The Python 2 to Python 3 migration has been incredibly painful, and there are still a huge number of people on Python 2. Ditto for Ruby 1.8 to 1.9.

Javascript has had a nightmarish compatibility and upgrade story.

Scheme and Erlang are fairly rigidly specified.

Clojure is young enough that breakage is treated as expected between versions.

Lisp is a whole family of languages - but if you mean Common Lisp, it's been extensively tied to an essentially fixed spec for a very, very long time.

for(split(" ","tsuJ rehtonA lreP rekcaH")){print reverse . " "}print "\b.\n";

In reply to Re^5: Make $^V and "my" implicit by pobocks
in thread Make $^V and "my" implicit by gunzip

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