Languages need to evolve, but when C evolved into different varieties, ultimately, it was called a different language. The same seems to be true of Perl.

update: A new attempt at expressing my thought: The difference between Perl 5 and 6 is much greater than the relative difference between C and C++. The code for my last C project the C code needed to be compatible with 4 compilers, 2 in C and 2 in C++. This is possible when writing new C code; however, an arbitrary existing program may or may not compile with a C++ compiler.

It is true that interfacing C and C++ binaries complied under different compliers can be problematic because at a fundamental level, each language uses a different subroutine calling protocol. In C the calling program manages the assembly lauguage stack. In C++, the callee (the subroutine) manages the assembly lauguage stack.

But this linking difference does not rise to the level of "a different language", at least not at the source code level.

If you like OO, the big difference in Perl over the past years has been better ways of doing it. Perl 5 OO has become much easier than it used to be.

I will leave it to other Monks to talk about Perl 5 OO, Moose, Moo and the tools that have become mainstream Perl 5 OO for users.

If you have older Perl 5 OO code, there is no problem running it together with more modern Perl 5 OO implementations. I suggest you become more informed about Perl 5 advances since you last used Perl in an OO environment.

Perl 6 is a completely different language from Perl 5. This is not at all like C versus C++.