Multiple versions of boost.

[Roel Janssen]

Dear list,

In my list of packages, I find older versions of Boost.  Specifically,
version 1.57.0 and version 1.56.0.  In Guix we've got version 1.60.0.

I would like to add the older versions as packages as well, and my
current approach is to inherit most of the 1.60.0 package:

(define boost-1.57.0
  (package (inherit boost)
    (name "boost")
    (version "1.57.0")
    (source (origin
              (method url-fetch)
              (uri (string-append
                    "mirror://sourceforge/boost/boost_"
                    (string-map (lambda (x) (if (eq? x #\.) #\_ x)) version)
                    ".tar.bz2"))
              (sha256
               (base32
                "0rs94vdmg34bwwj23fllva6mhrml2i7mvmlb11zyrk1k5818q34i"))))))


Is this a workable approach?  If not, how could I go about adding
multiple versions?

My other questions:
- What is the convention with the Scheme variable name for the package?
- Should I distinguish the package name in its version?

Thank you for your time.

Kind regards,
Roel Janssen