Perl has a syntax called “indirect method notation”. It allows
Foo->new($bar)
to be written as
new Foo $bar
So that means
Syntax error ! exit 0;
is the same as
error->Syntax(! exit 0);
or
error->Syntax(!exit(0));
Not only is it valid syntax, it doesn’t result in a run-time error because the first thing executed is exit(0)
.