Trait VariableResolver 

pub trait VariableResolver {
    // Required methods
    fn resolve_name(&mut self, name: &str) -> Result<Option<Value>>;
    fn resolve_qualified(
        &mut self,
        qualifier: &str,
        column: &str,
    ) -> Result<Option<Value>>;
    fn resolve_param(&mut self, index: usize) -> Result<Option<Value>>;
}

Resolves routine variables while a compiled expression / statement is being specialized for one execution.

Required Methods

fn resolve_name(&mut self, name: &str) -> Result<Option<Value>>

Current value of an unqualified name. Ok(None) leaves the column reference for the engine to resolve.

fn resolve_qualified( &mut self, qualifier: &str, column: &str, ) -> Result<Option<Value>>

Current value of qualifier.column (record field access).

fn resolve_param(&mut self, index: usize) -> Result<Option<Value>>

Value of a positional $n reference (function arguments).

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors