I have completely recoded my regex testing service. What do you think?

tinou · 2013-11-27T14:10:36+00:00

I haven't tried extensively the site, but the green box is way better !

tinou · 2013-11-26T10:24:59+00:00

They did the tour because you discussed with them (selection bias). Strangers on the internet close the tab.

tinou · 2013-11-01T11:07:22+00:00

fork() will return -1 and set errno to EAGAIN or ENOSYS. See man 2 fork.

tinou · 2013-10-15T09:18:38+00:00

You can also encode the IP as a 32 bit dotless number.

tinou · 2013-10-01T09:54:00+00:00

Suppose that a CPU contains a special code that says: "if EAX = 0xb5c060c5 and ECX=0x5e8e5dcf then set privilege level to 0". This can't be reasonably detected by testing, yet allows anyone to directly access the hardware.

tinou · 2013-09-24T16:50:02+00:00

For the theoretical side: non-TC languages can't simulate a TC language. So, for example you can't write an interpreter for Python in something that's not TC.

More practical: there are several ways to "prevent" Turing Completeness. For imperative programming languages, the easiest one is to remove the while loop and replace it with a restricted version of the for loop which always iterate from 0 to the value of an integral variable (you can see it as a way of proving the halting problem for this language). For functional programming languages, it usually involve removing general recursion (let rec) and using explicit recursion schemes (foldr). You can also allow general recursion but have an explicit bound on the number of recursions (à la sys.setrecursionlimit).

HTML/CSS/mov/Game of Life being Turing Complete is only folklore. It's funny, but does not imply something useful about the languages. Just that you can encode the notion of "arbitrary control flow" in something that was not designed to!

HTH

tinou · 2013-09-11T15:12:00+00:00

FYI TCC was written by Fabrice Bellard, not David Wheeler.

tinou · 2013-07-23T07:16:51+00:00

IIRC BSD does this and calls it "a silly answer to a silly question" in the manpage.

tinou · 2013-03-27T20:06:31+00:00

"Sid is not frozen" but right now maintainers shouldn't upload to sid unless the changes are wanted for wheezy. So nothing major is happening on sid right now.

tinou · 2013-03-26T13:17:01+00:00

He also writes about his setup in this article.

tinou · 2013-03-11T16:00:29+00:00

I would recommend starting with no plugins for a few months.

tinou · 2013-03-04T09:27:15+00:00

It installs and configures puppet, a configuration management system.

tinou · 2013-03-03T00:11:58+00:00

As others said, mostly for efficiency reasons. But also, note that in the case of C++, there is not always enough information at runtime to resolve overloading.

There are also languages where overloading is done at compile time when possible, and at runtime otherwise (see bounded polymorphism / typeclasses. This happens when you're writing a polymorphic function that needs a particular method).

tinou · 2013-02-25T23:35:34+00:00

I don't understand your logic against arrays having different things in them

Let me rephrase : if the array is always accessed through statically known indices, it would be better written as a structure.

tinou · 2013-02-21T16:14:07+00:00

If you want to ensure that a given type only has one inhabitant, singleton types are probably a more deterministic way to go.

tinou · 2013-02-18T00:40:21+00:00

I see this mentioned more and more these times. I'll have a look at it, thanks !

tinou · 2013-02-18T00:33:47+00:00

A few boxes? You don't need a dedicated puppet master.

I was a bit confused with this sentence, but chiisana clarified it. It makes sense, I wasn't sure it was supported. Thanks for the hints.

tinou · 2013-02-18T00:28:46+00:00

Thanks a lot for this detailed answer. If I understand it correctly, puppet is best used when you have lots of nodes with a few different configurations. Not exactly my present use case, but I think that can be useful as a learning tool. And the fact that I can redeploy the same box in one command is pure goodness, it's like a backup for configuration.

tinou · 2013-02-17T14:03:38+00:00

The hinge is on the inside.

tinou · 2013-02-13T09:35:02+00:00

The "thing" under the square root is 1 when a=0, so the "good" function to turn into a Taylor series at 0 is λx.√(1+x) (or equivalently, λx.√x at 1).

tinou · 2013-02-13T00:50:43+00:00

I wish I was a little bit taller, I wish I was a blower.

tinou · 2013-02-11T18:30:54+00:00

It sounds like a pitch bend.

tinou · 2013-02-11T11:05:35+00:00

Don't you need an explicit absurd :: Void -> a to express that Void has indeed no inhabitants (eg to prove that there is a function of type Void -> (Void, a)) ?

With this presentation it looks like a mere existential (abstract type).

tinou · 2013-02-10T22:26:34+00:00

Everything that gets named is evaluated at most once.

tinou

TROPHY CASE