[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: SAX: do we want a base class (was Re: SAX: towards a solution)
James Clark wrote [03:33 PM 1/3/98 ]: >David Ornstein wrote: > >> >I am also assuming that we will provide not only a callback interface, >> >but also an (optional) base class with stub methods that implementors >> >can override as needed; that means that novice users will not have to >> >implement all of SAX, even if we do end up with nine or ten methods. >> >> This worries me. My interest is in implementations of SAX-clients in C++. >> Will I have, as part of somebody's SAX implementation that I'm using, this >> (optional) base class available to me too? > >In C++ I can't see any need for a base class separate from the >interface. You can just have a single class which provides empty >definitions for all virtual functions. If the only purpose for the base class is to provide *empty* definitions for the functions, then I agree. On the other hand, I'm seeing the base class fill up with a variety of "default implementations" for many of the functions in the interface. These "default implementations" will be non-empty and their behavior may turn out to be expected by clients. As a result, reasonable implementations will probably need/want to provide the base class. This may well end up meaning that the "default implementations" actually become a part of the SAX "spec". Witness your comment in a previous note: >If we do this, then the stub (adapter) class should do > >void ignorableWhitespace(char ch[], int off, int count) { > charData(ch, off, count); >} > >This means that users who don't care about the difference can just >ignore it. David ================================ David Ornstein Pragmatica, Inc. http://www.pragmaticainc.com xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
|
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|