Ruby代码美化，将长指令分割成多行

Question

我们如何编写以下语句以提高可读性？

Promotion.joins(:category).where(["lft>=? and rgt<=?", c.lft, c.rgt]).joins(:shops).where(:promotions_per_shops => { :shop_id => shops_id }).count('id', :distinct => true)

以下代码无法编译

Promotion.joins(:category)
         .where(["lft>=? and rgt<=?", c.lft, c.rgt])
         .joins(:shops)
         .where(:promotions_per_shops => { :shop_id => shops_id })
         .count('id', :distinct => true)

syntax error, unexpected '.', expecting kEND
                     .where(["lft>=? and rgt<=?", c.lft, c.rgt])

- EricLarch

Answer 1

也可以这样做

Promotion.joins(:category) \
         .where(["lft>=? and rgt<=?", c.lft, c.rgt]) \
         .joins(:shops) \
         .where(:promotions_per_shops => { :shop_id => shops_id }) \
         .count('id', :distinct => true)

- EricLarch

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反斜杠这个东西非常有用！谢谢 - Kristiyan Tsvetanov

Answer 2

像这样做：

Promotion.joins(:category).
         where(["lft>=? and rgt<=?", c.lft, c.rgt]).
         joins(:shops).
         where(:promotions_per_shops => { :shop_id => shops_id }).
         count('id', :distinct => true)

- Geo

Answer 3

它应该能够在1.9版本中编译。在之前的版本中确实是无效的。

- Mchl