XQueryをためす

こちら（XQuery Example）を参考に．

  NSXMLDocument* document= [NSXMLNode document];
  [document setVersion:@"1.0"];
  [document setCharacterEncoding:@"ISO-8859-1"];
  
  NSXMLElement* bookstore= [NSXMLNode elementWithName:@"bookstore"];
  [document setRootElement:bookstore];
  {
   NSXMLElement* book= [NSXMLNode elementWithName:@"book"];
   [bookstore addChild:book];
   [book addAttribute:[NSXMLNode attributeWithName:@"category" 
            stringValue:@"COOKING"]];
   {
    NSXMLElement* title= [NSXMLNode elementWithName:@"title"];
    [book addChild:title];
    [title addAttribute:[NSXMLNode attributeWithName:@"lang" 
              stringValue:@"en"]];
    [title addChild:[NSXMLNode textWithStringValue:@"Everyday Italian"]];
   }
   {
    NSXMLElement* author= [NSXMLNode elementWithName:@"author"];
    [book addChild:author];
    [author addChild:[NSXMLNode textWithStringValue:@"Giada De Laurentiis"]];
   }
   {
    NSXMLElement* year= [NSXMLNode elementWithName:@"year"];
    [book addChild:year];
    [year addChild:[NSXMLNode textWithStringValue:@"2005"]];
   }
   {
    NSXMLElement* price= [NSXMLNode elementWithName:@"price"];
    [book addChild:price];
    [price addChild:[NSXMLNode textWithStringValue:@"30.00"]];
   }
  }
  {
   NSXMLElement* book= [NSXMLNode elementWithName:@"book"];
   [bookstore addChild:book];
   [book addAttribute:[NSXMLNode attributeWithName:@"category" 
            stringValue:@"CHILDREN"]];
   {
    NSXMLElement* title= [NSXMLNode elementWithName:@"title"];
    [book addChild:title];
    [title addAttribute:[NSXMLNode attributeWithName:@"lang" 
              stringValue:@"en"]];
    [title addChild:[NSXMLNode textWithStringValue:@"Harry Potter"]];
   }
   {
    NSXMLElement* author= [NSXMLNode elementWithName:@"author"];
    [book addChild:author];
    [author addChild:[NSXMLNode textWithStringValue:@"J K. Rowling"]];
   }
   {
    NSXMLElement* year= [NSXMLNode elementWithName:@"year"];
    [book addChild:year];
    [year addChild:[NSXMLNode textWithStringValue:@"2005"]];
   }
   {
    NSXMLElement* price= [NSXMLNode elementWithName:@"price"];
    [book addChild:price];
    [price addChild:[NSXMLNode textWithStringValue:@"29.99"]];
   }
  }
  {
   NSXMLElement* book= [NSXMLNode elementWithName:@"book"];
   [bookstore addChild:book];
   [book addAttribute:[NSXMLNode attributeWithName:@"category" 
            stringValue:@"WEB"]];
   {
    NSXMLElement* title= [NSXMLNode elementWithName:@"title"];
    [book addChild:title];
    [title addAttribute:[NSXMLNode attributeWithName:@"lang" 
              stringValue:@"en"]];
    [title addChild:[NSXMLNode textWithStringValue:@"XQuery Kick Start"]];
   }
   {
    NSXMLElement* author= [NSXMLNode elementWithName:@"author"];
    [book addChild:author];
    [author addChild:[NSXMLNode textWithStringValue:@"James McGovern"]];
   }
   {
    NSXMLElement* author= [NSXMLNode elementWithName:@"author"];
    [book addChild:author];
    [author addChild:[NSXMLNode textWithStringValue:@"Per Bothner"]];
   }
   {
    NSXMLElement* author= [NSXMLNode elementWithName:@"author"];
    [book addChild:author];
    [author addChild:[NSXMLNode textWithStringValue:@"Kurt Cagle"]];
   }
   {
    NSXMLElement* author= [NSXMLNode elementWithName:@"author"];
    [book addChild:author];
    [author addChild:[NSXMLNode textWithStringValue:@"James Linn"]];
   }
   {
    NSXMLElement* author= [NSXMLNode elementWithName:@"author"];
    [book addChild:author];
    [author addChild:[NSXMLNode textWithStringValue:@"Vaidyanathan Nagarajan"]];
   }
   {
    NSXMLElement* year= [NSXMLNode elementWithName:@"year"];
    [book addChild:year];
    [year addChild:[NSXMLNode textWithStringValue:@"2003"]];
   }
   {
    NSXMLElement* price= [NSXMLNode elementWithName:@"price"];
    [book addChild:price];
    [price addChild:[NSXMLNode textWithStringValue:@"49.99"]];
   }
  }
  {
   NSXMLElement* book= [NSXMLNode elementWithName:@"book"];
   [bookstore addChild:book];
   [book addAttribute:[NSXMLNode attributeWithName:@"category" 
            stringValue:@"WEB"]];
   {
    NSXMLElement* title= [NSXMLNode elementWithName:@"title"];
    [book addChild:title];
    [title addAttribute:[NSXMLNode attributeWithName:@"lang" 
              stringValue:@"en"]];
    [title addChild:[NSXMLNode textWithStringValue:@"Learning XML"]];
   }
   {
    NSXMLElement* author= [NSXMLNode elementWithName:@"author"];
    [book addChild:author];
    [author addChild:[NSXMLNode textWithStringValue:@"Erik T. Ray"]];
   }
   {
    NSXMLElement* year= [NSXMLNode elementWithName:@"year"];
    [book addChild:year];
    [year addChild:[NSXMLNode textWithStringValue:@"2003"]];
   }
   {
    NSXMLElement* price= [NSXMLNode elementWithName:@"price"];
    [book addChild:price];
    [price addChild:[NSXMLNode textWithStringValue:@"39.95"]];
   }
  }
  
  NSString* output= [document XMLStringWithOptions:(NSXMLNodePrettyPrint|NSXMLNodeCompactEmptyElement)];
  NSLog(@"%@", output);
  
  NSArray *nodes= [bookstore objectsForXQuery:@"/bookstore/book[price<30]" error:NULL];
  NSLog(@"%d", [nodes count]);
  int i;
  for(i= 0;i<[nodes count];i++) {
   NSLog(@"%@", [[nodes objectAtIndex:i] XMLString]);
  }

結果

> <?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
    <book category="COOKING">
        <title lang="en">Everyday Italian</title>
        <author>Giada De Laurentiis</author>
        <year>2005</year>
        <price>30.00</price>
    </book>
    <book category="CHILDREN">
        <title lang="en">Harry Potter</title>
        <author>J K. Rowling</author>
        <year>2005</year>
        <price>29.99</price>
    </book>
    <book category="WEB">
        <title lang="en">XQuery Kick Start</title>
        <author>James McGovern</author>
        <author>Per Bothner</author>
        <author>Kurt Cagle</author>
        <author>James Linn</author>
        <author>Vaidyanathan Nagarajan</author>
        <year>2003</year>
        <price>49.99</price>
    </book>
    <book category="WEB">
        <title lang="en">Learning XML</title>
        <author>Erik T. Ray</author>
        <year>2003</year>
        <price>39.95</price>
    </book>
</bookstore>
> 1
> <book category="CHILDREN"><title lang="en">Harry Potter</title><author>J K. Rowling</author><year>2005</year><price>29.99</price></book>

これだけだとXPathと差がないな．