Module pushdown 

Predicate Pushdown Framework

This module provides a clean, extensible architecture for predicate pushdown. Each pushdown rule is self-contained and implements the PushdownRule trait.

Adding a New Pushdown Rule

1. Create a new struct implementing PushdownRule
2. Register it in PushdownRegistry::new()
3. Done!

Example

pub struct MyCustomRule;

impl PushdownRule for MyCustomRule {
    fn name(&self) -> &'static str { "my_custom_rule" }

    fn try_convert(
        &self,
        expr: &ast::Expression,
        ctx: &PushdownContext<'_>,
    ) -> PushdownResult {
        // Check if this rule applies and convert
    }
}

Structs

PushdownContext

Context for pushdown operations

PushdownPlan

PushdownRegistry

Registry of all pushdown rules

Enums

PushdownResult

Result of a pushdown attempt

Traits

PushdownRule

Trait for pushdown rules

Functions

registry

Get the global pushdown registry

try_pushdown

Convenience function to try pushdown using the global registry

try_pushdown_plan