F#泛型函数 [英] F# Generic Function

问题描述

在从网络对象到管道

我了解到我可以做到这一点:

let jsonDeserialize json = JsonConvert.DeserializeObject<Dictionary<System.String, System.String>>(json)

然后将序列化的Json键/值对通过管道传输到jsonDeserialize中.它运作良好.我的下一个问题是我可以泛化对JsonConvert.DeserializeObject的调用吗?我想使用它，以便可以将具有相同功能的其他类型反序列化.

我尝试了

let jsonDeserialize json mytype : 'a  = JsonConvert.DeserializeObject<'a>(json)

，但后来却不知道如何使用它.给定一个序列化的JSON字符串，我想

let jsDeser = 
    jsonSerialized
    |> jsonDeserialize Dictionary<string, string>

或类似的东西，在惯用的F#中

解决方案

在F#中，指定类型参数并在尖括号中传递:

let jsonSerialize<'mytype> json : 'mytype = JsonConvert.DeserializeObject<'mytype> json

let jsDeser = jsonSerialized |> jsonDeserialize<Dictionary<string, string>>

或者最好不要指定它们，而让编译器从上下文中找出它们:

let jsonSerialize json = JsonConvert.DeserializeObject<'a> json

let jsDeser : Dictionary<string, string> = jsonDeserialize jsonSerialized

注意:您必须在JsonConvert.DeserializeObject上指定通用参数，因为它具有非通用重载，如果您不指定任何内容，则会选择该重载.

in piping to/from net objects

I learned that I could do this:

let jsonDeserialize json = JsonConvert.DeserializeObject<Dictionary<System.String, System.String>>(json)

then pipe serialized Json Key/Value pairs into jsonDeserialize. It works well. My next question is can I genericize the call to JsonConvert.DeserializeObject? I want to use this so that I can deserialize to other types with the same function.

I tried

let jsonDeserialize json mytype : 'a  = JsonConvert.DeserializeObject<'a>(json)

but then couldn't figure out how to use it. Given a serialized JSON string I want to

let jsDeser = 
    jsonSerialized
    |> jsonDeserialize Dictionary<string, string>

or something like it, in idiomatic F#

解决方案

In F#, type arguments are specified and passed in angle brackets:

let jsonSerialize<'mytype> json : 'mytype = JsonConvert.DeserializeObject<'mytype> json

let jsDeser = jsonSerialized |> jsonDeserialize<Dictionary<string, string>>

Or, preferably, one doesn't specify them at all, but lets the compiler figure them out from the context:

let jsonSerialize json = JsonConvert.DeserializeObject<'a> json

let jsDeser : Dictionary<string, string> = jsonDeserialize jsonSerialized

NOTE: you have to specify the generic argument on JsonConvert.DeserializeObject, because it has a non-generic overload, which will be selected if you don't specify anything.

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