如何将匿名对象 splattify 以便可以在其上使用 &method？

发布于 2024-12-05 05:05:54 字数 1022 浏览 2 评论 0原文

当 method_name 需要多个对象时，我想使用 &method(:method_name) 习惯用法。我可以在 Ruby 1.9 下执行此操作吗？

例如，如果我的

def move_file(old_filename, new_filename)
  STDERR.puts "Moving #{old_filename.inspect} to #{new_filename.inspect}"
  # Implementation for careful moving goes here
end

old_filenames = ["foo.txt", "bar.txt", "hoge.ja.txt"]
new_filenames = ["foo_20110915.txt", "bar_20110915.txt", "hoge_20110915.ja.txt"]

代码

old_filenames.zip(new_filenames).each(&method(:move_file))

可以在 Ruby 1.8 下运行，但不能在 Ruby 1.9 下运行。在 Ruby 1.9 下，它尝试执行 move_file(["foo.txt", "foo_20110915.txt"]) 而不是 move_file("foo.txt", "foo_20110915.txt")。

我如何将其splattify以使其具有正确的数量？

我知道的解决方法：

将 def move_file(old_filename, new_filename) 替换为 def move_file(*arguments)
替换 each(&method(:move_file)) 与
每个{|旧文件名，新文件名| move_file（旧文件名，新文件名）}

原文

I'm wanting to use the &method(:method_name) idiom when there's more than one object required by method_name. Can I do this under Ruby 1.9?

For example, if I've got

def move_file(old_filename, new_filename)
  STDERR.puts "Moving #{old_filename.inspect} to #{new_filename.inspect}"
  # Implementation for careful moving goes here
end

old_filenames = ["foo.txt", "bar.txt", "hoge.ja.txt"]
new_filenames = ["foo_20110915.txt", "bar_20110915.txt", "hoge_20110915.ja.txt"]

the code

old_filenames.zip(new_filenames).each(&method(:move_file))

works under Ruby 1.8, but not under Ruby 1.9. Under Ruby 1.9, it's trying to do move_file(["foo.txt", "foo_20110915.txt"]) instead of move_file("foo.txt", "foo_20110915.txt").

How do I splattify it so it has the correct arity?

Workarounds I'm aware of:

Replace def move_file(old_filename, new_filename) with def move_file(*arguments)
Replace each(&method(:move_file)) with
each{|old_filename, new_filename| move_file(old_filename, new_filename)}

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涙—继续流 2024-12-12 05:05:54

相反，

each{|old_filename, new_filename| move_file(old_filename, new_filename)}

你应该能够做到

each{|pair| move_file(*pair)}

但我不知道你如何实现无块变体（我也需要它几次）。我猜 &- 简写是为了使语法更简单，并且并不意味着会被太多阻塞（例如，无论是将数组作为数组传递，还是将其展开）。 :)

Instead

each{|old_filename, new_filename| move_file(old_filename, new_filename)}

you should be able to do

each{|pair| move_file(*pair)}

But I don't know how you'd pull off blockless variant (I needed it couple of times as well). I guess &-shorthand was made to make the syntax simpler, and is not meant to be clogged much (whether it will be passed an array as an array, or splatted, for example). :)

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