An initial hurdle facing developers of these toolkits is the problem of loading source code. Javascript is loaded and executed natively in the browser environment, and it would be nice to load alternative language sources in a similar manner. So, today I wrote a library to do that.

The library, called LoadForCompile, is invoked with a MIME type and a callback. It searches the DOM for script elements with the given MIME type, loads their sources, and passes them to the callback. There is a very simple demo page with a "compiler" that displays whatever source code it is provided. Following is the documentation for the library.

Description

LoadForCompile will retrieve alternate-language source code and pass it (in order) to onLoad. Any sources that cannot be retrieved will be ignored by default.

If the onFinish argument is provided, it will be called when all sources have been loaded and passed.

If the onError argument is provided, it will be called with (src, k), where src is the offending URL and k is a continuation of the loading process, so the relying client may continue or entirely halt the loading process by calling k or not calling it, respectively.

Usage

1. Place script elements in your HTML document with desired MIME type.
2. Each script element may have a src attribute, an inline body between the opening and closing tags, or both. The body is guaranteed to be called immediately after the associated remote source, or not at all.
3. Finally, call LoadForCompile with the MIME type and callbacks.

Specification

LoadForCompile searches the DOM for any script nodes bearing the target MIME type. For each one, it records the src attribute and the contents of the text node, if any. It is an error to have non-text elements as children of the script node, and in such a situation the behavior of this library is unspecified.

The library uses asynchronous requests to load any remote resources specified by src attributes. This loading occurs in an unspecified order. If any remote source fails to load, the library will mark that source (and any associated inline body) as invalid. If onError is provided, it will be called with a continuation function that will resume progress. (If the continuation is not called, no additional callbacks will be made.)

Note that if onError is provided and does not call the continuation, onFinish will not be called.

Metadata

The library is in version 0.2 and is licensed under the LGPL.

I use xset, a command that can set various preferences in the current X display. One of the parameter sets is b, the properties of the system bell. It can be used to set the relative volume, pitch, and duration. Here's an example:

xset b 50 700 5

That example sets the system bell to 50% volume, a pitch of 700 hertz, and a duration of 5 milliseconds.

Experiment by entering that command, then pressing [Backspace] on the next line of your terminal (to generate a system bell.) Your hardware may not support certain combinations, in which the bell is silent.

To have this setting take effect every time you log in, add it to your session startup commands. In Ubuntu, that's System :: Preferences :: Sessions.

I was developing a GWT application with Eclipse and ran into a client-server communication issue that manifested at runtime. The client would request an object from the server, the object would properly serialize and deserialize (verified by JS debugger), and then GWT's glue code would throw IncompatibleRemoteServiceException (saying "This application is out of date, please click the refresh button on your browser.")

Ultimately, I believe this exception was occurring because either

1. the class in question extended java.util.EnumMap, a standard Java library class that GWT reimplements in JS, or
2. accessing Whatever.class is disallowed in GWT, but is required for generic code that deals with enumeration types.

When I rewrote the class to itself reimplement EnumMap (but specialized to a specific Enum), the exception disappeared. Read on for gory Java details:

EnumMap maps values of an Enum to values of some other type. In my case, I was mapping to Boolean values, creating a selection of the Enum. Ordinarily I would just use EnumMap<MyEnum, Boolean>, but unfortunately, EnumMap is not Serializable, since it has no nullary constructors. And why is this? Well, its constructors need to retrieve the list of enumeration values, and not only do Java generics erase the type information that would otherwise allow access to this info, but one also cannot call T.values() where T is a parameter type extending Enum. Basically, it's a whole pile of language-design fail.

I tried to get around all these issues by subclassing EnumMap and calling super(MyEnum.class) in the constructor, allowing it to be nullary (and therefore supporting serialization.) Ultimately, however, this code was rejected by GWT, and I found it easier to just write a specific reimplementation of the library code.

(Eclipse 3.4 x64 on Ubuntu Intrepid Ibex x64, GWT 1.6.4 plugin, ia32 Sun Java 5 libs.)

Alas, iguanas are not in the cards today. The Point is beautiful as always, though, with both smooth and jagged rock formations lining the sides. On the walk back to GRC I see a mangrove I hadn't noticed before, what might be a Bahama Mockingbird, and a yellow-flowered Wild Unction Vine.

Crab hiding under overhang

I packed the night before, so the only thing left to do before getting on the truck is to go down to the seashore and say goodbye to the island. I throw back the shells I had collected, but keep the smooth sea glass. A mid-sized crab scuttles under an overhang of the boat launch ramp I am standing on, and I nearly dip my camera into the surf to take a closeup photo. It comes out beautifully.

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The return trip is a breeze, except for the Nassau airport, where we have to go through Bahamian airport security, followed immediately by grumpy, power-tripping US Customs agents, and then through US airport security. Hey, handle that laptop gently, or at least don't slam it on the table! The San Sal airport was delightfully insecure, which made me feel relaxed. This harrying makes me anxious.

Finally, we are home. My mom picks us all up from the airport, and we watch the Tina James' Magic evening primroses open, exotic flowers in our own yard.

We walk down past the water tanks and through the catchment. Mr. Forbes points out a poisonwood tree for me. It's related to poison ivy and has the same toxin, urushiol, but he claims that the surface of the leaves is not toxic, only the sap. Either way, I'm glad to finally know one of the several plants to avoid touching. (Haulback and Manchineel are the others.) Our walk takes us down past one of the brackish inland lakes, where I have the misfortune of being the third person to brush past a wasp nest, and thus I am the one who is stung. Luckily, I have a steroidal cream in my backpack, which quickly cuts the inflammation and pain. However, we don't actually know where the nest is located, just that it's somewhere near or on the path.

As we head back, I am again the third person in the group, and my companions make it past the nest before I spot it. There it is, attached to a calf-height branch sticking out into the path. I try to ease past it, but at the last second half the nest launches. Only one gets a sting in (on the same leg) before they turn back. Again, the cream provides quick relief. (When we later see a similar nest near the path, I choose a wiser but more difficult route through the dense bush, circumnavigating the agitated wasps.)

The power cuts on again minutes after we arrive back at Gerace.

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The rest of the day is unscheduled, so my dad and Kathleen and I hop in the van and explore the island a little bit more. The lighthouse is our first stop. It is one of the last of its kind, and is open to the public. I take a series of photos of the island's landscape from the circular deck, which I hope to stitch into a panorama at a later date.

We have time for one last snorkel, and we choose Rocky Point. It has patches of real coral reef, more impressive than the occasional small coral anchored on a random bit of underwater debris. The water is 20 feet deep, so I get to dive down, roll onto my back, and watch the silvery waves billow overhead. I see giant sea fans, cleaner wrasse, and schools of tiny, translucent fish just below the surface. Kathleen spots a flounder hugging the sand. The current farther out is quite strong, so we struggle back to shore and call it a day.

We'll be leaving tomorrow morning, so after dinner I take a walk down the road to check out the flowering agaves. Once I've explored those as well as the dense roadside bush will permit, I walk further east. There are occasional overgrown driveways into equally overgrown abandoned lots, and in one of these I find a prickly pear cactus, a car's chassis that is nearly covered in vines, and various rusting discarded appliances. It seems to be the wrong time of year for prickly pear fruit, and I have no inclination to clean and cook a pad.

On the way back from breakfast I find a hermit crab that is far too small for its shell. I play with it a little bit (and get a tiny pinch), then set it down and go about my business. An hour later, I come across the shell... upside-down, with no crab! A faint set of tracks in the sand lead me to a rock, behind which is the naked hermit crab. (I've never seen this before.) The crab is super aggressive, but I get some okay pictures of it.

I know that hermit crabs whose scavenged shells are too small are less protected, but I had never considered what danger a crab with a too-large shell would face. It seems that when an oversized shell flips over, the crab has no choice but to exit the shell and search out a new one. I test this idea by allowing the naked crab to get back in its shell and then placing it upside-down. Although the crab never exits, it also doesn't succeed in flipping; it really would have no choice in the long run. (I right the crab and search for a more appropriately sized shell, but I can find none.)

After lunch, we interview Myrtis Jones at her house and learn of even more plants (such as Sweetwood) and new uses for others. (I believe she mentioned avocado leaf for pain, but I can't be sure.) Kathleen tastes a Noni fruit, and after sputtering a bit declares that it tastes just like it smells. (Specifically, horrible.)

We help Mr. Forbes run a few errands and arrange to meet him tomorrow. I hope I can get another tamarind pod!

More snorkeling after dinner, this time to the east of the sewage pipe. (We are informed that the currents carry the water west, where we were snorkeling the other day.) There is a sting-ray! We keep a respectful distance as it futzes around in the sand.