(j3.2006) Invoking type-bound function using the result of another one

[Tom Clune]

Damian and I have also advocated that the constraints be weakened to somehow allow such chaining of methods.   If there are technical reasons why that particular syntax won?t work, then it seems e could come up with something that is only slightly more verbose.


> On Jan 7, 2016, at 9:59 PM, Van Snyder <Van.Snyder at jpl.nasa.gov> wrote:
> 
> Given:
> 
> Types T1 and T2 with type-bound functions F1 and F2, respectively.
> 
> F1 and F2 have arguments of class T1 and T2 respectively.
> 
> F1 and F2 are also accessible on their own.
> 
> F1 has a result of type T2.
> 
> X1 is a variable of type T1.
> 
> Then I can invoke f2(f1(x1)), but I cannot invoke x1%f1()%f2(), i.e.,
> type-bound function composition is prohibited.
> 
> Other than our traditional aversion to selecting components of function
> results, or more generally to selecting components of expression values,
> was there a technical reason to prohibit this?
> 
> module M
> 
>  type T1
>  contains
>    procedure :: F1
>  end type T1
> 
>  type T2
>  contains
>    procedure :: F2
>  end type T2
> 
> contains
> 
>  type(t2) function F1 ( A )
>    class(t1), intent(in) :: A
>    ...
>  end funciton F1
> 
>  real function F2 ( A )
>    class(t2), intent(in) :: A
>    ...
>  end function H2
> 
> end module M
> 
> program P
> 
>  use M
>  type(t1) :: X1
>  print *, f2(f1(x1))
> ! print *, x1%f1()%f2()        ! Prohibited (why?)
> 
> end program P
> 
> 
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Thomas Clune, Ph. D. 	<Thomas.L.Clune at nasa.gov>
Software Infrastructure Team Lead
Global Modeling and Assimilation Office, Code 610.1
NASA GSFC		
MS 610.1 B33-C128
Greenbelt, MD 20771
301-286-4635













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