// Copyright (c) 2002, 2003, 2006  Per M.A. Bothner.// This is free software;  for terms and warranty disclaimer see ./COPYING.package gnu.xquery.util;import gnu.mapping.*;import gnu.lists.*;import gnu.math.Numeric;import gnu.math.RealNum;import gnu.kawa.xml.UntypedAtomic;import gnu.expr.*;import gnu.bytecode.Type;import gnu.kawa.xml.XDataType;import gnu.xquery.lang.XQuery;public class BooleanValue extends Procedure1 implements CanInline{  public static final BooleanValue booleanValue =    new BooleanValue("boolean-value");  public BooleanValue (String name)  {    super(name);  }  public static boolean booleanValue(Object value)  {    if (value instanceof Boolean)      return ((Boolean) value).booleanValue();    if (value instanceof Number        && (value instanceof RealNum || ! (value instanceof Numeric)))      {        double d = ((Number) value).doubleValue();        return d != 0 && ! Double.isNaN(d);      }    if (value instanceof SeqPosition)      return true;    if (value instanceof String        || value instanceof gnu.text.Path        || value instanceof UntypedAtomic)      return value.toString().length() > 0;    if (value instanceof Values)      {	Values values = (Values) value;	Object value1 = values.getPosNext(0);	if (value1 == Sequence.eofValue)	  return false;	int next = values.nextDataIndex(0);	if (next < 0)	  return booleanValue(value1);        if (value1 instanceof SeqPosition)          return true;      }    throw new WrongType("fn:boolean", 1, value, "boolean-convertible-value");  }  public static boolean not(Object value)  {    return ! booleanValue(value);  }  public Object apply1(Object arg)  {    return booleanValue(arg) ? Boolean.TRUE : Boolean.FALSE;  }  public Expression inline (ApplyExp exp, ExpWalker walker)  {    Expression[] args = exp.getArgs();    if (args.length == 1)      {        Expression arg = args[0];        Type type = arg.getType();        if (type == XDataType.booleanType)          return arg;        if (type == null)          exp.setType(XDataType.booleanType);        if (arg instanceof QuoteExp)          {            Object value = ((QuoteExp) arg).getValue();            try              {                return booleanValue(value) ? XQuery.trueExp : XQuery.falseExp;              }            catch (Throwable ex)              {                String message = "cannot convert to a boolean";                walker.getMessages().error('e', message);                return new ErrorExp(message);              }          }      }    return exp;  }}