Trigger: what rows were deleted?

I'm trying to make a trigger, fired by DELETE. The associated function
needs to know what rows were deleted in order to perform a DELETE in
another table as well. (Foreign keys are not acceptable.) I don't seem
to be able to find this kind of info being passed to the function. The
special vars don't seem to have something useful. The arguments to the
trigger could help, but can they be made dynamical? Is there any way
of identifying the affected rows?

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Ciprian Popovici