[TAJO-409] Add explored and explained annotations to Tajo function system

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.8.0
• Component/s: Function/UDF
• Assignee: SeongHwa Ahn
• Reporter: Hyunsik Choi
• Created: 11/Dec/13 05:45
• Updated: 20/Jan/14 04:35
• Resolved: 20/Jan/14 04:30

Description

Currently, it is hard for developers to add explanations to functions and user-defined functions. Java has annotation feature. We can make function system more explored and explained with java annotations.

Proposal

A function should have the following annotations

• function name (string) - optional
  • If a function is user-defined, this field is ignored.
  • the function name of user-defined function is given when it is registered.
• synonyms (string []) - optional
  • If a function is user-defined, this field is ignored.
  • One or more aliases can be described.
• description (string)
  • one line explanation for a function
• detail (string) - optional
  • more explanations which can be two or more lines
• example
  • what are parameters and what is a result.

Function signatures can be derived from function name, parameters, and return types.

Issue Links

• blocks: TAJO-512 (Umbrella) 0.8 Release Preparation