[Question]: If it's possible to design a new dsl for optimizer rules, so that we can add new optimizer by just add new rule files

[xiaoma20082008]

Describe your problem

As we know that almost all optimizers are based on rules, just like too functions: match and replace, means that if we match the expression, then we can replace the old expression to a new expression.

so can we

1. design a new dsl only for optimizer rule
2. write a tiny compiler and transform the dsl to rule(eg: c++ code)
3. then we don't need write new optimizer rules, just write the dsl code

here is an example:
if we has a Match And Replace function for Filter:

Match(Filter(AND, lhs = $1, rhs = true))  

Replace(Filter(AND, lhs = $1, rhs = true)) => $1

Then the sql expression

a = 'tom' AND b = true

can rewrite to the following directly:

a = 'tom'

[JinHai-CN]

Using a DSL to define RBO rules is a very cool approach. But, considering the road map of Infinity, we won't start the development of this feature, recently.