Ruby 中的多行注释？

Question

如何在 Ruby 中注释多行？

Answer 1

#!/usr/bin/env ruby

=begin
Every body mentioned this way
to have multiline comments.

The =begin and =end must be at the beginning of the line or
it will be a syntax error.
=end

puts "Hello world!"

<<-DOC
Also, you could create a docstring.
which...
DOC

puts "Hello world!"

"..is kinda ugly and creates
a String instance, but I know one guy
with a Smalltalk background, who
does this."

puts "Hello world!"

##
# most
# people
# do
# this


__END__

But all forgot there is another option.
Only at the end of a file, of course.

• 这就是它的样子（通过屏幕截图） - 否则很难解释上面的评论会是什么样子。 点击放大：

Answer 2

=begin
My 
multiline
comment
here
=end

Answer 3

尽管存在 =begin 和 =end，但正常且更正确的注释方法是在每一行上使用 #。如果您阅读任何 ruby​​ 库的源代码，您会发现这就是几乎所有情况下多行注释的完成方式。

Answer 4

#!/usr/bin/env ruby

=begin
Between =begin and =end, any number
of lines may be written. All of these
lines are ignored by the Ruby interpreter.
=end

puts "Hello world!"

Answer 5

使用：

=begin
This
is
a
comment
block
=end

或

# This
# is
# a
# comment
# block

是 rdoc 当前支持的唯一两个，我认为这是仅使用这些的一个很好的理由。

Answer 6

=begin
comment line 1
comment line 2
=end

确保 =begin 和 =end 是该行的第一件事（没有空格）

Answer 7

这是一个示例：

=begin 
print "Give me a number:"
number = gets.chomp.to_f

total = number * 10
puts  "The total value is : #{total}"

=end

您放置在 =begin 和 =end 之间的所有内容都将被视为注释，无论其之间包含多少行代码。

注意：确保=和begin之间没有空格：

• 正确：=begin
• 错误：=开始

Answer 8

=begin
(some code here)
=end

并且

# This code
# on multiple lines
# is commented out

都是正确的。第一种注释类型的优点是可编辑性 - 更容易取消注释，因为删除的字符较少。第二种注释的优点是可读性——逐行阅读代码，更容易看出特定行已被注释掉。你的电话，但想想谁会追随你，以及他们阅读和维护是多么容易。

Answer 9

如果有人正在寻找一种注释多行的替代方法，例如：

<%
=begin
%>
  ... multiple HTML lines to comment out
  <%= image_tag("image.jpg") %>
<%
=end
%>

可以替换为：

<% if false # The following section is commented out because... %>
  ... multiple HTML lines to comment out
  <%= image_tag("image.jpg") %>
<% end # if false %>

这不是严格的注释，因为有一个 if 语句，因此对 CPU 的使用很小，所以我不会不要在频繁运行的代码中使用此类资源。

但有时我发现它更有吸引力。

有谁知道这种做法的主内存使用是否有差异？

Answer 10

  def idle
    <<~aid
    This is some description of what idle does.

    It does nothing actually, it's just here to show an example of multiline
    documentation. Thus said, this is something that is more common in the
    python community. That's an important point as it's good to also fit the
    expectation of your community of work. Now, if you agree with your team to
    go with a solution like this one for documenting your own base code, that's
    fine: just discuss about it with them first.

    Depending on your editor configuration, it won't be colored like a comment,
    like those starting with a "#". But as any keyword can be used for wrapping
    an heredoc, it is easy to spot anyway. One could even come with separated
    words for different puposes, so selective extraction for different types of
    documentation generation would be more practical. Depending on your editor,
    you possibly could configure it to use the same syntax highlight used for
    monoline comment when the keyword is one like aid or whatever you like.

    Also note that the squiggly-heredoc, using "~", allow to position
    the closing term with a level of indentation. That avoids to break the visual reading flow, unlike this far too long line.
    aid
  end

请注意，在发布本文时，stackoverflow 引擎无法正确渲染语法着色。测试它在您选择的编辑器中的呈现方式可以作为练习。 ;)