Support "var = value", "value = var", and "var = var"
Fall back the '=' to comparsion when both operators are defined
Correctly support variable shadowing with "var := value"
Also, remove the unused Variable struct
Signed-off-by: Ming-Wei Shih <mishih@microsoft.com>
Only scalars, composites and comprehensions containing scalars are supported.
This will be changed as OPA fixes bug with default values
Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>
