Is there a way to avoid string evals here by rebinding a clone of a subroutine to a new package, so that SUPER resolution will start from that other class?

I'm not aware of any way of retargetting SUPER resolution. I have some similar but different needs in my work application, and I solve them by injection: I construct a class specific to the caller which is injected into the caller's @ISA, and use string eval to recompile each of the methods supplied by the mixin into that class.

So in one module I might have:

  package NVC::DB::User;
  our @ISA = qw/ NVC::DB /;
  use NVC::DB::attr qw/ cache /;
  ...

[download]
and NVC::DB::attr will create a class NVC::DB::cache::User into which to inject the extra methods, and set:
  @NVC::DB::cache::User::ISA = @NVC::DB::User::ISA;
  @NVC::DB::User::ISA = qw/ NVC::DB::cache::User /;

[download]

Since I'm using the string eval anyway, I take advantage of it to construct mixin methods specific to the adopting class rather than creating catch-all methods that do runtime tests to determine the correct behaviour for the class. So, for example, the cache mixin uses different code depending whether the adopting class has a single key field or multiple key fields.

Since this is all transparent to the adopter, I can turn caching on or off by adding or removing use NVC::DB::attr qw/ cache /; in the class definition.

Hugo

In reply to Re: Solving the SUPER problem in Mixins with String Eval by hv
in thread Solving the SUPER problem in Mixins with String Eval by simonm

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