Struct ExprEngine 

pub struct ExprEngine { /* private fields */ }

Compiles and evaluates the JSONLogic a definition is written in.

Cheap to clone: a clone shares the datalogic engine, the operator table and the secrets.

Implementations

impl ExprEngine

pub fn interpolated(&self, raw: &Value) -> Result<Interpolated, Vec<Issue>>

Compiles a document of var holes in otherwise literal data.

Advisories and Defects (a payload hole, an operator left as data) are dropped on Ok; a config field compiled through ConfigField is the way to get them.

Errors

Every issue, when any is Rejected.

impl ExprEngine

pub fn builder() -> ExprEngineBuilder

Starts a builder.

pub fn operators(&self) -> &[Operator]

Every operator this engine evaluates: the datalogic built-ins its selected families enable, then the host’s operators in registration order, then secret.

pub fn secrets(&self) -> &Secrets

The secrets the secret operator reads.

pub fn escape(&self) -> char

The template-key escape: $.

pub fn compile<T: FromValue>(&self, raw: &Value) -> Result<Expr<T>>

Compiles raw. An expression that reads nothing is evaluated once, here, and kept as its T.

Errors

ErrorKind::Compile when datalogic refuses the expression; ErrorKind::Eval when evaluating a constant at fold time fails; ErrorKind::Config when a folded constant is not a T.

pub fn eval<'e, 'r, T: FromValue>( &self, expr: &'e Expr<T>, root: impl EvalRoot<'r>, ) -> Result<Evaluated<T::Out<'e>>>

Evaluates expr against root, an object holding the three context roots, as an OwnedDataValue or a serde_json::Value (EvalRoot). A folded constant is lent from expr and takes no arena.

Errors

ErrorKind::Budget when the operation ceiling is exceeded; ErrorKind::Eval for any other failure, including a result that is not a T.

Trait Implementations

impl Clone for ExprEngine

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ExprEngine

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

Formats the value using the given formatter.

impl Default for ExprEngine

fn default() -> Self

Returns the “default value” for a type.