I use Clojure for my skunkworks projects at work. I used to use Python, but when we dropped the product's native TCP/IP interface in favour of JMS, it became difficult to use Python any more, as the hoops you have to jump through to access JMS from Python were beyond my patience level.
However, it gave me a perfect excuse to use Clojure as, since it runs on top of the JVM, it makes access to JMS pretty easy. This was around Cloure 1.0, and I've migrated forward whenever a new release became available.
However, I put off the migration to 1.3 because the break-up of the
clojure-contrib library meant it would probably take a little bit
of work. When I did find the time, it wasn't that
onerous. Here's a summary of the changes I had to make:
I had put
(clojure.contrib.repl-utils/add-break-thread!) in
user.clj to allow the interruption of a long running
function in the REPL (I use emacs with Jeffrey Chu's
clojure-mode. This has been replaced with
(clojure.repl/set-break-handler!). You'll need to
include (require 'clojure.repl) in user.clj as
well. See the
changelog, point 2.28.
The funtions to access function documentation doc and
find-doc have moved into clojure.repl, in case
you wondered where they had gone. See the
changelog, point 2.26.
Access to the server data was through
clojure.contrib.sql, which has been replaced by clojure.java.jdbc.
It was a bit tricky to track down the ready-made jar, but the
link will take you there. This, for me, was a drop-in
replacement. Other namespace changes for the clojure-contrib
libraries are documented at
clojure.org.
I found I had to (require 'clojure.xml) and (require
'clojure.zip), which was not needed under 1.2. See the
changelog, point 1.4.
The function clojure.xml/emit, for outputting xml in a
string format from a zip structure, is no longer public (but still
available) in 1.3. It will probably disappear in a later version
but, hopefully, some other mechanism will be available by then.
Dynamic vars must be explicity tagged with ^:dynamic when
they are defined. Earmuffs, i.e. *var*, are no longer
sufficient. See the
changelog, point 1.1.
One thing caught me by surprise when I was testing the converted
programs: the XML messages I was sending the server produced
errors. This was because every token was terminated by "\r\n".
I generated the xml by something like this, removing the
newlines inserted by clojure.xml/emit:
(.replace (with-out-str (clojure.xml/emit (clojure.zip/node xml-zip))) "\n" "")
A bug in 1.2 had been fixed, as now with-out-str
emits the line separator for the platform, rather than "\n". To
reflect this, I changed the snippet to:
(.replace (with-out-str (clojure.xml/emit (clojure.zip/node xml-zip)))
(System/getProperty "line.separator") "")
See the changelog, point 2.24.
