IOExceptions

[Aidan63]

The IOException type is rather awkward to use, especially if you look at it from a coroutine point of view. If, for example, I'm only interested in the file not being found and I'm fine with other exceptions being bubbled up I'd have to write something like this.

try {
	FileSystem.info(path).modificationTime;

	// do other stuff
} catch (exn:IOException) {
	if (exn.type.match(FileNotFound)) {
		return false;
	}

	// rethrow exceptions we're not handling...
	throw exn;
}

Usually I'm all for reducing inheritance but with the built in type checking of catches, having exception sub classes for each exception type makes for nicer code and less likely to accidentally swallow errors.

try {
	FileSystem.info(path).modificationTime;

	// do other stuff
} catch (_:FileNotFoundException) {
	return false;
}