Struct Query 

pub struct Query { /* private fields */ }

An immutable Datalog query value.

Start from one of the find* constructors, chain :in and :where builders, and render with Query::to_edn. The query shape (relation/collection/tuple/scalar) is fixed by which constructor is used and determines the shape of the crate::QueryResult.

Implementations

impl Query

pub fn find<E: Into<FindElem>>(elems: impl IntoIterator<Item = E>) -> Self

A relation query :find ?a ?b yielding a set of tuples.

pub fn find_rel(elems: Vec<FindElem>) -> Self

A relation query from an explicit list of find elements. Use this when mixing element kinds, e.g. a variable and a pull expression.

pub fn find_coll(elem: impl Into<FindElem>) -> Self

A collection query :find [?x ...] yielding a flat list of values.

pub fn find_tuple<E: Into<FindElem>>(elems: impl IntoIterator<Item = E>) -> Self

A tuple query :find [?a ?b] yielding a single tuple.

pub fn find_scalar(elem: impl Into<FindElem>) -> Self

A scalar query :find ?x . yielding a single value.

pub fn with(self, vars: impl IntoIterator<Item = Var>) -> Self

Adds :with grouping variables (kept out of :find but preserved for aggregate cardinality).

pub fn in_db(self, name: impl Into<String>) -> Self

Declares an additional database source input such as $hist, bound positionally after the default $.

pub fn in_rules(self) -> Self

Declares a rule-set input %.

pub fn in_scalar(self, var: Var) -> Self

Declares a scalar input ?x.

pub fn in_tuple(self, vars: Vec<Var>) -> Self

Declares a tuple input [?x ?y].

pub fn in_coll(self, var: Var) -> Self

Declares a collection input [?x ...].

pub fn in_rel(self, vars: Vec<Var>) -> Self

Declares a relation input [[?x ?y]].

pub fn where_(self, clause: impl Into<Clause>) -> Self

Adds the first :where clause (or another one; identical to Query::and).

pub fn and(self, clause: impl Into<Clause>) -> Self

Adds another :where clause.

pub fn has_inputs(&self) -> bool

Whether this query declares any non-database :in inputs (rules, scalars, tuples, collections, or relations), which the caller must supply as arguments.

pub fn to_edn(&self) -> Edn

Renders the query to its boundary Edn map form.

Trait Implementations

impl Clone for Query

fn clone(&self) -> Query

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Query

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

Formats the value using the given formatter.

impl Eq for Query

impl PartialEq for Query

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Query