Struct EvalCtx 

pub struct EvalCtx<'a> {
    pub resolver: Option<&'a Resolver<'a>>,
    pub outer: Option<&'a Bound<'a>>,
}

What an expression may reach beyond its own row.

Both fields exist for subqueries. The resolver is what lets a subquery RUN from inside an expression, and outer is the enclosing query’s row, so WHERE attrelid = c.oid inside ARRAY(SELECT ... FROM pg_attribute a ...) can see c — a correlated subquery, which is what every one of psql’s subqueries is.

Scoping follows SQL: a name resolves in the innermost query that binds it, and only then in the enclosing one. That matters for the bare column in \dp’s WHERE oid = ANY (polroles): oid is the inner pg_roles row’s, polroles is the outer pg_policy row’s, and neither is qualified.

Fields

resolver: Option<&'a Resolver<'a>>

outer: Option<&'a Bound<'a>>

Trait Implementations

impl<'a> Clone for EvalCtx<'a>

fn clone(&self) -> EvalCtx<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for EvalCtx<'a>

impl<'a> Default for EvalCtx<'a>

fn default() -> EvalCtx<'a>

Returns the “default value” for a type.