Safely and cleanly create closures via string eval
Description
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's easy to miss
compilation errors, since eval catches them and sticks them in $@ instead. This
module attempts to solve these problems. It provides an eval_closure function,
which evals a string in a clean environment, other than a fixed list of specified
variables. Compilation errors are rethrown automatically.
