Perl 学习手札之十六： New features in Perl 5.10

heshao2005

　　Using Perl 5.10 features
　　perl 5.10 includes new language features
　　incompatible with previous version

　　


use feature ':5.10';
use feature qw(switch say state);
use 5.010　　say feature.


#!/usr/bin/perl
#
use strict;
use warnings;
use feature ":5.10";
main(@ARGV);
sub main
{
    say "This is the Perl 5.10 new features exercise file.";
    say "this is another line";
}
sub error
{
    my $e = shift || 'unkown error';
    my $me = ( split(/[\\\/]/, $0 ) )[-1];
    print("$me: $e\n");
    exit 0;
}　　switch feature:

　　switch.pl



#!/usr/bin/perl
#
use strict;
use warnings;
use feature ":5.10";
main(@ARGV);
sub main
{
    my $s='jimi hendrix';#5
    given($s){
        when(undef){say'$s is undefined'}
        when('jimi'){say'$s is musician'}
        when(/jimi/){say'$s maybe a muscian'}
        when([1,3,5,7,9]){say'$s is odd number'}
        default{say '$s is something else!'}
    }
}
sub error
{
    my $e = shift || 'unkown error';
    my $me = ( split(/[\\\/]/, $0 ) )[-1];
    print("$me: $e\n");
    exit 0;
}　　state feature;

　　state.pl


#!/usr/bin/perl
#
use strict;
use warnings;
use feature ":5.10";
main(@ARGV);
sub main
{
    my $i = 5;
    increment($i);
    increment($i);
    increment($i);
    increment($i);
}
sub increment{
    state $n = shift;
    say ++$n;
}
sub error
{
    my $e = shift || 'unkown error';
    my $me = ( split(/[\\\/]/, $0 ) )[-1];
    print("$me: $e\n");
    exit 0;
}　　注意此时的state关键字，如果用my替换，运行结果会不同！

　　到此为止，Perl学习手札的更新，告一段落。进阶更新待定