"could not create val_spec" is not very helpful
When one is missing the penultimate unit parameter in the *_specs.txt file, this is the error message to get. There could be a more helpful message, or at least that would be nice.
luckily, the function spec for which the generation failed is printed just before, but still it took me some time to realize what was wrong with my spec.
Yeah, you've hit one of the items on my to do list...the error messages are generally pretty unhelpful. I still haven't gotten the hang of getting angstrom to produce nice error messages, to be honest. But I agree, they aren't that helpful as is, and need some work.
I added a bit more info to some of the failures. I wouldn't call the problem fixed, but it's moving in a better direction at least.