看似琐碎的阶级示例不会编译

Question

我正在尝试配置特定类型的属性，并保证不要使用getters零。这对于String或URI实例变量正常工作，但是，当尝试使用HTTP::Client进行相同的操作时，编译器会出现一个错误，即在所有初始化方法中并未初始化实例变量。

require "http/client"
class Server
  getter uri : URI
  getter foo : String
  getter connnection : HTTP::Client
  def initialize(@uri)
    @foo = "Bar"
    @connection = HTTP::Client.new @uri
  end
end

编译器给出的完整错误是：

Error in src/server.cr:6: expanding macro
  getter connnection : HTTP::Client
  ^
in macro 'getter' expanded macro: macro_4613328608:113, line 4:
   1.       
   2.         
   3.           
>  4.             @connnection : HTTP::Client
   5. 
   6.             def connnection : HTTP::Client
   7.               @connnection
   8.             end
   9.           
  10.         
  11.       
  12.     
instance variable '@connnection' of Server was not initialized directly in all of the 'initialize' methods, rendering it nilable. Indirect initialization is not supported.

如何适当地初始化 @connection实例变量，以使水晶编译器快乐？

Answer 1

您在那里有错字：

require "http/client"
class Server
  getter uri : URI
  getter foo : String
  getter connnection : HTTP::Client
  #          ^
  def initialize(@uri)
    @foo = "Bar"
    @connection = HTTP::Client.new @uri
  end
end

Answer 2

这对我有用。正如上面指出的那样，您有一个错别字，因此甚至可能不需要允许它。

require "http/client" 
class Server 
  getter uri : URI 
  getter foo : String 
  getter connection : HTTP::Client? 
  def initialize(@uri) 
    @foo = "Bar" 
    @connection = HTTP::Client.new @uri 
  end 
end 
Server.new(URI.parse("https://www.google.com"))