元帅无法使用默认proc(TypeError)转储哈希

问题描述

我有这个ruby脚本，它会生成一个哈希并将其保存到文件中.

I have this ruby script that generates a hash and saves it to a file.

有时文件不存在或为空，所以我总是首先检查它的存在.然后，我将旧值加载到哈希中，然后尝试再次保存.我已经为此苦了很久了.这是一个示例:

Sometimes the file doesn't exist or is empty, so I always check the existence of it first. Then I load the old values into my hash and try to save again. I've been struggling with this for a long time now. This is a sample:

newAppName = ARGV[0]
newApp = Hash.new
newApp["url"] = ARGV[1]
newApp["ports"] = ARGV[2].to_i

apps = Hash.new { |h, k| h[k] = Hash.new }
# apps["test"] = {"url" => "www.test.com", "ports" => 3 }

appsFile = '/home/test/data/apps'

if File.exists?(appsFile)
  apps = Marshal.load File.read(appsFile)
else
  puts "Inserting first app into list..."
end

apps[newAppName] = newApp

serialisedApps = Marshal.dump(apps) # This line is where I get the error

File.open(appsFile, 'w') {|f| f.write(serialisedApps) }

现在我收到此错误:

script.rb:53:in `dump': can't dump hash with default proc (TypeError)`

是什么意思?我的哈希值错了吗?我该如何解决?

What does it mean? Is my hash wrong? How do I fix it?

尽管我在Mac上进行了测试，并且此脚本在Linux中运行，但我尝试使用irb手动进行操作，并且运行良好.他们的行为不应有所不同，对吧?

I tried doing it manually with irb and it was working fine, though I tested on a Mac and this script is running in Linux. They should not behave different, right?

推荐答案

Ruby没有用于代码的Marshal格式，仅用于数据.您无法封送Proc或lambda.

Ruby doesn't have a Marshal format for code, only for data. You cannot marshal Procs or lambdas.

您的apps哈希具有default_proc，因为

hsh = Hash.new { some_block }

与

hsh = {}
hsh.default_proc = ->{ some_block }

IOW:您的apps哈希包含代码，并且代码无法编组.

IOW: your apps hash contains code, and code cannot marshalled.

这篇关于元帅无法使用默认proc(TypeError)转储哈希的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！