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Takes two text arguments where the first is the substring to replace, and the second is the replacement to insert. Will only replace the first match, if any is found, and return a new Text with the result.",
                                                           new TypeCheckingNativeMethod("replace", TypeCheckingArgumentsDefinition.builder()
                                                                                        .ReceiverMustMimic(obj)
                                                                                        .WithRequiredPositional("pattern")
                                                                                        .WithRequiredPositional("replacement")
                                                                                        .Arguments,
                                                                                        (self, on, args, keywords, context, message) => {
                string initial = Text.GetText(on);
                string repl    = Text.GetText(args[1]);

                object arg = args[0];

                Pattern pat = null;
                if (IokeObject.dataOf(arg) is Regexp)
                {
                    pat = Regexp.GetRegexp(arg);
                }
                else
                {
                    string around = Text.GetText(arg);
                    pat           = new Pattern(Pattern.Quote(around));
                }

                Replacer r    = pat.Replacer(repl);
                string result = r.ReplaceFirst(initial);

                return(context.runtime.NewText(result));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Takes two text arguments where the first is the substring to replace, and the second is the replacement to insert. Will replace all matches, if any is found, and return a new Text with the result.",
                                                           new TypeCheckingNativeMethod("replaceAll", TypeCheckingArgumentsDefinition.builder()
                                                                                        .ReceiverMustMimic(obj)
                                                                                        .WithRequiredPositional("pattern")
                                                                                        .WithRequiredPositional("replacement")
                                                                                        .Arguments,
                                                                                        (self, on, args, keywords, context, message) => {
                string initial = Text.GetText(on);
                string repl    = Text.GetText(args[1]);

                object arg = args[0];

                Pattern pat = null;
                if (IokeObject.dataOf(arg) is Regexp)
                {
                    pat = Regexp.GetRegexp(arg);
                }
                else
                {
                    string around = Text.GetText(arg);
                    pat           = new Pattern(Pattern.Quote(around));
                }

                Replacer r    = pat.Replacer(repl);
                String result = r.Replace(initial);

                return(context.runtime.NewText(result));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns the length of this text",
                                                           new TypeCheckingNativeMethod.WithNoArguments("length", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(context.runtime.NewNumber(GetText(on).Length));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("compares this text against the argument, returning -1, 0 or 1 based on which one is lexically larger",
                                                           new TypeCheckingNativeMethod("<=>", TypeCheckingArgumentsDefinition.builder()
                                                                                        .ReceiverMustMimic(obj)
                                                                                        .WithRequiredPositional("other")
                                                                                        .Arguments,
                                                                                        (self, on, args, keywords, context, message) => {
                object arg = args[0];

                if (!(IokeObject.dataOf(arg) is Text))
                {
                    arg = IokeObject.ConvertToText(arg, message, context, false);
                    if (!(IokeObject.dataOf(arg) is Text))
                    {
                        // Can't compare, so bail out
                        return(context.runtime.nil);
                    }
                }

                if (on == context.runtime.Text || arg == context.runtime.Text)
                {
                    if (on == arg)
                    {
                        return(context.runtime.NewNumber(0));
                    }
                    return(context.runtime.nil);
                }

                int result = string.CompareOrdinal(Text.GetText(on), Text.GetText(arg));
                if (result < 0)
                {
                    result = -1;
                }
                else if (result > 0)
                {
                    result = 1;
                }

                return(context.runtime.NewNumber(result));
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("takes one argument, that can be either an index or a range of two indicis. this slicing works the same as for Lists, so you can index from the end, both with the single index and with the range.",
                                                           new TypeCheckingNativeMethod("[]", TypeCheckingArgumentsDefinition.builder()
                                                                                        .ReceiverMustMimic(obj)
                                                                                        .WithRequiredPositional("index")
                                                                                        .Arguments,
                                                                                        (self, on, args, keywords, context, message) => {
                object arg    = args[0];
                IokeData data = IokeObject.dataOf(arg);

                if (data is Range)
                {
                    int first = Number.ExtractInt(Range.GetFrom(arg), message, context);

                    if (first < 0)
                    {
                        return(context.runtime.NewText(""));
                    }

                    int last       = Number.ExtractInt(Range.GetTo(arg), message, context);
                    bool inclusive = Range.IsInclusive(arg);

                    string str = GetText(on);
                    int size   = str.Length;

                    if (last < 0)
                    {
                        last = size + last;
                    }

                    if (last < 0)
                    {
                        return(context.runtime.NewText(""));
                    }

                    if (last >= size)
                    {
                        last = inclusive ? size - 1 : size;
                    }

                    if (first > last || (!inclusive && first == last))
                    {
                        return(context.runtime.NewText(""));
                    }

                    if (!inclusive)
                    {
                        last--;
                    }

                    return(context.runtime.NewText(str.Substring(first, (last + 1) - first)));
                }
                else if (data is Number)
                {
                    string str = GetText(on);
                    int len    = str.Length;

                    int ix = ((Number)data).AsNativeInteger();

                    if (ix < 0)
                    {
                        ix = len + ix;
                    }

                    if (ix >= 0 && ix < len)
                    {
                        return(context.runtime.NewNumber(str[ix]));
                    }
                    else
                    {
                        return(context.runtime.nil);
                    }
                }

                return(on);
            })));

            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns a symbol representing the Unicode category of the character",
                                                           new TypeCheckingNativeMethod.WithNoArguments("category", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                string character = GetText(on);
                if (character.Length == 1)
                {
                    return(context.runtime.GetSymbol(UnicodeBlock.Of(character[0])));
                }

                IokeObject condition = IokeObject.As(IokeObject.GetCellChain(runtime.Condition,
                                                                             message,
                                                                             context,
                                                                             "Error",
                                                                             "Default"), context).Mimic(message, context);
                condition.SetCell("message", message);
                condition.SetCell("context", context);
                condition.SetCell("receiver", on);
                condition.SetCell("text", context.runtime.NewText("Text does not contain exactly one character"));

                runtime.ErrorCondition(condition);
                return(null);
            })));
            obj.RegisterMethod(obj.runtime.NewNativeMethod("Returns a new text where all the escapes in the current text have been evaluated - exactly as if another parsing step had been applied. This does not evaluate embedded code, though.",
                                                           new TypeCheckingNativeMethod.WithNoArguments("evaluateEscapes", obj,
                                                                                                        (self, on, args, keywords, context, message) => {
                return(context.runtime.NewText(new StringUtils().ReplaceEscapes(GetText(on))));
            })));
        }