Thank you, this is what I was looking for. I have a similar experience with string eval, generating subroutines that access certain data fields, using a configuration file. This was done to improve performance, as the generated subroutines were fine-tailored to the data extraction task at hand (with completely non-generic statements like substr($str, 2, 13)).
Unlike what many think, although the string eval is dangerous, it is necessary to efficiently and generically implement certain things that are impossible without it. The terrific "Higher Order Perl" has a lot of examples for smart usage of eval, and I'll look there as well.