Struct BindingSet 

pub struct BindingSet { /* private fields */ }

A set of SPARQL solution mappings (bindings).

Each element is a mapping from variable names to RDF terms. Implements the SPARQL algebra operations: MINUS, EXISTS, UNION, PROJECT, JOIN, DISTINCT.

Implementations

impl BindingSet

pub fn new() -> Self

Create an empty binding set.

pub fn from_vec(bindings: Vec<HashMap<String, RdfTerm>>) -> Self

Create a binding set from a vector of solution mappings.

pub fn add(&mut self, binding: HashMap<String, RdfTerm>)

Add a single solution mapping.

pub fn len(&self) -> usize

Number of solution mappings in this set.

pub fn is_empty(&self) -> bool

Returns true if this binding set contains no solutions.

pub fn minus(&self, other: &BindingSet) -> BindingSet

SPARQL MINUS operation.

Returns a binding set containing only those rows from self that are NOT compatible with any row in other that shares at least one variable.

W3C SPARQL 1.1 spec §18.5: A row μ₁ from Ω₁ is removed if there exists μ₂ in Ω₂ such that:

• dom(μ₁) ∩ dom(μ₂) ≠ ∅ (they share at least one variable)
• μ₁ and μ₂ are compatible on shared variables

If no row in other shares any variable with a row in self, the row is KEPT.

pub fn exists_filter(&self, pattern: &BindingSet) -> BindingSet

EXISTS filter: keep rows from self that are compatible with at least one row in pattern.

Two rows are compatible if all their shared variables agree in value. Rows with no shared variables are considered compatible.

pub fn union(&self, other: &BindingSet) -> BindingSet

UNION: combine all rows from both binding sets.

pub fn project(&self, vars: &[&str]) -> BindingSet

PROJECT: keep only the named variables in each solution mapping.

Variables not in vars are dropped. Solutions that become identical after projection are NOT automatically deduplicated (call distinct separately).

pub fn join(&self, other: &BindingSet) -> BindingSet

Natural JOIN: for each pair of rows from self and other that are compatible (agree on all shared variables), produce the merged row.

pub fn distinct(&self) -> BindingSet

DISTINCT: remove duplicate solution mappings.

pub fn iter(&self) -> impl Iterator<Item = &HashMap<String, RdfTerm>>

Iterate over all solution mappings in this set.

pub fn is_compatible( a: &HashMap<String, RdfTerm>, b: &HashMap<String, RdfTerm>, ) -> bool

Two solution mappings are compatible if, for every variable they both bind, they agree on the value.

Rows with no shared variables are always compatible.

Trait Implementations

impl Clone for BindingSet

fn clone(&self) -> BindingSet

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BindingSet

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

Formats the value using the given formatter.

impl Default for BindingSet

fn default() -> BindingSet

Returns the “default value” for a type.

impl IntoIterator for BindingSet

type Item = HashMap<String, RdfTerm>

The type of the elements being iterated over.

type IntoIter = IntoIter<HashMap<String, RdfTerm>>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.