On Tue, Jun 7, 2011 at 08:51, Yitzchak Gale
Since the whole idea of xml-types is for it to be a unifying standard, I'd like to see it usable in that kind of environment, too.
It is usable in such an environment -- simply do not use the IsString instance.
In addition, I have already pointed out that semantically it doesn't make sense for a fromString implementation to return _|_. And it is easy to make a small change to the current implementation to avoid that.
So let me turn the question around. Is there a compelling reason why, in some use case, the fromString must return _|_, rather than returning some text that will allow the application to handle the situation itself?
The string "foo}bar" is invalid; it must *never* be converted to a Name. Doing so would cause silent, unpredictable failures which cannot be tested for. IsString does not support reporting parse errors; therefore, any IsString instance for Name must be partial. if you're very concerned about it, I could add a flag like "NoIsString" which disables that particular instance. You could enable it in your build scripts. However, I will not implement a change which can cause arbitrary silent failure with no obvious cause.