g__ | 14 years ago | on: A Gentle Introduction to Category Theory [pdf]
Functor typeclass in Haskell models category-theoretic endofunctor rather well.
g__'s comments
g__ | 15 years ago | on: Ask HN: What is a monad?
DON'T start functional programming with monads. Familiarize with currying, pattern matching, how to create data types in Haskell, using recursion instead of loops, higher order functions, list comprehensions, type classes, polymorphism in Haskell (different than subtyping in OOP). Ignore monads for a while. To understand monads you must have a good grip of those concepts. You can start with http://learnyouahaskell.com/chapters.
You'll see Haskell tutorials delay telling about the concept. There's a reason.
For a bird's eye of monads you can check this: http://www.reddit.com/r/programming/comments/64th1/monads_in...
If you are ready, read and do exercises in http://blog.sigfpe.com/2007/04/trivial-monad.html and then http://blog.sigfpe.com/2006/08/you-could-have-invented-monad....
g__ | 15 years ago | on: Google update on China
What does the following mean, on http://www.google.cn/landing/cnexp/indexd.html?
我们已移至 google.com.hk
请收藏我们的新网址
g__ | 15 years ago | on: A Haskell webserver ...
GHC 6.6 is almost 4 years old, please upgrade. (http://hackage.haskell.org/platform/)
g__ | 16 years ago | on: S4 - $12 for 1 year of 1 TB write-only storage
And it's extremely fast:
$ pv /dev/zero > /dev/null
18.6GB 0:00:05 [3.76GB/s] [ <=> ]g__ | 16 years ago | on: Haskell: Pure and Lazy, yet Functional
Iterators sometimes require restructuring, as in
http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
In Haskell they don't - you might write this "producer-consumer" composing a function that produces a stream with a function that consumes a stream. How would you approach that problem in C++?
g__ | 16 years ago | on: Donald Knuth making an Earthshaking Announcement June 30 in San Francisco
Under assumption P=NP, a polynomial algorithm is already known (!): http://en.wikipedia.org/wiki/P_%3D_NP_problem#Polynomial-tim...
The problem is: will humanity find a feasible algorithm?
g__ | 16 years ago | on: Good read: cPython's dictionary implementation
g__ | 16 years ago | on: 9,73,241,561,1081,1849,_?_
You'd have to determine if a program halts. Unless you restrict to non-Turing-complete language, this is undecidable.
g__ | 16 years ago | on: 9,73,241,561,1081,1849,_?_
This answer is also correct in another way :)
http://threesixty360.wordpress.com/2008/04/30/1-2-4-8-what-c...
g__ | 16 years ago | on: I am a former executive of a large famous company in the computer industry. AMA
I Was also an Illegal E-Mail Spammer for 5 Years. I got Caught. AMA
g__ | 16 years ago | on: Layman's Guide to the Banach-Tarski Paradox
Simple version of B-T in 1D:
http://www.math.ucla.edu/~tao/resource/general/121.1.00s/tar...
g__ | 16 years ago | on: Haskell Sudoku solver
and $ map can be shortened to all in many places.
I'd use pointless style more: row = (!!)
The function valid has a lot of repetition, maybe the repeating part can be abstracted of?
Instead of length possible > 0, you can use not $ null possible. This is faster, since it doesn't go through the whole list.
Instead of pattern matching on Maybe (tile), you can use Prelude's maybe.
g__ | 16 years ago | on: ACM 20 Most Influential Papers on Programming Languages [tarball]
Another nice collection:
http://www.reddit.com/r/programming/comments/9220o/ask_progg...
g__ | 16 years ago | on: UK Postal Code Data leaked
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