Schizoid Classes, Rodney Bates
Smalltalk-80 was an important and enlightening experiment in just how far object-orientation can be taken in a programming language. It is simple, compact, and shows a rare and refreshing integrity of concept. To accomplish its goals, it introduces the idea that the variables of a class can be either class variables or instance variables, and the methods can be either class methods or instance methods. This turns the class into a mixture of two fundamentally different conceptsâ€”type and moduleâ€”with very different semantics. Smalltalk manages to do this relatively cleanly.
The author is of the opinion that [t]he best-designed languages give you two abstraction toolsâ€”a module and an object typeâ€”each of which serves its own purpose reasonably well - I wonder if he is thinking about Smalltalk or about Ada...
Seems prime material here for Lambda.
Mind as well complete the daily trifecta and post the article on Programming Language Popularity. The author combines search, advertizing and job data to try and draw a measurement on various aspects of popularity. Open to criticism, but the results are somewhat non-surprising given the weights applied, and coming up with a truly objective measurement is probably impossible.
The text for Smalltalk-80, Bits of History, Words of Advice is now available online. The text documents the development history of the Smalltalk 80 language.
Probably goes against Dijkstra's advice of modeling real world objects, but Luca Cardelli is exploring Programming Languages for Biology.
Fresh O'Caml is Mark Shinwell's sucessor to Andrew Pitts's last summer's blockbuster FreshML. It's experimental, but Tom tells me it's very cool, and I trust him. This work comes out of... no, not INRIA, enclave of O'Caml High Acolytes, but rather the University of Cambridge Computer Laboratory Theory and Semantics Group. Here are the obligatory tasty paper morsels:
More papers than you can shake a stick at on Fresh O'Caml's dad, FreshML, are also available.
A nice application of category theory to computer science that is rather simpler than its application to semantics tends to get is the single and double pushout approach to graph transformation. Categorical pushouts allow patterns and rewrites on many kinds of structure, in particular graphs, to be specified in a simple manner. The theory can be read forwards, generalising term rewriting systems to graph rewriting systems, or backwards, specifying parsing problems for a graph grammar.
There's a shortage of good introductory material to this idea online. Offline I can recommend Tutorial introduction to the algebraic approach of graph grammars based on double and single pushouts [citeseer]. Online I suggest Practical Use of Graph Rewriting, and I welcome other suggestions.
We are on holiday (it's the Jewish new year), and on top of that there are some problems at work, that may mean looking for a new job soon.
Hence my lack of posts.
I am sure others will fill in.
I had been breathlessly watching Paul Graham's website hoping for news about Arc, his "New Lisp". But I hadn't realized that a group of developers had already beaten him to the punch!
newLisp is an updated (and scaled down) Lisp, targeted at the scripting world. From the web site:
newLISP is a general purpose scripting language for developing Web applications and programs in general and in the domain of Artificial Intelligence (AI) and statistics.
Among its many interesting features (such as useful functions for getting scripting work done, good performance, and small footprint) are:
While many new scripting languages languish with good implementations, but no fully-realized libraries or interaction with outside software, newLisp seems to have sprung fully-formed, with various useful libraries already implemented.
Newlisp compiles on most LINUX, UNIX versions, CYGWIN, Windows, and presumably Mac OS X. It is licensed under the GNU Public License, GPL
Who knows -- perhaps now Ehud will have a Lisp with which he can finally get some scripting work done!
Active forum topics
New forum topics