Programming

Undeclared entities in OPML outlines

OPML Link Publisher uses XOM, an XML processing library for Java that requires well-formed XML. Because of this, I've run into a problem: Radio and Frontier can author OPML files that contain undeclared entity references, which breaks the well-formedness rule. Based on my rudimentary understanding of this situation, any XML data that does not have a document type declaration (such as OPML) must declare entity references for any entity other than &amp, &apos, &gt, &lt, and ... (read more)

2003/06/06

Using OPML bookmarks in Mozilla and Netscape Navigator

I've released version 0.1 of OPML Link Publisher, a Java application that publishes an OPML link directory outline as a bookmarks.html file, which can be automatically loaded by Mozilla or Netscape Navigator and manually imported into Internet Explorer. I wrote the application because a Mozilla crash wiped out my bookmarks and I was tired of having bookmarks in several different browsers and other files. Radio UserLand's outliner can be used to create link directories (other outliners may ... (read more)

2003/06/03

MacBird wasn't built in a day

I'm trying to build MacBird, a process that's deterred considerably by my lack of Mac programming experience. Because UserLand's last release was built with CodeWarrior Pro 4, I've been using a Discover Programming edition of CodeWarrior 4 -- the closest I could find on eBay -- but it appears to lack the Power PC Linker specified as a build target. I'm guessing I need to upgrade to get more linkers, but until I know for sure, I don't want to spend more on this project than I already have. ... (read more)

2003/05/06

Now that I'm puttering around with XML-RPC and the Apache XML-RPC Java class library, the most common problem I encounter is XML that Apache's XML-RPC client can't parse (usually because of problems with the XML). On the radio-dev mailing list, Matt Croydon of PostNeo recommended a great Windows utility that can spy on XML-RPC, HTTP, and other networking operations: TCPTrace by Simon Fell. The program runs as a proxy server, passing requests to the right server and port, receiving the response, ... (read more)

2002/11/19

Object-Oriented Programming Pioneer Kristen Nygaard Dies

Kristen Nygaard, the computer science pioneer who is credited with Ole Johan-Dahl for the invention of inheritance, has died at age 75. Nygaard's website contains an encyclopedia entry he wrote about their role in early object-oriented programming, along with a lot of other interesting material on programming, including a funny article about the object-oriented family tree. "Ole-Johan Dahl and I are said to be the 'fathers' of SIMULA I and SIMULA 67 and thus of object-oriented programming," ... (read more)

2002/08/12