Add helper to parse single expression
Add helper to parse single expression

Eva-xiaohui-luo/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa,Eva-xiaohui-luo/opa,timothyhinrichs/opa,timothyhinrichs/opa,timothyhinrichs/opa,timothyhinrichs/opa,open-policy-agent/opa,tsandall/opa,timothyhinrichs/opa,tsandall/opa,open-policy-agent/opa,open-policy-agent/opa,Eva-xiaohui-luo/opa,tsandall/opa,tsandall/opa,open-policy-agent/opa,open-policy-agent/opa