Builders That Modify the Target or Source Lists Using an Emitter

       def modify_targets(target, source, env):
           target.append('new_target')
           source.append('new_source')
           return target, source
       bld = Builder(action = 'foobuild $TARGETS - $SOURCES',
                     suffix = '.foo',
                     src_suffix = '.input',
                     emitter = modify_targets)
       env = Environment(BUILDERS = {'Foo' : bld})
       env.Foo('file')
    

      % scons -Q
      foobuild file.foo new_target - file.input new_source
    

       bld = Builder(action = 'my_command',
                     suffix = '.foo',
                     src_suffix = '.input',
                     emitter = 'MY_EMITTER')
       def modify1(target, source, env):
           return target, source
       def modify2(target, source, env):
           return target, source
       env1 = Environment(BUILDERS = {'Foo' : bld},
                          MY_EMITTER = modify1)
       env2 = Environment(BUILDERS = {'Foo' : bld},
                          MY_EMITTER = modify2)
       env1.Foo('file1')
       env2.Foo('file2')