perl - 在此处的文档中插入常量的首选方法是什么？

Question

我确定有几种方法可以将值“bar”插入到下面的 <> 中，但最干净的方法是什么，为什么？

use constant FOO => 'bar';

my $msg = <<EOF;
Foo is currently <whatever goes here to expand FOO>
EOF

Answer 1

使用 Const::Fast而不是 Readonly或 constant .他们在没有任何扭曲的情况下进行插值。见 CPAN modules for defining constants :

For conditional compilation, constant is a good choice. It's a mature module and widely used.

...

If you want array or hash constants, or immutable rich data structures, use Const::Fast. It's a close race between that and Attribute::Constant, but Const::Fast seems maturer, and has had more releases.

另一方面，您似乎正在编写自己的模板代码。别。相反，使用简单的东西，比如 HTML::Template :

use HTML::Template;

use constant FOO => 'bar';

my $tmpl = HTML::Template->new(scalarref => \ <<EOF
Foo is currently <TMPL_VAR VALUE>
EOF
);

$tmpl->param(VALUE => FOO);
print $tmpl->output;