gistfile1.sc

# In schevo.entity:Entity...

@extentmethod
@with_selection
@with_label(u'Delete Selected')
def t_delete_selected(self, selection):
    tx = schevo.transaction.Combination([
        entity.t.delete() for entity in selection
        ])

# @with_selection indicates that the method operates on a selection of entities,
# passed in as a single argument that is an iterable.
#
# The method is decorated with an attribute that indicates that it is such
# a method.
#
# The method should return a single object of the type expected by other methods
# with the same prefix.
#
# If you have a 't' method, it must return a single Transaction.  
# Typically this will be a Combination transaction but could be a custom
# transaction, e.g. one that accepted input, then executed a series of
# child transactions that updated selected entities based on that input.
#
# If you have a 'v' method, it must return a single View, e.g. a view that
# summarized information about a set of selected entities.


list(db.Something.t)
# -> ['create']
#
# Listing the 't' namespace of an extent does not show the with_selection
# methods.


list(db.Something.t('with_selection'))
# -> ['delete_selected']
#
# Calling the 't' namespace of an extent with the name of an attribute
# returns a variant of the namespace where iterating over it will return 
# the names of methods where that attribute has been set to True.