rules_fortran

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Basic ​

Source: examples/basic/

1.A. Hello World ​

basic/
├── BUILD.bazel
└── hello.f90
fortran
program hello
    implicit none
    print *, "Hello from Fortran with rules_fortran!"
end program hello
starlark
load("@rules_fortran//fortran:defs.bzl", "fortran_binary")

fortran_binary(
    name = "hello",
    srcs = ["hello.f90"],
)
bash
bazel run //basic:hello
Hello from Fortran with rules_fortran!

1.B. Binary with Dependency ​

basic/
├── BUILD.bazel
├── main.f90
└── math.f90
fortran
! math.f90
module math
    implicit none
contains
    function square(x) result(y)
        real, intent(in) :: x
        real :: y
        y = x * x
    end function square
end module math
fortran
! main.f90
program main
    use math
    implicit none
    print *, "5^2 =", square(5.0)
end program main
starlark
fortran_library(
    name = "math",
    srcs = ["math.f90"],
)

fortran_binary(
    name = "main",
    srcs = ["main.f90"],
    deps = [":math"],
)
bash
bazel run //basic:main
5^2 = 25.0

1.C. Include Files ​

basic/
├── BUILD.bazel
├── include/
│   └── constants.inc
└── use_include.f90
fortran
! Common constants shared via INCLUDE
REAL, PARAMETER :: PI = 3.14159265358979
REAL, PARAMETER :: E = 2.71828182845905
INTEGER, PARAMETER :: MAX_ITERATIONS = 1000
fortran
program use_include
    implicit none
    INCLUDE 'constants.inc'

    print *, "PI =", PI
    print *, "E =", E
    print *, "MAX_ITERATIONS =", MAX_ITERATIONS

    ! Verify values are correct
    if (abs(PI - 3.14159265358979) > 0.0001) stop 1
    if (abs(E - 2.71828182845905) > 0.0001) stop 1
    if (MAX_ITERATIONS /= 1000) stop 1

    print *, "PASSED"
end program use_include
starlark
fortran_binary(
    name = "constants",
    srcs = ["use_include.f90"],
    hdrs = ["include/constants.inc"],
    includes = ["include"],
)
bash
bazel run //basic:constants
PI = 3.1415927
E = 2.7182817
MAX_ITERATIONS = 1000
PASSED