Example usage as a tool

Example command-line tool use

The bundled executable fortran-src exposes tools for working with Fortran source code, including inspecting analysis results (such as the program basic blocks or inferred variable and function types) and code reformatting.

In the following examples, the file main.f90 is a Fortran 90-compatible program with the following content:

program main
    implicit none

    real :: r, area
    r = 1.0
    area = area_of_circle(r)
    print *, area

    contains

    function area_of_circle(r) result(area)
        real, parameter :: pi = 3.14
        real, intent(in) :: r
        real :: area
        area = r * r * pi
    end function
end program

The fortran-src binary must be on your system path in order to invoke it. Alternatively, if you use Stack to build the project, you may replace the fortran-src prefix with stack run -- and invoke it directly in the project directory.

Invocations follow the common syntax fortran-src <FILE> <OPTIONS>. You select the command you wish to run using the relevant option. Run fortran-src --help to view a built-in description of the options available.

The extension of the input file determines which Fortran version the file is parsed as. This may be overriden by explicitly requesting a specific version:

fortran-src main.f90 --fortranVersion=90 <COMMAND>

Running fortran-src with no arguments displays the included help, which includes an enumeration of the Fortran versions supported.

Parse a file and view the typechecker output: fortran-src main.f90 --typecheck

4:12     r              Real 4 Variable
4:15     area           Real 4 Variable
11:4     area_of_circle          - Function
12:27    pi             Real 4 Parameter
13:28    r              Real 4 Variable
14:16    area           Real 4 Variable

A file can be parsed and then pretty-printed back using the fortran-src printing algorithm: fortran-src main.f90 --reprint

program main
  implicit none
  real :: r, area
  r = 1.0e0
  area = area_of_circle(r)
  print *, area

  contains

  function area_of_circle(r) result(area)
    real, parameter :: pi = 3.14e0
    real, intent(in) :: r
    real :: area
    area = ((r * r) * pi)
  end function area_of_circle
end program main

Note the printing functionality has added the additional information of the program unit name on the end lines here.

Fortran code is printed with its corresponding source form i.e. FORTRAN 77 code is printed using fixed source form, while Fortran 90 and above use free source form.