How to reference the current entry via twig in the control panel? I'm trying to write a general use plugin for a calculation fieldtype that evaluates a twig expression (defined in the field settings) to display additional information about the current record in the CP (i.e. price * qty = amount). So far, everything is working perfectly — the generic expression 1 + 1 is evaluated and the result is properly displayed in the field.

The problem is, I don't actually know how to reference the current entry in the CP from within the CP via twig, to get access to the entry field values. Looking for something like {{ entry.price }} * {{ entry.qty }}, but don't know what to use instead of entry. Does anyone know a twig expression that I can use?
As far as I know. The variable {{ entry }} is not available to custom field plugins through inheritance and must be explicitly set and returned as a variable in the getInputHtml method within the class definition file. 

See this question for details on how to set this variable and things to be aware of.