/// The number of columns in the relation.
///
/// This number is determined from the type, which is determined recursively
/// at non-trivial cost.
The number of columns in the relation.
This number is determined from the type, which is determined recursively
at non-trivial cost.
The number of columns in the relation . This number is determined from the type which is determined recursively at non - trivial cost .
pub fn arity(&self) -> usize {
        match self {
            MirRelationExpr::Constant { rows: _, typ } => typ.arity(),
            MirRelationExpr::Get { typ, .. } => typ.arity(),
            MirRelationExpr::Let { body, .. } => body.arity(),
            MirRelationExpr::Project { input: _, outputs } => outputs.len(),
            MirRelationExpr::Map { input, scalars } => input.arity() + scalars.len(),
            MirRelationExpr::FlatMap { input, func, .. } => {
                input.arity() + func.output_type().column_types.len()
            }
            MirRelationExpr::Filter { input, .. } => input.arity(),
            MirRelationExpr::Join { inputs, .. } => inputs.iter().map(|i| i.arity()).sum(),
            MirRelationExpr::Reduce {
                input: _,
                group_key,
                aggregates,
                ..
            } => group_key.len() + aggregates.len(),
            MirRelationExpr::TopK { input, .. } => input.arity(),
            MirRelationExpr::Negate { input } => input.arity(),
            MirRelationExpr::Threshold { input } => input.arity(),
            MirRelationExpr::Union { base, inputs: _ } => base.arity(),
            MirRelationExpr::ArrangeBy { input, .. } => input.arity(),
        }
    }
pub fn arity ( & self ) -> usize { match self { MirRelationExpr :: Constant { rows : _ , typ } => typ . arity ( ) , MirRelationExpr :: Get { typ , .. } => typ . arity ( ) , MirRelationExpr :: Let { body , .. } => body . arity ( ) , MirRelationExpr :: Project { input : _ , outputs } => outputs . len ( ) , MirRelationExpr :: Map { input , scalars } => input . arity ( ) + scalars . len ( ) , MirRelationExpr :: FlatMap { input , func , .. } => { input . arity ( ) + func . output_type ( ) . column_types . len ( ) } MirRelationExpr :: Filter { input , .. } => input . arity ( ) , MirRelationExpr :: Join { inputs , .. } => inputs . iter ( ) . map ( | i | i . arity ( ) ) . sum ( ) , MirRelationExpr :: Reduce { input : _ , group_key , aggregates , .. } => group_key . len ( ) + aggregates . len ( ) , MirRelationExpr :: TopK { input , .. } => input . arity ( ) , MirRelationExpr :: Negate { input } => input . arity ( ) , MirRelationExpr :: Threshold { input } => input . arity ( ) , MirRelationExpr :: Union { base , inputs : _ } => base . arity ( ) , MirRelationExpr :: ArrangeBy { input , .. } => input . arity ( ) , } }
The number of columns in the relation.
The number of columns in the relation .
&self