Private variables

[dkfellows]

This PR is about making sPyNNaker's internal fields of objects be actually private, as much as possible. (I've not done anything about SpiNNFrontEndCommon, and I don't plan to do so either.) There will soon be a matching PR for sPyNNaker8.

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A field or method is private when its name starts with __ (double underscore) but doesn't end with more than one _ (i.e., single underscore). Python implements “private” by rewriting the name to have the class name prepended. For example, in this class:

class Foo(object):
    __slots__ = ["__bar"]

    def __init__(self):
        self.__bar = "grill"

The name of the field in instances of Foo is actually _Foo__bar but you're supposed to ignore that and pretend that the variable is truly private. (There's only one place in our codebase where we really need to take advantage of that knowledge.)

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The main awkward bit is that some fields have to remain with a single leading underscore (which is protected by convention) because they're used by subclasses, for equality checks, or for our unit test code. Can't be helped really, I guess…

[coveralls]

Pull Request Test Coverage Report for Build 4872

• 473 of 1707 (27.71%) changed or added relevant lines in 109 files are covered.
• 53 unchanged lines in 26 files lost coverage.
• Overall coverage increased (+0.1%) to 52.011%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
spynnaker/pyNN/models/neural_projections/connectors/one_to_one_connector.py	2	3	66.67%
spynnaker/pyNN/models/neural_projections/synapse_information.py	12	13	92.31%
spynnaker/pyNN/models/neural_properties/neural_parameter.py	31	32	96.88%
spynnaker/pyNN/models/neuron/implementations/abstract_standard_neuron_component.py	4	5	80.0%
spynnaker/pyNN/models/neuron/implementations/struct.py	2	3	66.67%
spynnaker/pyNN/protocols/munich_io_spinnaker_link_protocol.py	12	13	92.31%
spynnaker/pyNN/external_devices_models/threshold_type_multicast_device_control.py	1	3	33.33%
spynnaker/pyNN/models/neural_projections/connectors/all_to_all_connector.py	4	6	66.67%
spynnaker/pyNN/models/neural_projections/delayed_machine_edge.py	0	2	0.0%
spynnaker/pyNN/models/neural_projections/projection_application_edge.py	8	10	80.0%

Files with Coverage Reduction	New Missed Lines	%
spynnaker/pyNN/models/neuron/synapse_dynamics/synapse_dynamics_structural_static.py	1	36.84%
spynnaker/pyNN/utilities/running_stats.py	1	27.78%
spynnaker/pyNN/external_devices_models/external_device_lif_control_vertex.py	1	53.33%
spynnaker/pyNN/external_devices_models/push_bot/push_bot_ethernet/push_bot_wifi_connection.py	1	31.17%
spynnaker/pyNN/models/neural_projections/connectors/from_list_connector.py	1	72.61%
spynnaker/pyNN/models/neuron/synapse_types/synapse_type_alpha.py	1	45.57%
spynnaker/pyNN/connections/ethernet_control_connection.py	1	35.29%
spynnaker/pyNN/spynnaker_external_device_plugin_manager.py	1	38.1%
spynnaker/pyNN/models/neuron/implementations/neuron_impl_standard.py	1	51.58%
spynnaker/pyNN/models/neuron/synapse_dynamics/synapse_dynamics_static.py	1	68.75%

Totals
Change from base Build 4854:	0.1%
Covered Lines:	5135
Relevant Lines:	9873

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💛 - Coveralls