Struct QueryResult

pub struct QueryResult {
    pub expressions: Vec<Expression>,
    pub bindings: Value,
}

Result of evaluating a Rego query.

A query containing single expression.

// Create engine and evaluate "1 + 2".
let results = Engine::new().eval_query("1 + 2".to_string(), false)?;

// Fetch the first (sole) result.
let result = &results.result[0];

assert_eq!(result.expressions[0].value, Value::from(3u64));
assert_eq!(result.expressions[0].text.as_ref(), "1 + 2");

A query containing multiple expressions.

// Create engine and evaluate "1 + 2; 3.5 * 4".
let results = Engine::new().eval_query("1 + 2; 3.55 * 4".to_string(), false)?;

// Fetch the first (sole) result.
let result = &results.result[0];

// First expression.
assert_eq!(result.expressions[0].value, Value::from(3u64));
assert_eq!(result.expressions[0].text.as_ref(), "1 + 2");

// Second expression.
assert_eq!(result.expressions[1].value, Value::from(14.2));
assert_eq!(result.expressions[1].text.as_ref(), "3.55 * 4");

Expressions that create bindings (i.e. associate names to values) evaluate to either true or false. The value of bindings are available in the bindings field.

// Create engine and evaluate "x = 1; y = x > 0".
let results = Engine::new().eval_query("x = 1; y = x > 0".to_string(), false)?;

// Fetch the first (sole) result.
let result = &results.result[0];

// First expression is true.
assert_eq!(result.expressions[0].value, Value::from(true));
assert_eq!(result.expressions[0].text.as_ref(), "x = 1");

// Second expression is true.
assert_eq!(result.expressions[1].value, Value::from(true));
assert_eq!(result.expressions[1].text.as_ref(), "y = x > 0");

// bindings contains the value for each named expession.
assert_eq!(result.bindings[&Value::from("x")], Value::from(1u64));
assert_eq!(result.bindings[&Value::from("y")], Value::from(true));

If any expression evaluates to false, then no results are produced.

// Create engine and evaluate "true; true; false".
let results = Engine::new().eval_query("true; true; false".to_string(), false)?;

assert!(results.result.is_empty());

Fields

expressions: Vec<Expression>

Expressions in the query.

Each statement in the query is treated as a separte expression.

bindings: Value

Bindings created in the query.

Trait Implementations

impl Clone for QueryResult

fn clone(&self) -> QueryResult

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for QueryResult

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

Formats the value using the given formatter.

impl Default for QueryResult

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for QueryResult

fn eq(&self, other: &QueryResult) -> 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 Serialize for QueryResult

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for QueryResult

impl StructuralPartialEq for QueryResult