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

[Damian Rouson]

As Tom suggests, I too am very interested in seeing responses to Van's question and I would be excited to see the proposed feature gain support. 


D

Sent from my iPhone

> On Jan 8, 2016, at 5:49 AM, Tom Clune <Thomas.L.Clune at nasa.gov> wrote:
> 
> Apologies for my C++ accent.
> 
> I meant ?chaining of invocations of type-bound procedures?.
> 
>> On Jan 8, 2016, at 8:46 AM, Tom Clune <Thomas.L.Clune at nasa.gov> wrote:
>> 
>> 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
>>> 
>>> 
>>> _______________________________________________
>>> J3 mailing list
>>> J3 at mailman.j3-fortran.org
>>> http://mailman.j3-fortran.org/mailman/listinfo/j3
>> 
>> 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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> 
> 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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> 
> _______________________________________________
> J3 mailing list
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