Thursday, February 05, 2009

I'm trying to read some code in Objective-C. This is hard, but it's solidifying my abstract understanding of programming languages. I'm not that hardcore a programmer, but I guess I've picked up a few things over the years (gawd that makes me sound old).

One of the neat things about Objective-C is that using a class or instance method involves sending a message. C++, in contrast, calls those methods. A C++ object has a fixed number of methods that can knowably be called. An Objective-C object might be able to handle arbitrary messages. This makes some things harder and somethings easier: polymorphism is easier; finding cases of using the wrong type of object or having a null object are harder to detect (must be done at runtime, not compile time).

The thing is, this is very familiar to me because this is how wire protocols work. In fact Objective-C has "protocols" which are interfaces, or a set of messages, that an object claims to be able to handle, so the terminology overlaps quite a bit. Anyway, in a wire protocol the client sends a message, and because anything can happen to that message, the client has to be able to handle a large number of outcomes. Polymorphism? You bet; a server that appears to be a HTTP server (implements the HTTP protocol) can also be a WebDAV server, a CalDAV server and an FTP server.

Designing protocols can be hard for people who think in terms of fixed interfaces à la C++. RPC-style protocols embody this thinking, making Remote Procedure Calls and expecting predictable, limited results. It makes more sense to me now, that RPC-style protocols are so brittle: designers and implementors are acting as if there's compile-time checking of the remote interface, whereas since the remote interface is on somebody else's computer that may have been upgraded or may just have a different implementation, of course there's no compile-time checking.

Sunday, February 01, 2009

Mommy blogging today: Natasha said I should post about toddler sleeping stuff.

I have a kid that naps and goes to bed willingly and easily. Clearly there is a huge part of sheer luck in this because I've seen little correlation between loving, wise, firm parents and perfect kids, and I'm not always wise and firm. But we did luck out on a few things that have added to his personality to make for the easiest bedtimes ever.
  1. We introduced an attachment toy early on. This toy, known here as "sleepy bear" because his eyes appear closed, is a blanket-with-head style minky toy.
  2. We taught the sign for bear early on (bear hug yourself with arms crossed, and scratch your upper arms with each opposite hand) so he could ask for the toy pre-speech.
  3. We attached a pacifier to sleepy bear with a folded strip of fabric. The fabric loop goes through the pacifier loop and around the pacifier, so it can come off for easy machine laundering of the toy.
  4. We bought a second identical sleepy bear (and attached another fabric loop) when it became clear this was the favourite toy. Usually one remains hidden to be brought out very conveniently when there's contamination events or simply the bear has gotten too dirty from grubby hands.
  5. Since sleepy bear is always "sleepy", he has to stay in the kid's bedroom most of the time. We make exceptions for when he's sick or at difficult times like coming home in the car after bedtime.
So now, when we say "It's bedtime" his response is (whining) "Nooooo...." but the next phase is "Let's go find sleepy bear" and he responds "OK" and follows us to the bedroom. Sleepy bear is closely associated with sleeping and triggers him to lie down and relax.

He is too young to say recognize fatigue and say "I'm tired, I'm ready for a little nap" but he's easily old enough to ask for bear. If we're at home and his hands are clean, we ask him to go into his bedroom and cuddle with bear until he's ready to come out without bear (and if he comes out with bear we bring him back to the bedroom and ask him to say bye to bear before he can go out and play again). So yesterday morning he did this and actually fell asleep, getting a bonus morning nap which he doesn't usually need any more.

When we want him to fall asleep in a new place (traveling or spending an evening at friends') we just bring sleepy bear. We pull out the toy and any old blanket, and that's enough for the kid to sleep in a new room fairly easily.

Finally, this somewhat limits pacifier use without ruling it out entirely. I don't care too deeply, but there's something annoying about a kid that talks through a pacifier all the time. Having the main pacifier attached to a toy limited to the bedroom means that most of the time when he's playing he doesn't have one. We do have a couple extras on leashes for carseat or stroller travel where it appears to seriously improve patience levels.

I don't mean to give advice because all parents are different and all kids are different, but I did agree it was worth explaining how this works for us. Good luck!

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