Struct expr::explain::ViewExplanation

pub struct ViewExplanation<'a> {
    expr_humanizer: &'a dyn ExprHumanizer,
    nodes: Vec<ExplanationNode<'a>>,
    expr_chains: HashMap<*const MirRelationExpr, usize>,
    local_id_chains: HashMap<LocalId, usize>,
    chain_local_ids: HashMap<usize, LocalId>,
    chain: usize,
}

An ViewExplanation facilitates pretty-printing of a MirRelationExpr.

By default, the fmt::Display implementation renders the expression as described in the module docs. Additional information may be attached to the explanation via the other public methods on the type.

Fields

expr_humanizer: &'a dyn ExprHumanizer

nodes: Vec<ExplanationNode<'a>>

One ExplanationNode for each MirRelationExpr in the plan, in left-to-right post-order.

expr_chains: HashMap<*const MirRelationExpr, usize>

Records the chain ID that was assigned to each expression.

local_id_chains: HashMap<LocalId, usize>

Records the chain ID that was assigned to each let.

chain_local_ids: HashMap<usize, LocalId>

Records the local ID that corresponds to a chain ID, if any.

chain: usize

The ID of the current chain. Incremented while constructing the Explanation.

Implementations

impl<'a> ViewExplanation<'a>

pub fn new(
    expr: &'a MirRelationExpr,
    expr_humanizer: &'a dyn ExprHumanizer
) -> ViewExplanation<'a>

pub fn explain_types(&mut self)

Attach type information into the explanation.

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

fn fmt_join_implementation(
    &self,
    f: &mut Formatter<'_>,
    join_inputs: &[MirRelationExpr],
    implementation: &JoinImplementation
) -> Result

fn expr_chain(&self, expr: &MirRelationExpr) -> usize

Retrieves the chain ID for the specified expression.

The ExplanationNode for expr must have already been inserted into the explanation.

Trait Implementations

impl<'a> Debug for ViewExplanation<'a>

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

Formats the value using the given formatter.

impl<'a> Display for ViewExplanation<'a>

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

Formats the value using the given formatter.