Struct rsonpath_lib::query::automaton::Automaton

pub struct Automaton<'q> { /* private fields */ }

A minimal, deterministic automaton representing a JSONPath query.

Implementations

impl<'q> Automaton<'q>

pub fn new(query: &'q JsonPathQuery) -> Result<Self, CompilerError>

Convert a JsonPathQuery into a minimal deterministic automaton.

Errors

CompilerError::NotSupportedError raised if the query contains elements not yet supported by the compiler.

pub fn is_empty_query(&self) -> bool

Returns whether this automaton represents an empty JSONPath query (‘$’).

Examples

let query = JsonPathQuery::parse("$").unwrap();
let automaton = Automaton::new(&query).unwrap();

assert!(automaton.is_empty_query());

let query = JsonPathQuery::parse("$.a").unwrap();
let automaton = Automaton::new(&query).unwrap();

assert!(!automaton.is_empty_query());

pub fn rejecting_state(&self) -> State

Returns the rejecting state of the automaton.

The state is defined as the unique state from which there exists no accepting run. If the query automaton reaches this state, the current subtree is guaranteed to have no matches.

pub fn initial_state(&self) -> State

Returns the initial state of the automaton.

Query execution should start from this state.

pub fn accepting_state(&self) -> State

Returns the accepting state of the automaton.

Query execution should treat transitioning into this state as a match.

pub fn is_accepting(&self, state: State) -> bool

Returns whether the given state is accepting.

Example

let query = JsonPathQuery::parse("$.a").unwrap();
let automaton = Automaton::new(&query).unwrap();

assert!(automaton.is_accepting(automaton.accepting_state()));

pub fn is_rejecting(&self, state: State) -> bool

Returns whether the given state is rejecting, i.e. there exist no accepting runs from it.

Example

let query = JsonPathQuery::parse("$.a").unwrap();
let automaton = Automaton::new(&query).unwrap();

assert!(automaton.is_rejecting(automaton.rejecting_state()));

Trait Implementations

impl<'q> Debug for Automaton<'q>

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

Formats the value using the given formatter.

impl<'q> Display for Automaton<'q>

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

Formats the value using the given formatter.

impl<'q> Index<State> for Automaton<'q>

type Output = TransitionTable<'q>

The returned type after indexing.

fn index(&self, index: State) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<'q> PartialEq<Automaton<'q>> for Automaton<'q>

fn eq(&self, other: &Automaton<'q>) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

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

impl<'q> Eq for Automaton<'q>

impl<'q> StructuralEq for Automaton<'q>

impl<'q> StructuralPartialEq for Automaton<'q>