Fortran 77 [F77] : Code in external file without subroutine?

[Hepth]

I have some F77 code and I am wondering if it is possible to inject external code into a separate file and call it without it being a subroutine, and placed into the code. An example would be :

a = 1 + 1
b = a + 1
c = b + a
a = c + b
d = 4 + a


and I want to take lines 3 and 4 and put them into somewhere else, say another file so I have

a = 1 + 1
b = a + 1
(externalfile.f)
d = 4 + a

and it has the same result.

So basically just HIDING code into another file, such that it will be evaluated inline without using a procedure or function call to it. It just uses the local variables that are in use.


The reason I do this is that I have a LOT of variables for a few results, and I am using the FortranForm from Mathematica. But it would be MUCH easier to automate this for changes if I can just export the code to a file and never really look at it, and then my main file wouldn't be ugly.

I really really want to avoid passing all these variables to another function.

 

[AlephZero]

Standard fortran 77 has an INCLUDE statement:

INCLUDE 'filename'

Most fortran 77 compilers have an option to use the C preprocessor (which can do more than just #include, of course).

I've no idea how this relates to Mathematica.

 

[Hepth]

Thanks, for some reason I couldn't find that by searching what I wanted. Thats exactly it.

 

[jtbell]

Note that every time you change the "included" file, you have to recompile the program.

 

[LudusRex]

Yes, it is possible to inject external code into a separate file and call it without it being a subroutine in Fortran 77. This can be achieved by using the INCLUDE statement.

The INCLUDE statement allows you to insert code from another file into your main code without using a subroutine or function. This can help in organizing your code and making it easier to manage.

For example, in your code, you can add the following line after line 2:

INCLUDE 'externalfile.f'

This will insert the code from the file 'externalfile.f' into your main code at that point. The code in the external file will be evaluated inline and will use the local variables that are in use.

However, it is important to note that using the INCLUDE statement can have an impact on the performance of your code. It is recommended to use it sparingly and only when necessary.

In conclusion, yes, it is possible to hide code in another file and have it evaluated inline without using a subroutine or function call in Fortran 77. You can use the INCLUDE statement to achieve this. Just make sure to use it carefully and consider its impact on the performance of your code.