Compile-time Manipulation

Unlike code written explicitly as code, code generated through string eval gets compiled while our program is running. Where we might expect a normal function to be available throughout the lifetime of our program, a generated function might not be available when we expect it.

The BEGIN block

Force Perl to run code—to generate other code—during compilation by wrapping it in a BEGIN block. When the Perl parser encounters a block labeled BEGIN, it parses and compiles the entire block and then runs it (unless it has syntax errors). When the block finishes running, parsing ...