TL;DR: 我正在尝试创建一个外部接口，但是我遇到了编译错误 . 我的F＃技能还不等于任务 .
我写了一个Photoshop脚本，现在我正在尝试将该脚本转换为Fable（F＃），用于我自己的F＃练习 .
旁注：我对F＃很新，但我有一个很好的C＃背景 .
要使用photoshop脚本库，我需要将其定义为外部接口（http://fable.io/docs/interacting.html） . 我试图首先实现一个小类用于测试目的 . 即UnitValue类（参见https://wwwimages.adobe.com/content/dam/Adobe/en/products/indesign/pdfs/JavaScriptToolsGuide_CS5.pdf p.230）
我的尝试：
#r "node_modules/fable-core/Fable.Core.dll"
open System
open Fable.Core
[<Global>]
module Photoshop =
[<Erase;StringEnum>]
type PSUnit =
| [<CompiledName("in")>] Inches
| [<CompiledName("ft")>] Feet
| [<CompiledName("yd")>] Yards
| [<CompiledName("mi")>] Miles
| [<CompiledName("mm")>] Millimeters
| [<CompiledName("cm")>] Centimeters
| [<CompiledName("m")>] Meters
| [<CompiledName("km")>] Kilometers
| [<CompiledName("pt")>] Points
| [<CompiledName("pc")>] Picas
| [<CompiledName("tpt")>] TraditionalPoints
| [<CompiledName("tpc")>] TraditionalPicas
| [<CompiledName("ci")>] Ciceros
| [<CompiledName("px")>] Pixels
| [<CompiledName("%")>] Percent
type PSUnitValue =
abstract ``as``: PSUnit -> float
abstract ``value``: float with get, set
abstract ``type``: PSUnit with get, set
let UnitValue : PSUnitValue = jsNative
open Photoshop
let test = new UnitValue();
test.``value`` = 12.0;
test.``type`` = Unit.Centimeters
Console.WriteLine (test.``as`` PSUnit.Millimeters)
在编译期间，我得到：
C:\PsScripts>fable test.fsx
fable-compiler 0.7.28: Start compilation...
F# project contains errors:
C:\PsScripts\test.fsx(L35,15) : error FSHARP: The type 'UnitValue' is not defined
C:\PsScripts\test.fsx(L36,0) : error FSHARP: Lookup on object of indeterminate type based on information prior to this program point. A type annotation may be needed prior to this program point to constrain the type of the object. This may allow the lookup to be resolved.
C:\PsScripts\test.fsx(L37,0) : error FSHARP: Lookup on object of indeterminate type based on information prior to this program point. A type annotation may be needed prior to this program point to constrain the type of the object. This may allow the lookup to be resolved.
C:\PsScripts\test.fsx(L37,21) : error FSHARP: The field, constructor or member 'Centimeters' is not defined
C:\PsScripts\test.fsx(L39,19) : error FSHARP: Lookup on object of indeterminate type based on information prior to this program point. A type annotation may be needed prior to this program point to constrain the type of the object. This may allow the lookup to be resolved.
C:\PsScripts\test.fsx(L39,0) : error FSHARP: A unique overload for method 'WriteLine' could not be determined based on type information prior to this program point. A type annotation may be needed. Candidates: Console.WriteLine(buffer: char []) : unit, Console.WriteLine(format: string, [<ParamArray>] arg: obj []) : unit, Console.WriteLine(value: bool) : unit, Console.WriteLine(value: char) : unit, Console.WriteLine(value: decimal) : unit, Console.WriteLine(value: float) : unit, Console.WriteLine(value: float32) : unit, Console.WriteLine(value: int) : unit, Console.WriteLine(value: int64) : unit, Console.WriteLine(value: obj) : unit, Console.WriteLine(value: string) : unit, Console.WriteLine(value: uint32) : unit, Console.WriteLine(value: uint64) : unit
我的预期输出将是这样的：
var test = new UnitValue();
test.value = 12;
test.unit = "cm";
console.log(test.as("mm"));
对于那些想知道 UnitValue 类看起来如何并且不想在pdf中查找的人，我在这里用C＃定义它：
public class UnitValue
{
// Static baseUnit not yet implemented in Fable
public static UnitValue baseUnit { get; set; }
// Constructors not yet implemented in Fable
public UnitValue(float value, string unit) { }
public UnitValue(string valueUnit) { }
public string type { get; set; }
public float value { get; set; }
public float @as(string unit) { throw new NotImplementedException(); }
// I don't use convert in my scripts, so not yet implemented in Fable as well
public UnitValue convert(string unit) { throw new NotImplementedException(); }
}
2 回答
您正在绑定变量
UnitValue，而不是声明类型的别名（不确定这是否是意图） .类型和值，就像在C＃中具有不同的范围一样，因此就编译器而言，未声明类型 .
jsNative只是"throw"的简写，它适用于导入的JS结构，但您没有导入任何 . 见http://fable.io/docs/interacting.html因为JS缺少类型，如果interop是意图，你实际上必须自己定义F＃中的类型 .
如果interop不是一个意图，那么写一个普通的F＃代码，没有任何Fable属性，寓言将照顾其余的 .
在此处添加注释答案以进行格式化：UnitValue需要是一个函数（构造函数）：
然后你可以称之为：
还要检查this post以获取有关绑定的一些背景信息 .
在Eugene Tolmachev的帮助下：
工作（ish）代码：
Output
我不知道
export关键字在这里做了什么，或者为什么UnitValue没有new关键字，但它编译并朝着我想要的方向看....向前！
我现在在输出中有
new关键字：现在用法是：