Fortran Wiki PreForM.py

PreForM.py is a pre-processor for modern Fortran projects, written in Python.

Homepage: https://github.com/szaghi/PreForM

PreForM.py supports the most used cpp pre-processing directives and provides advanced features typical of templating systems.

As a matter of fact, many Fortran developers use cpp, the C pre-processor, being one of the most diffused and standardised pre-processor. cpp is a great pre-processor, but it is basically a macro processor, meaning that it is quite focused on macro expansion/substitution/evaluation. cpp has some limitations that makes complex using it as a template system. Let us suppose we want to write a generic interface as the following:

...
interface foo
module procedure foo1
module procedure foo2
module procedure foo3
endinterface
contains
function foo1(in) result(out)
type(first), intent(IN):: in
logical:: out
out = in%logical_test()
endfunction foo1

function foo2(in) result(out)
type(second), intent(IN):: in
logical:: out
out = in%logical_test()
endfunction foo2

function foo3(in) result(out)
type(third), intent(IN):: in
logical:: out
out = in%logical_test()
endfunction foo3
...

Writing a macro in cpp syntax to generalize such a generic interface implementation is quite impossible. On the contrary, using PreForM.py as a template system the implementation becomes very simple and elegant:

...
interface foo
#PFM for i in [1,2,3]:
module procedure foo$i #PFM endfor endinterface contains #PFM for i in [1,2,3] and t in [first,second,third]: function foo$i(in) result(out)
type($t), intent(IN):: in logical:: out out = in%logical_test() endfunction foo$i
#PFM endfor
...

PreForM.py is just a pre-processor for Fortran poor-men supporting the most used cpp directives, but overtaking some of the cpp limitations in order to make PreForM.py similar to a template system using directly the power of Python syntax.

Even if PreForM.py is currently Fortran-agnostic (it being usable within any programming languages) it is focused on Fortran programming language.