Macros.
Now that you mention them it occurs to me that another desirable feature could be the possibility of creating user defined (infix, postfix, postcircumfix, etc.) operators. But I doubt that even hypothetically this could be doable without anything close to Perl6's powerful prototyping.

In reply to Re^2: (Sort of) poll: what Perl6 features do you consider {likely,desirable} to leak into P5? by blazar
in thread (Sort of) poll: what Perl6 features do you consider {likely,desirable} to leak into P5? by blazar

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