[racket] Is there a URL representing the latest nightly build installer for a platform?

Thanks Matthew for adding the new abstract URL!

I updated travis-racket to use this. In your build matrix you can now
specify `HEAD` as well as versions like `5.3.6`.

For example this .travis.yml runs a build against 3 versions of
Racket, 1 of which is HEAD:

~~~

language: c

# Supply at least one RACKET_VERSION environment variable definition
# here. RACKET_VERSION is used by the install-racket.sh script
# (specifed below under before_install) to select the version of
# Racket to download and install.
#
# If you supply more than one, you can create multiple builds (a
# Travis-CI build matrix resulting in multiple builds). You can use
# this to test against multiple Racket versions.
env:
 - RACKET_VERSION=5.3.4
 - RACKET_VERSION=5.3.5
 - RACKET_VERSION=HEAD

before_install:
 - curl -L https://github.com/greghendershott/travis-racket/releases/download/v0.3/install-racket.sh
| sh

install:

before_script:

# Here supply steps such as raco make, raco test, etc.  Note that you
# need to supply /usr/racket/bin/ -- it's not in PATH. You can run
# `raco pkg install --deps search-auto <pkg>` to install any required
# packages without it getting stuck on a confirmation prompt.
script:
 - /usr/racket/bin/raco make main.rkt
 - /usr/racket/bin/raco test -x .

~~~

https://github.com/greghendershott/travis-racket


On Wed, Oct 16, 2013 at 8:41 PM, Greg Hendershott
<greghendershott at gmail.com> wrote:
> I'm using Travis CI for a number of my projects, to test them against
> recent Racket releases.
>
> Sam had a great suggestion: Add 5.90.x to the build matrix. [1]
>
> I could update my .travis.yml to use e.g.
> http://www.cs.utah.edu/plt/snapshots/current/installers/racket-5.90.0.9-x86_64-linux-precise.sh
>
> That would work great...for awhile. But what happens if the version
> rolls to 5.90.0.10?  I'd be fetching the old, wrong thing until
> someone noticed.
>
> Instead: Is there some "abstract" URL meaning (a) the latest version
> (b) of a platform like x86_64-linux-precise?
>
> For example instead of
>
>   ... current/installers/racket-5.90.0.9-x86_64-linux-precise.sh
>
> it would be (say)
>
>   ... current/installers/latest/x86_64-linux-precise.sh
>
>
> Note that I don't care what the actual filename ends up being. So this
> abstract URL could be a 302 Found redirect where the Location response
> header is whatever the specific version happens to be, just like the
> status quo.
>
> (I suppose anyone, even I, could set up such a redirect server. The
> problem would be coordinating it with the HEAD version bumps, and
> manually updating the redirect at the same time the version bumps. So
> same problem, just whacka-moled elsewhere.)
>
>
> [1]: https://github.com/greghendershott/frog/issues/56