Struct DefinedTerms 

pub struct DefinedTerms(/* private fields */);

Tracks which terms of one context definition are already defined and which are still being defined, so that cyclic definitions can be detected.

Defining a term can require defining others first — its prefix, or the term its @id names — so define recurses. A term that is reached again while its own definition is still in progress is a cycle.

Implementations

impl DefinedTerms

pub fn new() -> Self

Creates an empty tracker, with no term defined or in progress.

pub fn begin<E>(&mut self, key: &KeyOrKeyword) -> Result<bool, Error<E>>

Marks key as being defined, and reports whether the caller should go on to build its definition.

Returns Ok(true) for a term seen for the first time, Ok(false) for one already fully defined (the caller should do nothing), and Err(Error::CyclicIriMapping) for one whose definition is still in progress further up the recursion.

Errors

Returns an error when the term is already being defined further up the stack, which is a cyclic IRI mapping.

pub fn end(&mut self, key: &KeyOrKeyword)

Marks key as fully defined, so that reaching it again is no longer a cycle.

Does nothing if the term was never passed to Self::begin.

Trait Implementations

impl Default for DefinedTerms

fn default() -> Self

Returns the “default value” for a type.