P5-eval-closure

Safely and cleanly create closures via string eval

String eval is often used for dynamic code generation. For instance, Moose uses it heavily, to generate inlined versions of accessors and constructors, which speeds code up at runtime by a significant amount. String eval is not without its issues however - it’s difficult to control the scope it’s used in which determines which variables are in scope inside the eval, and it can be quite slow, especially if doing a large number of evals.

This module attempts to solve both of those problems. It provides an eval_closure function, which evals a string in a clean environment, other than a fixed list of specified variables. It also caches the result of the eval, so that doing repeated evals of the same source, even with a different environment, will be much faster but note that the description is part of the string to be evaled, so it must also be the same or non-existent if caching is to work properly.