Question

我的功能是

use 5.028;
use strictures;
use Kavorka qw(fun);

fun foobar(:$foo, :$bar) { say $foo, $bar; }

我需要传递命名参数，而不是位置参数。

foobar('quux', 'quuuux');
# Unknown named parameter: quux at … line 5.
#         main::foobar("quux", "quuuux") called at … line 7

但是

foobar(foo => 'quux', bar => 'quuuux');
# ok

Hash或HashRef也被接受。

my %args = (foo => 'quux', bar => 'quuuux');
foobar(%args);
my $args = {foo => 'quux', bar => 'quuuux'};
foobar($args);

ES6中存在一个快捷方式，其中扩展了对象文字中的变量（ed：MDN链接？）：

function foobar({foo, bar}) { console.log(foo, bar); }
foobar({foo: 'quux', bar: 'quuuux'});
const foo = 'quux';
const bar = 'quuuux';
foobar({foo: foo, bar: bar});
foobar({foo, bar}); // NB!

In Perl 6 a : prefixed variable in a parameter signature will create a key of the same name：

use v6;
sub foobar(:$foo, :$bar) { say $foo, $bar; }
foobar(foo => 'quux', bar => 'quuuux');
my $foo = 'quux';
my $bar = 'quuuux';
foobar(foo => $foo, bar => $bar);
foobar(:$foo, :$bar); # NB!

如何实现与Perl 5相当的效果？

my $foo = 'quux';
my $bar = 'quuuux';
foobar(???);

Answer 1

我有两种方法可以使用PadWalker（感谢建议暴民）或Hash Slices：

use strict;
use warnings;
use Data::Dumper;
use PadWalker qw/ var_name /;

sub test_sub { print Dumper [ @_ ] }

my %vars;

$vars{foo} = "foo_data";
$vars{bar} = "var_data";

test_sub( %{vars}{qw/ foo bar/} );

# nv = named variables ( rename as needed )
sub nv { map { ( substr( var_name(1, \$_), 1) => $_ ) } @_ }

my $foo = 'foo_stuff';
my $bar = 'bar_stuff';

test_sub( nv( $foo, $bar ) );

哪个给：

$VAR1 = [
          'foo',
          'foo_data',
          'bar',
          'var_data'
        ];
$VAR1 = [
          'foo',
          'foo_stuff',
          'bar',
          'bar_stuff'
        ];

必须在nv中进行替换，否则会显示出印记，但这就是我不考虑更深层次的魔术就能想到的最好的东西。

如果不使用nv，则需要进行更深入的魔术操作...

也使用您的Kavorka代码：

use 5.020;
use strictures;
use Kavorka qw(fun);
use PadWalker qw/ var_name /;

fun foobar(:$foo, :$bar) { say $foo, $bar; }

my %vars;

$vars{foo} = "foo_data";
$vars{bar} = "var_data";

foobar( %{vars}{qw/ foo bar/} );

# nv = named variables ( rename as needed )
sub nv { map { ( substr( var_name(1, \$_), 1) => $_ ) } @_ }

my $foo = 'foo_stuff';
my $bar = 'bar_stuff';

foobar( nv( $foo, $bar ) );

给予：

foo_datavar_data
foo_stuffbar_stuff

不幸的是，我没有在本地安装5.28

适当命名变量中命名参数的快捷方式

1 个答案: