add define-struct-lenses and struct/lens

[AlexKnauth]

No description provided.

[AlexKnauth]

The Travis CI build is failing because the package server hasn't updated yet after a new feature in the alexis-util package, but you should restart the build once the package server updates.

[AlexKnauth]

Ok the package server updated and I added more tests, rebased, and pushed, and now the build is passing.

[jackfirth]

Can some of this functionality be broken up into one or more helper macros to simplify the implementation?

[AlexKnauth]

Huh. Why is the travis build failing on the main repo now? It was working fine on the PR build, and it works fine for me.

[jackfirth]

Not sure, some sort of complaint about the foo-a-lens. Rebuilding just to verify it wasn't a one-off.

[AlexKnauth]

It's complaining about foo-a-set not being defined, where define-struct-updaters from alexis/util/struct should have defined it.

[AlexKnauth]

Actually, it seems like the error is coming from the other struct.rkt, which is lens/struct, not the new one I added, which is unstable/lens/struct.

[AlexKnauth]

Oh. Is Travis by any chance getting the old version of the alexis-util package?
Because it's also complaining about an unknown module which was added to alexis-util recently:
https://travis-ci.org/jackfirth/lens#L265

require: unknown module
  module name: #<resolved-module-path:(submod "/home/travis/.racket/6.1.1/pkgs/alexis-util/alexis/util/struct.rkt" get-struct-accessors)>

[jackfirth]

That's definitely the problem, as I can install this locally on my machine with no trouble. I wonder why it's getting the old version?

[AlexKnauth]

I looked on the package server to see if it was up to date, but I found that alexis-util has a version exception for 6.1.1 pointing to another branch, and it seems like that branch isn't up to date.

I wonder though: Why did Travis get the up-to-date version when it was building this pull request?

[jackfirth]

There've been some commits today, that's all I can think of that's changed since this was last built and now.

[AlexKnauth]

I don't think that's it. It's complaining about this missing module, and that wouldn't happen unless it was getting the old version of alexis-util. Did the version exception not exist then? That would explain it.

[jackfirth]

Travis should probably be upgraded to build with 6.2 anyway. Or maybe it should build with a proper build matrix and use both 6.2 and 6.1.1

[jackfirth]

Yup it's definitely the version exception. #119 builds on 6.2 in Travis but not 6.1.1

[lexi-lambda]

@jackfirth @AlexKnauth Yep, looks like I broke alexis-util on 6.1.1 earlier, but it should be fixed now. Restarting the builds should fix the problem. I apologize for the inconvenience.

[jackfirth]

No trouble, builds installing fine now. Thanks for the quick fix @lexi-lambda