I had some time today, so I built a little AJAX application for this blog. It’s an expression calculator. The world really doesn’t need another one, but it was the easiest thing that includes ANTLR for building a lexer/parser/AST and the Google Web Toolkit for building the client. Why? Because it’s fun …
Geometry for kids
2007-02-10 – 15:10
One of our girls visits the 7th grade (13 years, secondary school) right now. In geometry, they are talking about the congruence rules for triangles and triangles in general. Yesterday’s homework included a geometrical problem: construct the space diagonal of a cube geometrically and specify its length (side length of the cube is 5.3cm).
While this might be an easy problem for grownups, it seemed not so easy for her. She drew a grid model of the cube, connected the opposite vertices, and measured off the length of the resulting diagonal. It seem logical and right for her. When I asked her about the actual angles in a cube, and how they relate to her projection, it became quite clear, that some angles in the drawing weren’t quite what they should have been.
Creating a WordPress Plugin
2007-02-10 – 13:40
It wasn’t planned that way, but it turned out that I had to write a WordPress plugin myself to solve a problem. I want to have a Google Web Toolkit application run inside my blog. No big deal, but I couldn’t accomplish one tiny detail. GWT applications need a meta tag with the name gwt:module in the page header section. How do I manage to get this meta tag up there whenever a post includes a GWT application?
Programming editors
2007-02-01 – 22:20
Everybody who is programming is using one or more of them. My favorite programming editor is Epsilon from Lugaru Software Ltd., and that since 1996. It’s around since 1984. Although my first version was for DOS, Windows, and OS/2, I used it primarily under DOS for writing C programs. I started in 1978 with a BASIC dialect and 8080/Z80 assembler on a SORD M200 computer. I wasn’t thinking about what editor to use back then, because there was no choice. I had to use the one that came with this SORD computer. A little later I switched to C and then C++, followed by Java in 1996. There will be something after Java, but I can’t see it yet. It’s not so much the programming language itself that keeps me, but the Java platform.
Problem with Oracle
2007-01-28 – 16:25
While operating synformation together with an Oracle database (prior to version 10g), the following error can occur during page compilation:
FATAL ERROR IN TWO-TASK SERVER: error = 12571 ksedmp: internal or fatal error
This error is logged by Oracle in the user dump trace files. After this error has occurred, no more pages can be compiled. From the ACU client software, it looks like the system is locked up. Only a restart of the synformation server software will help temporarily.