Give better error messages when dependencies are not present (#60)
- Give better error messages when dependencies are not present
This way in the common case where a dependency is not present we will give a better error than “attribute missing”.
This will bloat the size of the generated files a bit since a lot of the
messages are repeated, but I couldn’t see a nice way to do it otherwise
while keeping the
ToNixExpr functions self-contained.
I was a little bit unsure about
ExeDependency - I think it’s trying
to look in
components.exes although at the moment it just looks at the
ambient scope. I made this explicit.