=== Example 1: hello world (adding command to the interface)

__init__.py file
{{{
## import the required files

import helloworld as helloworld


## Does it define a new interface (will be avaible with ./bin/mg5_aMC --mode=maddm
## Put None if no dedicated command are required
new_interface = helloworld.NewInterface

## Does it define a new output mode. Need to be define
new_output = {}

## The test/code have been validated up to this version
latest_validated_version = '2.3.4'
}}}

helloworld.py file
{{{
class Newinterface(master_interface.MasterCmd):

    def do_helloworld(self, line):
        """print hello world"""
        print "hello world"
}}}

=== Example 2: New Exporter

__init__.py file
{{{
## import the required files

import output as output

## Define a typical error for the plugin
class EVTDECONS_Error(Exception): pass

## Does it define a new interface (will be avaible with ./bin/mg5_aMC --mode=maddm
## Put None if no dedicated command are required
new_interface = False

## Does it define a new output mode. Need to be define
new_output = {'madweight2': output.NEW_MW_OUTPUT,
              'standalone_lib': output.NEW_CPP_LIB}

## The test/code have been validated up to this version
latest_validated_version = '2.3.4'
}}}


output.py file
{{{
import madgraph.iolibs.export_cpp as export_cpp
import madgraph.iolibs.export_v4 as export_v4
import madgraph.various.misc as misc
# Note loop type output are not supported.

class My_MW_Exporter(export_v4.ProcessExporterFortranMWGroup):

    nb_done = 0

    def __init__(self, *args, **opts):
        misc.sprint("Initialise the exporter")
        return super(My_MW_Exporter, self).__init__(*args, **opts)

    def copy_v4template(self, *args, **opts):
        misc.sprint("copy the associate template")
        return super(My_MW_Exporter, self).copy_v4template(*args, **opts)

    def generate_subprocess_directory(self, subproc_group,
                                         fortran_model, me=None):

        misc.sprint(me)
        if me is None:
            MyExporter.nb_done +=1
            current_generated = MyExporter.nb_done
        else:
            current_generated = me

class MY_CPP_Standalone(export_cpp.ProcessExporterPythia8):

    def __init__(self, *args, **opts):
        misc.sprint("Initialise the exporter")
        return super(MY_CPP_Standalone, self).__init__(*args, **opts)

    def setup_cpp_standalone_dir(self, model):

        misc.sprint("initialise the directory")
        return super(MY_CPP_Standalone, self).setup_cpp_standalone_dir(model)


    def generate_subprocess_directory(self, subproc_group,
                                         fortran_model, me=None):

        misc.sprint('create the directory')
        return super(MY_CPP_Standalone, self).generate_subprocess_directory(subproc_group, fortran_model, me)


    def convert_model(self, model, wanted_lorentz=[], wanted_coupling=[]):
        misc.sprint('create the model')
        return super(MY_CPP_Standalone, self).convert_model(model, wanted_lorentz, wanted_coupling)

    def finalize(self, matrix_element, cmdhistory, MG5options, outputflag):
        """typically creating jpeg/HTML output/ compilation/...
           cmdhistory is the list of command used so far.
           MG5options are all the options of the main interface
           outputflags is a list of options provided when doing the output command"""
        misc.sprint("pass here")
        return super(MY_CPP_Standalone, self).finalize(matrix_element, cmdhistory, MG5options, outputflag)

NEW_CPP_LIB = {
    # check status of the directory. Remove it if already exists
    'check': True,
    # Language type: 'v4' for f77/ 'cpp' for C++ output
    'exporter': 'cpp',
    # Output type:
    #[Template/dir/None] copy the Template, just create dir  or do nothing
    'output': 'Template',
    # Decide which type of merging if used [madevent/madweight]
    'group_mode': 'madweight',
    # if no grouping on can decide to merge uu~ and u~u anyway:
    'sa_symmetry': True,
    # The most important part where the exporter is defined:
    # a plugin typically defines this file in another file (here tak one of MG5)
    'exporter_class': MY_CPP_Standalone
    }

NEW_MW_OUTPUT = {
    # check status of the directory. Remove it if already exists
    'check': True,
    # Language type: 'v4' for f77/ 'cpp' for C++ output
    'exporter': 'v4',
    # Output type:
    #[Template/dir/None] copy the Template, just create dir  or do nothing
    'output': 'Template',
    # Decide which type of merging to used [madevent/madweight]
    'group_mode': 'madweight',
    # if no grouping on can decide to merge uu~ and u~u anyway:
    'sa_symmetry': True,
    # The most important part where the exporter is defined:
    # a plugin typically defines this file in another file (here tak one of MG5)
    'exporter_class': My_MW_Exporter
    }
}}}


=== List of function that need to be defined in the exporter For Fortran output:
   
   Note: All of them are defined in ProcessExporterFortran. So you need to define them only if you start a class from scratch.
         This list correspond to the call to the exporter performed outside the class itself.

   1. __init__(self, mgme_dir = "", dir_path = "", opt=None)
   2. copy_v4template(self, modelname)
   3. generate_subprocess_directory(self, subproc_group, helicity_model, me=None) [for grouped]
   4. generate_subprocess_directory(self, matrix_element, helicity_model, me_number) [for ungrouped]
   4. convert_model(model, wanted_lorentz=[], wanted_coupling=[])
   5. finalize(self,matrix_element, cmdhistory, MG5options, outputflag)     
   6. modify_grouping(self, matrix_element)
   7. export_model_files(self, model_v4_path) [only if you want to support old model format]
   8. export_helas(self, HELAS_PATH) [only if you want to support old model format]

=== List of function that need to be defined in the exporter For Cpp output:

   Note: All of them are defined in ProcessExporterCPP. So you need to define them only if you start a class from scratch.
         This list correspond to the call to the exporter performed outside the class itself. 
  
   1. __init__(self, mgme_dir = "", dir_path = "", opt=None)
   2. setup_cpp_standalone_dir(self, model)
   3. generate_subprocess_directory(self, subproc_group, helicity_model, me=None) [for grouped]
   4. generate_subprocess_directory(self, matrix_element, helicity_model, me_number) [for ungrouped]
   4. convert_model(model, wanted_lorentz=[], wanted_coupling=[])
   5. finalize(self,matrix_element, cmdhistory, MG5options, outputflag)     
   6. modify_grouping(self, matrix_element)
   7. make_model_cpp(self, export_dir)

=== List of class variable that need to be defined in the exporter:

   Note: All of them are defined in ProcessExporterFortran/ProcessExporterCPP. So you need to define them only if you start a class from scratch.
         This list correspond to the attribute of the exporter called outside the  exporter class.

   1. grouped_mode # says which type of exporter to use.