Struct OrderByClause 

pub struct OrderByClause {
    pub field: FieldRef,
    pub expr: Option<Expr>,
    pub ascending: bool,
    pub nulls_first: bool,
}

Order by clause.

Fase 2 migration: field is the legacy bare column reference and remains populated for back-compat with existing callers (SPARQL / Gremlin / Cypher translators, the planner cost model, etc.). The new expr slot carries an arbitrary Expr tree — when present, runtime comparators prefer it over field, so the parser can emit ORDER BY CAST(a AS INT), ORDER BY a + b * 2, etc. without breaking the rest of the codebase.

When expr is None, the clause behaves exactly like before. When expr is Some(Expr::Column(f)), runtime code may still use the legacy path — it’s equivalent. Constructors default expr to None so all existing call sites stay source-compatible.

Fields

field: FieldRef

Field to order by. Left populated even when expr is set so legacy consumers (planner cardinality estimate, cost model, mode translators) that still pattern-match on field keep working during the Fase 2 migration.

expr: Option<Expr>

Fase 2 expression-aware sort key. When Some, runtime order comparators evaluate this expression per row and sort on the resulting values — unlocks ORDER BY expr (Fase 1.6).

ascending: bool

Ascending or descending

nulls_first: bool

Nulls first or last

Implementations

impl OrderByClause

pub fn asc(field: FieldRef) -> Self

Create ascending order

pub fn desc(field: FieldRef) -> Self

Create descending order

pub fn with_expr(self, expr: Expr) -> Self

Attach an Expr sort key to an existing clause. Leaves field untouched so back-compat match sites keep their pattern.

Trait Implementations

impl Clone for OrderByClause

fn clone(&self) -> OrderByClause

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for OrderByClause

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.