Re: [open-cobol-list] Fortran and Cobol type systems

[Brian Tiffin]

Patrick wrote:
> Hi Everyone
>
> There are some things I miss from Ada when I program in Cobol. Ada has
> facilities to match Ada and Cobol types through their interfaces.cobol
> package and I can use Ada but there are some things I don't like about
> Ada too.
>
> Now I am thinking that the strong typing and user defined types from
> Fortran will be enough for me.
>
> It looks like Fortran strings are padded right with spaces and that is
> encouraging. Does anyone know if the numeric and non-numeric type
> systems match well ?

Kinda.  It's not perfect, but as both COBOL and Fortran can speak 
'native' they can interoperate.  Especially gfortran and cobc.

CHARACTER data and PIC X are pretty close, as is INTEGER and REAL. You'd 
have to write code to deal with COMPLEX and assume a LOGICAL is an 
integer.   Specialty cases would be a pain.  KIND support in Fortran 95 
would be tricky, as would PACKED DECIMAL from the COBOL side (along with 
all the PICTURE variants).

One huge phrase of caution.  Row major and column major ordered arrays.

Fortran will lay down arr[0][0] then arr[1][0] then arr[2][0], row major
C and COBOL lay down arr[0][0], arr[0][1], arr[0][2], column major order.

That means an index swap or transform for tables that you may want to 
pass back and forth to Fortran.  For example, a matrix of integers 
passed to a Fortran formula, COBOL would have val[3][4] and Fortran 
would pull element [4][3] in the indexed assembler instructions.  Comes 
down to "times r, plus c", or "plus r times c".
> Brian has a neat Fortran-Cobol example on his site but it does not use
> an extensive set of types and I haven't been able to come up with much
> otherwise.

I'll try and duff over that listing with more details.  I'd like to 
highlight
the risks with the row-column major indexing.  And some ways of
handling the transforms and/or index swaps.

And some more datatype tests.

Cheers,
Brian

> Thanks for reading-Patrick
>
>
>
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