Monday, April 27, 2009

Building Common Lisp library

I've talked about the negative impact of hackbraries in my previous blog http://tourdelisp.blogspot.com.It is time to take my own advise and build a lisp library myself. It was a long time ago since I wanted to make portable s-expression syntax prolog,covered with tests, that works out of the box on Windows,Linux at least over the major lisp implementations.Also I want to be modular in order to switch unification functionality if there is better one in the market such as Marco Antoniotti cl-unification And now its a good moment to do it. First I will Implement the algorithm described in Yet Another Efficient Unification Algorithm paper. Then I will start building the actual s-expression syntax prolog.
Suciu algorithm has two steps,parsing terms into unification table then unifying the terms using the table . Thanks to Maciej Katafiasz and Madhu I already had a functions for parsing the unification table, you can see them lisp paste . However both solutions lacked the way or returning the indices of p & q term that are needed in the next step so I wrote parsing unification table functionality from scratch. My solution is probably slower, but Its shorter and easier to understand.Then I've pack everything into asdf file and added another asdf file for the tests. I decided to go with cl-rt test framework since its simple and doesn't have any dependencies. If I need something more complex I'll check other testing frameworks later.
I have enough to cal it a project so lets apply for hosting at common-Lisp.net.

Thursday, April 23, 2009

Reasoned Schemer

I've ordered Reasoned Schemer and waiting for it to come, being in Macedonia it took other Amazon order (Let Over Lambda) nearly 3 months to arrive. I wonder why don't many authors of programming books offer electronic version for sale. They are more convenient to read and try the code plus they don't kill trees? Is it the fear of piracy. If somebody wants to pirate book, it will just scan it and post to internet. I really don't see any point.

Monday, April 6, 2009

lure and bait

I've just canceled my wireless internet contract with T-mobile after just 2 months. Beside the slow internet I got ten times larger bill for my first month for going over my bandwith limit. So I asked them to put a limiter whenever I pass the limit just turn me off, or warn me or whatever. But they just didn't wanted to do it. Instead I got a number to track on my own. So I decided to cancel my subscription. And got charged 6 month bills for doing that. I could think about the way management was thinking for squeezing every bit of money they can, and forgetting about those unimportant things called customer satisfaction. If they were honest and asked for more money up front and offered convenient way to track my spending I would be satisfied and they will earned much more. Now I feel cheated as in classic lure and bait situation. They robbed me but they actually robbed themselves.
I wonder if those penalties payed for canceling the service show up as negative marketing or they're profit as usual. And no matter how many commercials they run and what kind of sponsorship they won't get the money of anybody I know.
And they just have to piss off enough people. There is always a choice.

Announcement

There are more non-lisp things I want to write about and tourdelisp is lisp focused blog so I decided to move to a new place http://slobodanblazeski.blogspot.com/ . The old content will stay here but there will be no new updates.