Programming Perl, 4th Edition

goto

goto LABEL
goto EXPR
goto &NAME

goto LABEL finds the statement labelled with LABEL and resumes execution there. If the LABEL cannot be found, an exception is raised. It cannot be used to go into any construct that requires initialization, such as a subroutine or a foreach loop. It also can’t be used to go into a construct that is optimized away. It can be used to go almost anywhere else within the dynamic scope,^[237] including out of subroutines; however, for that purpose, it’s usually better to use some other construct such as last or die. The author of Perl has never felt the need to use this form of goto (in Perl, that is—C is another matter).

Going to even greater heights of orthogonality (and depths of idiocy), Perl allows goto EXPR, which expects EXPR to evaluate to a label name, whose location is guaranteed to be unresolvable until runtime since the label is unknown when the statement is compiled. This allows for computed gotos per FORTRAN, but isn’t recommended if you’re optimizing for maintainability:

goto +("FOO", "BAR", "GLARCH")[$i];

The unrelated goto &NAME is highly magical, substituting a call to the named subroutine for the currently running subroutine. This construct may be used without shame by AUTOLOAD subroutines that wish to load another subroutine and then pretend that this new subroutine—and not the original one—had been called in the first place (except that ...