为结构提供通用子例程作为其包含过程

Question

在 Fortran 中使用面向对象的结构时，我尝试将通用函数分配给结构，如下所示：

    !>================================================
    type:: PropEq
    !>------------------------------------------------     
        real(dp) :: coeffs(4)      
        contains               
            procedure, pass :: compute => computePhysicalProperty    
    !>------------------------------------------------     
    end type PropEq
    !>================================================

通用子程序接口如下：

    !!>================================================
    interface computePhysicalProperty
    !!>------------------------------------------------ 
        module procedure computePhysicalProperty_scalar 
        module procedure computePhysicalProperty_array
    !!>------------------------------------------------ 
    end interface computePhysicalProperty
    !!>================================================  

还有两个函数：

    !>================================================
    function computePhysicalProperty_scalar(propEq, T) result(value)
    !>------------------------------------------------ 
        real(dp) :: value
        
        class(PropEqAbstract) :: propEq
        real(dp), intent(in) :: T
        real(dp), allocatable :: a(:)
        
        a = propEq% coeffs
        
        value = a(1) + a(2)*T + a(3)*T*T + a(4)*T*T*T

    !>------------------------------------------------  
    end function computePhysicalProperty_scalar
    !>================================================
    
    !>================================================
    function computePhysicalProperty_array(propEq, T) result(value)
    !>------------------------------------------------ 
        real(dp) :: value
        
        class(PropEqAbstract) :: propEq
        real(dp), intent(in), allocatable :: T(:)
        real(dp), allocatable :: a(:)
        
        a = propEq% coeffs
        
        value = a(1) + a(2)*T + a(3)*T*T + a(4)*T*T*T

    !>------------------------------------------------  
    end function computePhysicalProperty_array
    !>================================================

本质上，我试图重载该过程以允许函数输入标量和数组。

这样做时，我收到以下错误：

error #8182: The name is neither an abstract interface nor a procedure with an explicit interface.   [COMPUTEPHYSICALPROPERTY]

此外，我发现以下似乎有效： 带有过程参数的通用类型绑定过程

   !>================================================
    type:: PropEq
    !>------------------------------------------------     
        real(dp) :: coeffs(4)      
        contains               
            procedure, pass :: compute_scalar => computePhysicalProperty_scalar
            procedure, pass :: compute_array => computePhysicalProperty_array
            generic :: compute => compute_scalar, compute_array    
    !>------------------------------------------------     
    end type PropEq
    !>================================================

为什么过程需要在类型中显式声明？

有没有办法使用接口将类型简化为以下？

????? :: compute => computePhysicalProperty

谢谢你

编译器：Intel
IDE：Visual Studio Enterprise

Answer 1

Fortran 语言标准不允许您尝试执行的操作。绑定不能指向通用接口，它必须指向过程。一旦您的类型中拥有了绑定（type=bound procedure），您就可以使用

generic :: compute =>

.

从它们创建通用绑定。

标准语法如下：

R748 type-bound-proc-binding
         is type-bound-procedure-stmt
         or type-bound-generic-stmt
         or final-procedure-stmt

从中你感兴趣

R749 type-bound-procedure-stmt
     is PROCEDURE [ [ , binding-attr-list ] :: ] type-bound-proc-decl-list
     or PROCEDURE (interface-name), binding-attr-list :: binding-name-list

然后

R750 type-bound-proc-decl     is     binding-name [ => procedure-name ]

有约束

C774 (R750) The procedure-name shall be the name of an accessible module procedure or an external procedure
    that has an explicit interface.

这是您所遇到的最终限制。