Perl 5.6.0 is almost a decade old; perldoc perlhist gives a release date of 22 March 2000.
My favorite feature of Perl 5.6.0 is lexical filehandles. Instead of having
to access the IO slot of package global typeglobs, I could use lexical
variables to contain filehandles -- without having to muck about
localizing symbol tables or worrying about action at a distance or
lifetimes of global symbols.
Yet to this day, almost a decade later, I still see the old way with all of its disadvantages (Tell the truth; do you understand every word of "the IO slot of package global typeglobs"? Do you want to explain that to novice programmers?) in new code.
Perl 5.6.2 is long dead. Perl 5.8.9 is the last of its release series too. The argument for running new code on old installations of Perl 5 is awfully thin, in that light.
Likewise I can't make a simplicity argument for the old approach. Making
old-style filehandles work like people might expect is anything but simple.
Throw in a
local here or there and the typeglob sigil and maybe a
gensym() call for good measure. Fun!
Reasonable people differ on style and technique, but I wonder what makes a feature such as pseudohashes or 5.005-style threads so hated that it eventually gets deleted, while difficult-to-use-correctly features superseded by better replacements stick around far longer than necessary. My guess is that the Perl 5 world suffers here, as usual, from a questionable abundance of old code, old tutorials, old books, and copy and paste coding from ancient sources of dubious wisdom. (This probably means I should submit patches to perldoc perluniintro and other offenders in the core documentation.)
Perhaps it's time to consider a gradual, intentional, well-tested and well-reviewed campaign to update tutorials and example code with somewhat more modern examples of maintainable Perl.
(For fun, imagine a world where the canonical printed Perl 5 reference covered a version of Perl 5 released this millennium. Then again, Perl.com thinks that 5.6.2 is "the previous version of Perl" 5.)