ruby - 当 Ruby 正则表达式不适合在线时

Question

当我有一个很长的正则表达式时，比如黄瓜步骤定义，换行的最佳方法是什么？

例如，我想要类似的东西：

When /^I have a very long step definition here in my step definition file$/ do
  ...
end

分成两行（这不起作用:)

When /^I have a very long step definition here in /\
    /my step definition file$/ do
  ...
end

---

2018 年更新

如果您是专门为黄瓜而来的，那么使用黄瓜表达式是正则表达式的绝佳替代品

Answer 1

您可以使用带有修饰符的详细正则表达式/x，但是您需要明确空格，否则它们将被忽略。另一个优点是这允许您评论您的正则表达式（如果它很长，可能是一个好主意）：

/^                               # Match start of string
I[ ]have[ ]a[ ]very[ ]long[ ]
step[ ]definition[ ]here[ ]
in[ ]my[ ]step[ ]definition[ ]file
$                               # Match end of string
/x

Answer 2

字符串到正则表达式的转换呢？你会失去语法突出显示，但我会说这还不错？

When( Regexp.new(
  '^My long? regex(?:es) that are '\
  '(?:maybe ) broken into (\d+) lines '\
  'because they (?:might )be non-readable otherwise$'
)) do |lines|
  ...
end
# => /^My long? regex(?:es) that are (?:maybe ) broken into (\d+) lines because they (?:might )be non-readable otherwise$/

Answer 3

关于什么

/a\
b/
# => /ab/

Answer 4

I know you want it in Ruby, but i can give you an example how it can be realised in Perl. I really think that you can use the idea behind this in Ruby as well.

my $re1 = "I have a very long step definition here in";
my $re2 = "my step definition file";

if ( $line =~ m/^$re1 $re2$/i ) {
    ...
}

The idea is to save the Regex into a variable and write the variable inside the regex.