问题
I was wondering if there is something similar to this in Fortran. Of course this example does not compile but I think you can get the idea.
program test
character(1):: sub
sub='A'
call sub
sub='B'
call sub
end program
subroutine A
print*,'OK! A'
end subroutine A
subroutine B
print*,'OK! B'
end subroutine B
回答1:
You cannot accomplish this by setting a character variable, but you can do this with procedure pointers. I've modified your example slightly to implement that. See:
program test
implicit none
abstract interface
subroutine no_args
end subroutine
end interface
procedure(no_args), pointer :: sub => null()
sub => A
call sub
sub => B
call sub
contains
subroutine A
implicit none
print *,"OK! A"
end subroutine
subroutine B
implicit none
print *,"OK! B"
end subroutine
end program
The changes are:
- Define an interface for the procedure pointer
- Declare
subas a procedure pointer to that abstract interface
You can then assign sub to subroutines that take no arguments (since that is the what the interface says) and call them through sub the way you envision.
回答2:
Closest you could get is function/procedure pointers, but that would be fortran-2003. BAsically, given input 'A' or 'B' you set pointer to point to either subroutine A or subroutine B. More details at How to alias a function name in Fortran
来源：https://stackoverflow.com/questions/30308601/the-name-of-a-subroutine-can-be-a-variable-in-fortran