Added submodules demonstrator to demos/fortran.

Its only built if gfortran is used at least with version 6.

demos/fortran/submodules/container.f90

@@ -0,0 +1,13 @@
+submodule (parent) container
+  implicit none
+
+contains
+
+    module function parent_weight(p) result(w)
+      type(parent_type), intent(in) :: p
+      real :: w
+
+      w = p%mother**2 + p%father**2
+    end function parent_weight
+
+end submodule container

demos/fortran/submodules/helper.f90

@@ -0,0 +1,13 @@
+submodule (parent:container) helper
+  implicit none
+
+contains
+
+  module function parent_distance(pa, pb) result(dist)
+    type(parent_type), intent(in) :: pa, pb
+    real :: dist
+
+    dist = sqrt(parent_weight(pa) + parent_weight(pb))
+  end function parent_distance
+
+end submodule helper

demos/fortran/submodules/parent.f90

@@ -0,0 +1,21 @@
+module parent
+  implicit none
+
+  type parent_type
+    real :: mother
+    real :: father
+  end type parent_type
+
+  interface
+    module function parent_weight(p) result(w)
+      type(parent_type), intent(in) :: p
+      real :: w
+    end function parent_weight
+
+    module function parent_distance(pa, pb) result(dist)
+      type(parent_type), intent(in) :: pa, pb
+      real :: dist
+    end function parent_distance
+  end interface
+
+end module parent

demos/fortran/submodules/wscript

@@ -0,0 +1,20 @@
+#! /usr/bin/env python
+
+top = '.'
+out = 'build'
+
+def options(opt):
+	opt.load('compiler_c')
+	opt.load('compiler_fc')
+
+def configure(conf):
+	conf.load('compiler_c')
+	conf.load('compiler_fc')
+
+def build(bld):
+
+	bld(
+		features = 'fc fcshlib',
+		source = 'parent.f90 container.f90 helper.f90',
+		target = 'fudge',
+	)

demos/fortran/wscript

@@ -78,3 +78,5 @@ def build(bld):
 		target = 'mod/two_mods')
 
 	bld.recurse('typemap')
+	if bld.env.FC_NAME == 'GFORTRAN' and int(bld.env.FC_VERSION[0]) >= 6:
+		bld.recurse('submodules')