MySQL Bugs: #83439: templatize Item

Bug #83439	templatize Item_create
Submitted:	19 Oct 2016 7:18	Modified:	20 Oct 2016 15:00
Reporter:	Martin Hansson	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Optimizer	Severity:	S3 (Non-critical)
Version:		OS:	Any
Assigned to:		CPU Architecture:	Any

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Description:
This is a refactoring.

Every SQL function has corresponding Item_func and Item_create classes. The purpose of the latter is to instantiate the former when the function is resolved against its arguments. Currently a developer adding a new function has to create a new class and a singleton instance of it, about 12 lines of code in the best case. This refactoring introduces a macro that achieves the same in one line:

DECLARE_UNARY_FUNCTION_FACTORY(found_rows).

This patch deals with zero-argument functions. Patches will follow for one-argument, two-argument functions etc.

How to repeat:
Problems arise when adding or removing a function.

Posted by developer:
 
Fixed in 8.0.1.

Code cleanup. No changelog entry needed.