Summary

1. 习惯

• 在.pl文件开头加上
  • use strict;
  • use warnings;

2. 用于变量的关键字

• my 局部变量
• local 局部全局变量
• our 全局变量
• state 静态变量, 需要加上use feature 'state';

2.1. my VS local

# `my` vs `local`

use strict;
use warnings;

$a = 1;

sub printA {
    print($a, "\n");
}

sub funcMy {
    my $a = 2;
    printA();
}

sub funcLocal{
    local $a = 3;
    printA();
}

printA();
funcMy();
funcLocal();
printA();

3. sort

use strict;
use warnings;

# sort 排序
=pod
sort LIST
sort SUBROUTINE LIST
=cut

sub printL {
    my $str = join(' -> ', @_);
    print($str, "\n");
}

sub f_bigger {
    return $a lt $b;
}

my @a = ('b', 'd', 'c', 'a');

my @b = sort(@a);

my @c = sort(f_bigger, @a);

printL(@a);
printL(@b);
printL(@c);