Perl 5 had compile-time execution forever. And this feature is used in everyday's code as that feature is at the core of the implementation of exporting symbols

Perl 5 had compile-time execution forever. And this feature is used in everyday's code as that feature is at the core of the implementation of exporting symbols from a module into its importer (See module Exporter). Example: the BEGIN block is executed during the compile phase as the parser encounters it. The code injected in BEGIN blocks can affect how the rest of the file is parsed. $ perl -E 'exit; BEGIN { say "Hello" }' Hello "perl -c" stops the program after compile, but before execution. In the following code the BEGIN block runs, but not "exit 1". $ perl -c -E 'exit 1; BEGIN { say "Hello" }'; echo $? Hello -e syntax OK 0 More info: * https://perldoc.perl.org/perlmod#BEGIN,-UNITCHECK,-CHECK,-INIT-and-END https://perldoc.perl.org/perlmod#BEGIN,-UNITCHECK,-CHECK,-IN... * https://perldoc.perl.org/perlfunc#use-Module-VERSION-LIST https://perldoc.perl.org/perlfunc#use-Module-VERSION-LIST