Enum Binding 

pub enum Binding {
    BindScalar(Variable),
    BindColl(Variable),
    BindRel(Vec<VariableOrPlaceholder>),
    BindTuple(Vec<VariableOrPlaceholder>),
}

Variants

BindScalar(Variable)

BindColl(Variable)

BindRel(Vec<VariableOrPlaceholder>)

BindTuple(Vec<VariableOrPlaceholder>)

Implementations

impl Binding

pub fn variables(&self) -> Vec<Option<Variable>>

Return each variable or None, in order.

pub fn is_empty(&self) -> bool

Return true if no variables are bound, i.e., all binding entries are placeholders.

pub fn is_valid(&self) -> bool

Return true if no variable is bound twice, i.e., each binding entry is either a placeholder or unique.

use edn::query::{Binding,Variable,VariableOrPlaceholder};
use std::rc::Rc;

let v = "?foo".to_var();
let vv = VariableOrPlaceholder::Variable(v);
let p = VariableOrPlaceholder::Placeholder;

let e = Binding::BindTuple(vec![p.clone()]);
let b = Binding::BindTuple(vec![p.clone(), vv.clone()]);
let d = Binding::BindTuple(vec![vv.clone(), p, vv]);
assert!(b.is_valid());          // One var, one placeholder: OK.
assert!(!e.is_valid());         // Empty: not OK.
assert!(!d.is_valid());         // Duplicate var: not OK.

Trait Implementations

impl Clone for Binding

fn clone(&self) -> Binding

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl ContainsVariables for Binding

fn accumulate_mentioned_variables(&self, acc: &mut BTreeSet<Variable>)

fn collect_mentioned_variables(&self) -> BTreeSet<Variable>

impl Debug for Binding

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

Formats the value using the given formatter.

impl Display for Binding

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

Formats the value using the given formatter.

impl Eq for Binding

impl PartialEq for Binding

fn eq(&self, other: &Binding) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Binding