F#如何将代码引用编译为程序集

Question

我想知道是否有办法将代码引用编译成程序集？

我了解可以调用CompileUntyped()或 Compile()在 Exp<_>对象，例如:

let x = <@ 1 * 2 @>
let com = x.Compile()

但是，我怎样才能坚持 com磁盘作为一个组件？

谢谢。

Answer 1

您可以使用模式匹配评估 F# 代码报价:

open Microsoft.FSharp.Quotations.Patterns

let rec eval  = function
    | Value(v,t) -> v
    | Call(None,mi,args) -> mi.Invoke(null, evalAll args)
    | arg -> raise <| System.NotSupportedException(arg.ToString())
and evalAll args = [|for arg in args -> eval arg|]

let x = eval <@ 1 * 3 @>

见 F# PowerPack , Unquote , Foq OSS项目或者这个 snippet以获得更完整的实现。

要编译 F# 代码报价，您可以 define a dynamic method使用 Reflection.Emit :

open System.Reflection.Emit

let rec generate (il:ILGenerator) = function
    | Value(v,t) when t = typeof<int> ->
        il.Emit(OpCodes.Ldc_I4, v :?> int)
    | Call(None,mi,args) -> 
        generateAll il args
        il.EmitCall(OpCodes.Call, mi, null)
    | arg -> raise <| System.NotSupportedException(arg.ToString())
and generateAll il args = for arg in args do generate il arg

type Marker = interface end

let compile quotation =
    let f = DynamicMethod("f", typeof<int>, [||], typeof<Marker>.Module)
    let il = f.GetILGenerator()
    quotation |> generate il
    il.Emit(OpCodes.Ret)
    fun () -> f.Invoke(null,[||]) :?> int

let f = compile <@ 1 + 3 @>
let x = f ()

要再次编译为程序集，请使用 Reflection.Emit 使用方法生成类型:

open System
open System.Reflection

let createAssembly quotation =
    let name = "GeneratedAssembly"
    let domain = AppDomain.CurrentDomain
    let assembly = domain.DefineDynamicAssembly(AssemblyName(name), AssemblyBuilderAccess.RunAndSave)
    let dm = assembly.DefineDynamicModule(name+".dll")
    let t = dm.DefineType("Type", TypeAttributes.Public ||| TypeAttributes.Class)
    let mb = t.DefineMethod("f", MethodAttributes.Public, typeof<int>, [||])
    let il = mb.GetILGenerator()
    quotation |> generate il
    il.Emit(OpCodes.Ret)
    assembly.Save("GeneratedAssembly.dll")

createAssembly <@ 1 + 1 @>

见 Fil项目(F# 到 IL)以获得更完整的实现。