Trait Row 

pub trait Row {
    // Required method
    fn get(&self, field: &FieldRef) -> Option<Value>;

    // Provided method
    fn try_get(&self, field: &FieldRef) -> Result<Option<Value>, EvalError> { ... }
}

Pluggable row-binding lookup. The evaluator stays agnostic of whether the caller has a slot vector indexed by planner-assigned position, a flat HashMap<String, Value>, or a graph binding — every consumer just provides a Row impl that resolves a FieldRef to a Value.

Required Methods

fn get(&self, field: &FieldRef) -> Option<Value>

Resolve a column / property reference. Returns None when the reference is unknown (the evaluator surfaces this as EvalError::UnknownColumn) or Some(Value::Null) when the column exists but the row’s value is null.

Provided Methods

fn try_get(&self, field: &FieldRef) -> Result<Option<Value>, EvalError>

Hosts which decode stored values can report operating failures instead of treating a denied read as an unknown or NULL column.

Dyn Compatibility

This trait is dyn compatible.

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

Implementors

impl<F> Row for F

where F: Fn(&FieldRef) -> Option<Value>,

Trivial Row impl over a flat (table, column) -> Value closure — useful for tests and for callers that only have a column-name map.