fortiel 0.0.4

Fortiel Compiler / Fortran Preprocessor

fortiel — Fortran preprocessor and metaprogramming engine

Fortiel is a Fortran preprocessor.

Installation

Fortiel can be install as the PyPI package:

pip3 install fortiel

Preprocessor language

Directives

Common directive syntax is:

#fpp <directive> <directiveArguments>

where <directive>_ is one of the known preprocessor directives. Both fpp and <directive> are case-insensitive.

let directive

let directive declares a new named variable.

Syntax:

#fpp let <var> = <expression>

<expression> should be a valid Python 3 expression, that may refer to the previously defined variables, Fortiel builtins and Python 3 builtins.

Functions can be also declared using the let directive.

Syntax:

#fpp let <var>([<argument>[, <anotherArgument>]*]) = <expression>

undef directive

undef directive undefines the names, previously defined with the let directive.

Syntax:

#fpp undef <var>[, <anotherVar>]*

Builtin names like __FILE__ or __LINE__ can not be undefined.

if/else if/else/end if directive

if is a classic conditional directive.

Syntax:

#fpp if <condition>
  ! Fortran code.
#fpp else if <condition>
  ! Fortran code.
#fpp else
  ! Fortran code.
#fpp end if

Note that else if and elseif directives, end if and endif directives are equivalent.

do/end do directive

do directives substitutes the code multiple times.

Syntax:

#fpp do <var> = <first>, <last>[, <step>]
  ! Fortran code.
#fpp end do

<first>, <last> and optional <step> expressions should evaluate to integers. Inside the loop body a special variable __INDEX__ is defined, which is equal to the the current iterator value.

Note that end do and enddo directives are equivalent.

include and use directives

include directive directly includes the contents of the file located at <filePath> into the current source.

Syntax:

#fpp include '<filePath>'
! or
#fpp include "<filePath>"
! or
#fpp include <<filePath>>

use directive is the same as include, but it skips the non-directive lines.

Syntax:

#fpp use <filePath>
! or
#fpp use <filePath>
! or
#fpp use <<filePath>>

line directive

line directive changes current line number and file path.

Syntax:

#fpp [line] <lineNumber> "<filePath>"

In-line substitutions

{} substitution

@: substitution

Examples

Generic programming

module Distances
  
  implicit none
  
  #fpp let NUM_RANKS = 2

  interface computeSquareDistance
  #fpp do rank = 0, NUM_RANKS
    module procedure computeSquareDistance{rank}
  #fpp end do    
  end interface computeSquareDistance

contains

#fpp do rank = 0, NUM_RANKS
  function computeSquareDistance{rank}(n, u, v) result(d)
    integer, intent(in) :: n
    real, intent(in) :: u(@:,:), v(@:,:)
    real :: d
    integer :: i
    d = 0.0
    do i = 1, n
    #fpp if rank == 0
      d = d + (u(i) - v(i))**2
    #fpp else
      d = d + sum((u(@:,i) - v(@:,i))**2)
    #fpp end if
    end do
  end function computeSquareDistance{rank}
#fpp end do    
end module Distances

module Distances
  
  implicit none
  
  interface computeSquareDistance
    module procedure computeSquareDistance0
    module procedure computeSquareDistance1
    module procedure computeSquareDistance2
  end interface computeSquareDistance

contains

  function computeSquareDistance0(n, u, v) result(d)
    integer, intent(in) :: n
    real, intent(in) :: u(:), v(:)
    real :: d
    integer :: i
    d = 0.0
    do i = 1, n
      d = d + (u(i) - v(i))**2
    end do
  end function computeSquareDistance0
  function computeSquareDistance1(n, u, v) result(d)
    integer, intent(in) :: n
    real, intent(in) :: u(:,:), v(:,:)
    real :: d
    integer :: i
    d = 0.0
    do i = 1, n
      d = d + sum((u(:,i) - v(:,i))**2)
    end do
  end function computeSquareDistance1
  function computeSquareDistance2(n, u, v) result(d)
    integer, intent(in) :: n
    real, intent(in) :: u(:,:,:), v(:,:,:)
    real :: d
    integer :: i
    d = 0.0
    do i = 1, n
      d = d + sum((u(:,:,i) - v(:,:,i))**2)
    end do
  end function computeSquareDistance2
end module Distances

Missing features