UseSWIG: Enable SWIG Fortran target language

6 files changed, 145 insertions, 0 deletions

diff --git a/Help/release/dev/useswig-fortran.rst b/Help/release/dev/useswig-fortran.rst
new file mode 100644
index 0000000..17baf96
--- /dev/null
+++ b/Help/release/dev/useswig-fortran.rst
@@ -0,0 +1,7 @@
+useswig-fortran
+---------------
+
+* The :module:`UseSWIG` module now supports Fortran as a target language if
+  the ``SWIG_EXECUTABLE`` is SWIG-Fortran_.
+
+.. _`SWIG-Fortran`: https://github.com/swig-fortran/swig
diff --git a/Modules/UseSWIG.cmake b/Modules/UseSWIG.cmake
index 78522da..f6a20f8 100644
--- a/Modules/UseSWIG.cmake
+++ b/Modules/UseSWIG.cmake
@@ -341,6 +341,23 @@ function(SWIG_GET_EXTRA_OUTPUT_FILES language outfiles generatedpath infile)
     list(APPEND files "${extra_file}")
   endforeach()
 
+  if (language STREQUAL "FORTRAN" AND CMAKE_Fortran_COMPILER_LOADED)
+    # Process possible user-supplied extension in flags (obtained via parent
+    # scope variable) to determine the source file name.
+    list(FIND SWIG_COMPILATION_FLAGS "-fext" fext_idx)
+    if (fext_idx EQUAL -1)
+      # Default Fortran generated extension
+      set(fext "f90")
+    else()
+      # Get extension from user-provided flag
+      math(EXPR fext_idx "${fext_idx} + 1")
+      list(GET SWIG_COMPILATION_FLAGS "${fext_idx}" fext)
+    endif()
+    set(extra_file "${generatedpath}/${module_basename}.${fext}")
+    set_source_files_properties("${extra_file}" PROPERTIES LANGUAGE "Fortran")
+    list(APPEND files "${extra_file}")
+  endif()
+
   set (${outfiles} ${files} PARENT_SCOPE)
 endfunction()
 
@@ -415,6 +432,7 @@ function(SWIG_ADD_SOURCE_TO_MODULE name outfiles infile)
   get_filename_component(swig_source_file_fullname "${infile}" ABSOLUTE)
 
   if (NOT SWIG_MODULE_${name}_NOPROXY)
+    set(SWIG_COMPILATION_FLAGS ${swig_source_file_flags})
     SWIG_GET_EXTRA_OUTPUT_FILES(${SWIG_MODULE_${name}_LANGUAGE}
       swig_extra_generated_files
       "${outdir}"
@@ -787,6 +805,8 @@ function(SWIG_ADD_LIBRARY name)
     if (APPLE)
       set_target_properties (${target_name} PROPERTIES SUFFIX ".dylib")
     endif ()
+  elseif (swig_lowercase_language STREQUAL "fortran")
+    # Do *not* override the target's library prefix
   else()
     # assume empty prefix because we expect the module to be dynamically loaded
     set_target_properties (${target_name} PROPERTIES PREFIX "")
diff --git a/Tests/UseSWIG/BasicConfiguration.cmake b/Tests/UseSWIG/BasicConfiguration.cmake
index fd3ac40..d054953 100644
--- a/Tests/UseSWIG/BasicConfiguration.cmake
+++ b/Tests/UseSWIG/BasicConfiguration.cmake
@@ -18,6 +18,9 @@ unset(SWIG_LANG_LIBRARIES)
 if(${language} MATCHES csharp)
   set(SWIG_LANG_TYPE TYPE SHARED)
 endif()
+if(${language} MATCHES fortran)
+  set(SWIG_LANG_TYPE TYPE SHARED)
+endif()
 if(${language} MATCHES python)
   find_package(Python REQUIRED COMPONENTS Interpreter Development)
   set(SWIG_LANG_INCLUDE_DIRECTORIES ${Python_INCLUDE_DIRS})
diff --git a/Tests/UseSWIG/BasicFortran/CMakeLists.txt b/Tests/UseSWIG/BasicFortran/CMakeLists.txt
new file mode 100644
index 0000000..e81fb85
--- /dev/null
+++ b/Tests/UseSWIG/BasicFortran/CMakeLists.txt
@@ -0,0 +1,23 @@
+cmake_minimum_required(VERSION 3.12...3.13)
+
+project(TestBasicFortran CXX Fortran)
+
+include(CTest)
+
+set(language "fortran")
+
+include (../BasicConfiguration.cmake)
+get_target_property(EXAMPLE_PREFIX example PREFIX)
+if (NOT EXAMPLE_PREFIX STREQUAL "${CMAKE_SHARED_LIBRARY_PREFIX}"
+    AND NOT EXAMPLE_PREFIX STREQUAL "EXAMPLE_PREFIX-NOTFOUND")
+  message(FATAL_ERROR "Unexpected library prefix on target: got "
+    "'${EXAMPLE_PREFIX}' but expected '${CMAKE_SHARED_LIBRARY_PREFIX}'")
+endif()
+
+
+add_executable(runme ${CMAKE_CURRENT_SOURCE_DIR}/../runme.f90)
+target_link_libraries(runme example)
+set_target_properties(runme PROPERTIES LINKER_LANGUAGE Fortran)
+
+add_test (NAME BasicFortran
+  COMMAND $<TARGET_FILE:runme>)
diff --git a/Tests/UseSWIG/CMakeLists.txt b/Tests/UseSWIG/CMakeLists.txt
index 3cc910f..d102846 100644
--- a/Tests/UseSWIG/CMakeLists.txt
+++ b/Tests/UseSWIG/CMakeLists.txt
@@ -55,6 +55,21 @@ add_test(NAME UseSWIG.BasicPerl COMMAND
   --test-command ${CMAKE_CTEST_COMMAND} -V -C $<CONFIGURATION>
   )
 
+if (CMake_TEST_UseSWIG_Fortran)
+  check_language(Fortran)
+  if (CMAKE_Fortran_COMPILER)
+    add_test(NAME UseSWIG.BasicFortran COMMAND
+      ${CMAKE_CTEST_COMMAND} -C $<CONFIGURATION>
+      --build-and-test
+      "${CMake_SOURCE_DIR}/Tests/UseSWIG/BasicFortran"
+      "${CMake_BINARY_DIR}/Tests/UseSWIG/BasicFortran"
+      ${build_generator_args}
+      --build-project TestBasicFortran
+      --build-options ${build_options}
+      --test-command ${CMAKE_CTEST_COMMAND} -V -C $<CONFIGURATION>
+      )
+  endif()
+endif()
 
 add_test(NAME UseSWIG.MultipleModules COMMAND
   ${CMAKE_CTEST_COMMAND} -C $<CONFIGURATION>
diff --git a/Tests/UseSWIG/runme.f90 b/Tests/UseSWIG/runme.f90
new file mode 100644
index 0000000..1d985d3
--- /dev/null
+++ b/Tests/UseSWIG/runme.f90
@@ -0,0 +1,77 @@
+! File : runme.f90
+program runme
+  use ISO_FORTRAN_ENV
+  implicit none
+  integer, parameter :: STDOUT = OUTPUT_UNIT
+
+  call run()
+contains
+
+subroutine run()
+  use example
+  use iso_c_binding
+  implicit none
+
+  type(Circle)          :: c
+  type(Square), target  :: s ! 'target' allows it to be pointed to
+  class(Shape), pointer :: sh
+  integer(C_INT) :: n_shapes
+
+  ! ----- Object creation -----
+
+  write(STDOUT,*) "Creating some objects"
+  c = Circle(10.0d0)
+  s = Square(10.0d0)
+
+  ! ----- Access a static member -----
+  write(STDOUT,'(a,i2,a)')"A total of", s%get_nshapes(), " shapes were created"
+
+  ! ----- Member data access -----
+
+  ! Notice how we can do this using functions specific to
+  ! the 'Circle' class.
+  call c%set_x(20.0d0)
+  call c%set_y(30.0d0)
+
+  ! Now use the same functions in the base class
+  sh => s
+  call sh%set_x(-10.0d0)
+  call sh%set_y(  5.0d0)
+
+  write(STDOUT,*)"Here is their current position:"
+  write(STDOUT,'(a,f5.1,a,f5.1,a)')"  Circle = (", c%get_x(), ",", c%get_y(), " )"
+  write(STDOUT,'(a,f5.1,a,f5.1,a)')"  Square = (", s%get_x(), ",", s%get_y(), " )"
+
+  ! ----- Call some methods -----
+
+  write(STDOUT,*)"Here are some properties of the shapes:"
+  call print_shape(c)
+  call print_shape(s)
+
+  ! ----- Delete everything -----
+
+  ! Note: this invokes the virtual destructor
+  call c%release()
+  call s%release()
+
+  n_shapes = c%get_nshapes()
+  write(STDOUT,*) n_shapes, "shapes remain"
+  if (n_shapes /= 0) then
+    write(STDOUT,*) "Shapes were not freed properly!"
+    stop 1
+  endif
+
+  write(STDOUT,*) "Goodbye"
+end subroutine
+
+subroutine print_shape(s)
+  use example, only : Shape
+  use iso_c_binding
+  implicit none
+  class(Shape), intent(in) :: s
+
+  write(STDOUT,*)"    area      = ",s%area()
+  write(STDOUT,*)"    perimeter = ",s%perimeter()
+end subroutine
+
+end program