171 lines
4.8 KiB
Markdown
171 lines
4.8 KiB
Markdown
# ScriptMethod
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- **功能描述：** 把静态函数导出变成第一个参数的成员函数。
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- **使用位置：** UFUNCTION
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- **引擎模块：** Script
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- **元数据类型：** string="a;b;c"
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- **限制类型：** static function
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- **关联项：** [ScriptMethodMutable](ScriptMethodMutable.md), [ScriptMethodSelfReturn](ScriptMethodSelfReturn.md)
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- **常用程度：** ★★★
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把静态函数导出变成第一个参数的成员函数。
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- 把func(A，B)变成A.func(B)，这样就可以给A对象添加成员函数方法。有点像C#里的扩展方法。
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- 也可以直接再提供一个名字来改变包装后的成员函数的名称。注意与ScriptName区分，ScriptName改变的是本身导出到脚本的名字，而ScriptMethod改变的是结果成员函数的名字。把func(A，B)改成A.OtherFunc(B)。
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## 测试代码：
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```cpp
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UCLASS(Blueprintable, BlueprintType)
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class INSIDER_API UMyPython_ScriptMethod :public UObject
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{
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GENERATED_BODY()
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public:
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};
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USTRUCT(BlueprintType)
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struct INSIDER_API FMyPythonStruct_ScriptMethod
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{
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GENERATED_BODY()
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};
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UCLASS(Blueprintable, BlueprintType)
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class INSIDER_API UMyPython_ScriptMethod_Test :public UObject
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{
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GENERATED_BODY()
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public:
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UFUNCTION(BlueprintCallable, meta = (ScriptMethod))
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static void MyFuncOnObject(UMyPython_ScriptMethod* obj, FString val);
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UFUNCTION(BlueprintCallable, meta = (ScriptMethod = "MySuperFuncOnObject;MyOtherFuncOnObject"))
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static void MyFuncOnObject2(UMyPython_ScriptMethod* obj, FString val);
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public:
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UFUNCTION(BlueprintCallable, meta = (ScriptMethod))
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static void MyFuncOnStruct(const FMyPythonStruct_ScriptMethod& myStruct, FString val);;
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};
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```
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## 测试效果：
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可见在MyPythonStruct_ScriptMethod里增加了my_func_on_struct的方法，而MyPython_ScriptMethod里增加了my_func_on_object的方法。因此如果在py里你就可以把这两个函数当作成员函数一样调用。
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另外MyFuncOnObject2上面设置了两个ScriptMethod 别称，也可以在MyPython_ScriptMethod里见到。
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```cpp
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class MyPythonStruct_ScriptMethod(StructBase):
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r"""
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My Python Struct Script Method
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**C++ Source:**
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- **Module**: Insider
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- **File**: MyPython_ScriptMethod.h
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"""
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def __init__(self) -> None:
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...
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def my_func_on_struct(self, val: str) -> None:
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r"""
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x.my_func_on_struct(val) -> None
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My Func on Struct
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Args:
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val (str):
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"""
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...
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class MyPython_ScriptMethod(Object):
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r"""
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My Python Script Method
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**C++ Source:**
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- **Module**: Insider
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- **File**: MyPython_ScriptMethod.h
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"""
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def my_super_func_on_object(self, val: str) -> None:
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r"""
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x.my_super_func_on_object(val) -> None
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My Func on Object 2
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Args:
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val (str):
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"""
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...
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def my_other_func_on_object(self, val: str) -> None:
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r"""
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deprecated: 'my_other_func_on_object' was renamed to 'my_super_func_on_object'.
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"""
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...
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def my_func_on_object(self, val: str) -> None:
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r"""
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x.my_func_on_object(val) -> None
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My Func on Object
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Args:
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val (str):
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"""
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...
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class MyPython_ScriptMethod_Test(Object):
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r"""
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My Python Script Method Test
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**C++ Source:**
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- **Module**: Insider
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- **File**: MyPython_ScriptMethod.h
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"""
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@classmethod
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def my_func_on_struct(cls, my_struct: MyPythonStruct_ScriptMethod, val: str) -> None:
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r"""
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X.my_func_on_struct(my_struct, val) -> None
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My Func on Struct
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Args:
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my_struct (MyPythonStruct_ScriptMethod):
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val (str):
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"""
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...
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@classmethod
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def my_func_on_object2(cls, obj: MyPython_ScriptMethod, val: str) -> None:
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r"""
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X.my_func_on_object2(obj, val) -> None
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My Func on Object 2
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Args:
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obj (MyPython_ScriptMethod):
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val (str):
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"""
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...
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@classmethod
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def my_func_on_object(cls, obj: MyPython_ScriptMethod, val: str) -> None:
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r"""
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X.my_func_on_object(obj, val) -> None
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My Func on Object
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Args:
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obj (MyPython_ScriptMethod):
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val (str):
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"""
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...
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```
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## 原理：
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在GenerateWrappedDynamicMethod中有详细的如何把静态函数包装成成员函数的过程。感兴趣的可以去细看。
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```cpp
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PyTypeObject* FPyWrapperTypeRegistry::GenerateWrappedClassType(const UClass* InClass, FGeneratedWrappedTypeReferences& OutGeneratedWrappedTypeReferences, TSet<FName>& OutDirtyModules, const EPyTypeGenerationFlags InGenerationFlags)
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{
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// Should this function also be hoisted as a struct method or operator?
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if (InFunc->HasMetaData(PyGenUtil::ScriptMethodMetaDataKey))
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{
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GenerateWrappedDynamicMethod(InFunc, GeneratedWrappedMethodCopy);
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}
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}
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```
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