archives

A Visual Environment for Developing Context-Sensitive Term Rewriting Systems

(via an interesting discussion on the types list)

A Visual Environment for Developing Context-Sensitive Term Rewriting Systems. Matthews, Findler, Flatt, Felleisen. International Conference on Rewriting Techniques and Applications (RTA) 2004.

Over the past decade, researchers have found context-sensitive term-rewriting semantics to be powerful and expressive tools for modeling programming languages, particularly in establishing type soundness proofs. Unfortunately, developing such semantics is an error-prone activity. To address that problem, we have designed PLT Redex, an embedded domain-specific language that helps users interactively create and debug context-sensitive term-rewriting systems. We introduce the tool with a series of examples and discuss our experience using it in courses and developing an operational semantics for R5RS Scheme.

Seems like a nice tool (it's DrScheme based, of course). I guess I should try it out.

No asterisks, please

When a topic gets very lengthy, it can be difficult to find those items which are new. One solution is to click on the message in the chronological view, read that particular entry (only), hit the back button, chose the next, etc.

The first problem with this approach is that if I close my browser (perhaps accidentally) after reading the first item, I will lose the stars for all the rest of the unread items in the same topic, because they all show in the same page as far as the browser is concerned.

The second problem is that it requires me to constantly reload the page unnecessarily, wasting time and bandwidth.

There is a second solution, which is to search for asterisks in the text. This will quite handily find all the unread items on the page. Unfortunately, asterisks also appear in code, and *some* people *use* them for emphasis, instead of using the <em> tag. Ideally perhaps, we should just use a more distinctive search marker. In the meantime, it would be helpful if people would avoid using asterisks unnecessarily.

Thanks.