I'm not 100% on the change as is. There are a couple things I want to solve here:

• Inserting JSON through a CLI command feels really bad to me. We're very close to just making REST calls with curl at this point. Therefore, I changed the way filters are defined. Instead of accepting JSON, you can specify filters with the format -f 'property=value'. You can also filter into relational properties with a dot-delimited format. E.G. -f nested.property=value. -f can be specified multiple times.
• Since this is an experimentation tool, it should provide a way to convert these commands into real code. There seems to be a need for several features which go beyond this goal: complex arguments, filters, etc. For these cases we can do what we can but at a certain point code will need to be written either in another slcli command or with user-created scripts. To aid in this, the --output-python option was added to call-api. This outputs python code that shows an example of using softlayer-python to make the API call that call-api would have made. For example:

> slcli call-api Account getVirtualGuests \
                                         -f 'virtualGuests.datacenter.name=dal05' \
                                         -f 'virtualGuests.maxCpu=4' \
                                         --mask=id,hostname,datacenter.name,maxCpu test \
                                         --limit=10 \
                                         --output-python
import SoftLayer

client = SoftLayer.create_client_from_env()
result = client.call(u'Account',
                     u'getVirtualGuests',
                     u'test',
                     filter={u'virtualGuests': {u'datacenter': {u'name': {'operation': u'_= dal05'}}, u'maxCpu': {'operation': 4}}},
                     limit=1,
                     mask=u'id,hostname,datacenter.name,maxCpu')