perl - 如何让子程序具有所需的参数？

Question

是否可以在 Perl 中声明一个子例程，以便在调用脚本时如果未向其传递参数，脚本将无法编译？

Answer 1

我认为这种事情是你目前能做的最好的事情:

#!/usr/local/bin/perl -w
use strict;
require 5.020;
use warnings;
use feature qw( say signatures );
no warnings "experimental::signatures";

print "Enter your first name: ";
chomp(my $name1 = <STDIN>);

print "Enter your last name: ";
chomp(my $name2 = <STDIN>);

say "Calling takesOneOrTwoScalars with 2 args";
takesOneOrTwoScalars($name1, $name2);

say "Calling takesOneOrTwoScalars with 1 arg";
takesOneOrTwoScalars($name1);

say "Calling takesOneOrTwoScalars with 0 args";
takesOneOrTwoScalars();

sub takesOneOrTwoScalars($firstName, $lastName="")
{
    print "Hello, $firstName";
    if ($lastName)
    {
        say " $lastName";
    }
    else
    {
        say ", I see you didn't give your last name.";
    }
}