Tuesday  2002-10-29   Development

Standard SQL

Whatever merits SQL may have, portability is not one of them.

 
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Sunday  2002-08-11   Development

From JPEG to abstract algebra

A couple of demonstrations of modern functional programming by Jeroen Fokker:

"Functional Specification of the JPEG algorithm, and an Implementation for Free"

"Explaining Algebraic Theory with Functional Programs"

 
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Wednesday  2002-06-19   Development

Macromedia Blueprint Application Center : Pet Market.

From mesh on MX

Macromedia has released the Macromedia MX Pet Market Blueprint Application and Center. The Pet Market Blueprint application is an online store for a fictional pet retailer similar to the Java™ Pet Store released by Sun and the Microsoft .NET Pet Shop.

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Flash MX and its friends are riding high. After many years of disappointing remote UI aka browser or thin-client based applications, we may finally get halfway usable UI with Flash. Using HTTP as UI protocol should make hall of shame for misuse and abuse of protocols. Applets could have been successful if Sun had made Java a bit more high level language or delivered a useful 4GL/IDE from the beginning.
 
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Tuesday  2002-06-18   Development

JXPath - XPath for Java

From Jakarta page on JXPath:

JXPath applies XPath expressions to graphs of objects of all kinds: JavaBeans, Maps, Servlet contexts, DOM etc, including mixtures thereof.

Consider this example:

Address address = (Address)JXPathContext.newContext(vendor).
         getValue("locations[address/zipCode='90210']/address");

This XPath expression is equvalent to the following Java code:

Address address = null;
Collection locations = vendor.getLocations();
Iterator it = locations.iterator();
while (it.hasNext()){
    Location location = (Location)it.next();
    String zipCode = location.getAddress().getZipCode();
    if (zipCode.equals("90210")){
      address = location.getAddress();
      break;
    }
}

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Some pros and cons:
Pro: Code gets shorter.
Con: Compiler can't do type checking. Expression is just an embedded string.

Pro: Because it's string we can do dynamic queries via file system, telnet, http texts!
Con: Security.

Pro: Same expression/query language for Java and XML.
Con: Why mix oil and water?

Pro: XPath can be the universal query language.
Con: We live in an interesting time.

NB JXPath is a subset of Jex API.
 
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Monday  2002-05-13   Development

Reverse literate programming

Reverse literate programming by Markus Knasmüller (Johannes Kepler University Linz) shows how a dynamic environment can vastly simplify extraordinarily cumbersome literate programming by use of effective hypertext and outliners (folding editor).

 
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