使 diff-lcs 的输出具有人类可读性

Question

我正在使用 diff-lcs gem 来输出两个 html 内容主体之间的差异。这是示例内容。

版本一：

<p>Paragraph one. Sentence one.</p>

<p>Paragraph two. Another sentence.</p>

<p>Paragraph three. I dare you to change me!</p>

第二版：

<p>Paragraph one. Sentence two.</p>

<p>Paragraph two. Another sentence.</p>

<p>Paragraph three. I dare you to update me!</p>

使用这个：

seq1 = @versionOne.body
seq2 = @versionTwo.body

seq = Diff::LCS.diff(seq1, seq2)

你得到了这个怪物：

seq => [[#<Diff::LCS::Change:0x0000000be539f8 @action="-", @position=27, @element="t">, #<Diff::LCS::Change:0x0000000be538b8 @action="-", @position=28, @element="w">], [#<Diff::LCS::Change:0x0000000be53520 @action="+", @position=28, @element="n">, #<Diff::LCS::Change:0x0000000be53408 @action="+", @position=29, @element="e">], [#<Diff::LCS::Change:0x0000000be3aa70 @action="-", @position=110, @element="u">, #<Diff::LCS::Change:0x0000000be3a840 @action="-", @position=111, @element="p">, #<Diff::LCS::Change:0x0000000be34ee0 @action="-", @position=112, @element="d">, #<Diff::LCS::Change:0x0000000be349e0 @action="+", @position=110, @element="c">, #<Diff::LCS::Change:0x0000000be348a0 @action="+", @position=111, @element="h">], [#<Diff::LCS::Change:0x0000000be34580 @action="-", @position=114, @element="t">, #<Diff::LCS::Change:0x0000000be34210 @action="+", @position=113, @element="n">, #<Diff::LCS::Change:0x0000000be33f40 @action="+", @position=114, @element="g">], [#<Diff::LCS::Change:0x0000000be331d0 @action="-", @position=124, @element="">]]

sdiff 的输出和the documentation 中的其他方法同样令人恐惧。我了解数组（数组）的结构，但必须有一种简单的方法以人类可读和可样式化的方式显示差异。

PS - 如果有人想创建diff-lcs 标签，我们将不胜感激。

Answer 1

我输入的 diff-lcs 是一个常规字符串 - 一个字符数组。如果我想要的是字符的比较，我得到了我想要的，但我想要更易读的东西——单词、行或句子的比较。我选择了句子。

seq1 = @versionOne.body.split('.')
seq2 = @versionTwo.body.split('.')
compareDiff = Diff::LCS.sdiff(seq1, seq2)

这产生了更具可读性和可解析性的内容。实际上，我还想按! 和? 分开。然而，该结构不是普通的数组或哈希数组。浏览器中的输出让我大吃一惊，但它是一个对象数组，你可以像其他任何东西一样解析它。这是我在 rails 控制台中得到的 YAML 格式输出（不知道为什么它没有在浏览器中显示）：

---
- !ruby/object:Diff::LCS::ContextChange
  action: "="
  new_element: <p>Paragraph one
  new_position: 0
  old_element: <p>Paragraph one
  old_position: 0
- !ruby/object:Diff::LCS::ContextChange
  action: "!"
  new_element: " Sentence two"
  new_position: 1
  old_element: " Sentence one"
  old_position: 1
- !ruby/object:Diff::LCS::ContextChange
  action: "="
  new_element: |-
    </p>
    <p>Paragraph two
  new_position: 2
  old_element: |-
    </p>
    <p>Paragraph two
  old_position: 2
- !ruby/object:Diff::LCS::ContextChange
  action: "="
  new_element: " Another sentence"
  new_position: 3
  old_element: " Another sentence"
  old_position: 3
- !ruby/object:Diff::LCS::ContextChange
  action: "="
  new_element: |-
    </p>
    <p>Paragraph three
  new_position: 4
  old_element: |-
    </p>
    <p>Paragraph three
  old_position: 4
- !ruby/object:Diff::LCS::ContextChange
  action: "!"
  new_element: " I dare you to update me!</p>"
  new_position: 5
  old_element: " I dare you to change me!</p>"
  old_position: 5
 => nil

超级有用！这将输出一个类似于 wiki 的差异：

sdiff = Diff::LCS.sdiff(seq2, seq1)

diffHTML = ''

sdiff.each do |diff|
  case diff.action
  when '='
    diffHTML << diff.new_element + "."
  when '!'
    # strip_tags only needed on old_element. removes pre-mature end tags.
    diffHTML << "<del>#{diff.old_element.strip_tags}</del> <add>#{diff.new_element}</add>. "
  end
end

@compareBody = diffHTML.html

...[format do block]

然后按照您的意愿设置<del> 和<add> 的样式。如果您正在寻找更简单的东西，diffy 可能就是它，但是一旦您弄清楚了，这将非常灵活。

Answer 2

还有你可以使用的块版本，你可以结合数组解构：

seq1.sdiff(seq2) { |action, (old_pos, old_element), (new_pos, new_element)|
  ...
  puts [action, old_pos, old_element, new_pos, new_element].inspect
  ...
}

seq1.diff(seq2) { |action, position, element| 
  puts [action, position, element].inspect 
}