From Nov. 6th 2018, through OAL tool module established PR. This tool has been integrated into SkyWalking main repostory.
Observability Analysis Language(OAL) Tool is a code generation tool for SkyWalking. This tool starts at SkyWalking v6, which provides the customization feature in aggregation.
If you want to know more about OAL, please see SkyWalking 6 official documents.
INTEGRATED IN MAIN REPOSITORY