There are several defined ways of differentiating scripts as a whole. A minimal approach allows for a bare literal in void context at the beginning: 
    5; print "I'm Perl 5 code\n";

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vs 
    6; say "I'm Perl 6 code";

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Or if you want to make sure strictness is on, you use 
    use 6.0;

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or 
    module;

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Those are okay for the script as a whole, but I hate to think about what happens when people start cutting and pasting snippets. Certainly Perl 6 could disallow snippets starting with "5;", but Perl 5 would currently accept a "6;" unless you had warnings turned on. One could go with "5:" and "6:" instead, but that's a syntax error in Perl 5 currently.

Of course, there's always the tried and true: 

    print "I'm Perl 5 code\n";  # Perl 5

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vs 
    say "I'm Perl 6 code";      # Perl 6

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But that doesn't help much with cut-and-paste errors...

In reply to Re^7: Parrot Monks? (one ring) by TimToady
in thread Parrot Monks? by Thilosophy

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