将正则表达式替换作为变量传递给Perl? [英] Passing a regex substitution as a variable in Perl?

问题描述

我需要将正则表达式替换作为变量传递:

I need to pass a regex substitution as a variable:

sub proc {
    my $pattern = shift;
    my $txt = "foo baz";

    $txt =~ $pattern;
}

my $pattern = 's/foo/bar/';
proc($pattern);

这当然是行不通的.我尝试评估替换:

This, of course, doesn't work. I tried eval'ing the substitution:

eval("$txt =~ $pattern;");

但是那也不起作用.我在这里想念的是什么可怕的东西?

but that didn't work either. What horribly obvious thing am I missing here?

推荐答案

我需要将正则表达式替换作为变量传递

I need to pass a regex substitution as a variable

你呢?为什么不通过代码引用?示例:

Do you? Why not pass a code reference? Example:

sub modify
{
  my($text, $code) = @_;
  $code->($text);
  return $text;
}

my $new_text = modify('foo baz', sub { $_[0] =~ s/foo/bar/ });

通常，当您要将某事做某事"传递给子例程(对于您的问题，是正则表达式替换")，答案是传递对一段代码的引用. 高级Perl 是一本关于该主题的好书.

In general, when you want to pass "something that does something" to a subroutine ("a regex substitution" in the case of your question) the answer is to pass a reference to a piece of code. Higher Order Perl is a good book on the topic.

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