Struct rio_turtle::NQuadsParser

pub struct NQuadsParser<R: BufRead> { /* private fields */ }

A N-Quads and N-Quads-star streaming parser.

It implements the QuadsParser trait.

Its memory consumption is linear in the size of the longest line of the file. It does not do any allocation during parsing except buffer resizing if a line significantly longer than the previous is encountered, or if a line uses deeply nested triples.

Count the number of people using the QuadsParser API:

use rio_turtle::{NQuadsParser, TurtleError};
use rio_api::parser::QuadsParser;
use rio_api::model::NamedNode;

let file = b"<http://example.com/foo> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://schema.org/Person> <http://example.com/> .
<http://example.com/foo> <http://schema.org/name> \"Foo\" <http://example.com/> .
<http://example.com/bar> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://schema.org/Person> .
<http://example.com/bar> <http://schema.org/name> \"Bar\" .";

let rdf_type = NamedNode { iri: "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" };
let schema_person = NamedNode { iri: "http://schema.org/Person" };
let mut count = 0;
NQuadsParser::new(file.as_ref()).parse_all(&mut |t| {
    if t.predicate == rdf_type && t.object == schema_person.into() {
        count += 1;
    }
    Ok(()) as Result<(), TurtleError>
})?;
assert_eq!(2, count);

Implementations

impl<R: BufRead> NQuadsParser<R>

pub fn new(reader: R) -> Self

Trait Implementations

impl<R: BufRead> QuadsParser for NQuadsParser<R>

type Error = TurtleError

fn parse_step<E: From<TurtleError>>( &mut self, on_quad: &mut impl FnMut(Quad<'_>) -> Result<(), E> ) -> Result<(), E>

Parses a small chunk of the file and calls on_quad each time a new quad is read. (A “small chunk” could be a line for an N-Quads parser.)

fn is_end(&self) -> bool

Returns true if the file has been completely consumed by the parser.

fn parse_all<E>( &mut self, on_quad: &mut impl FnMut(Quad<'_>) -> Result<(), E> ) -> Result<(), E>where E: From<Self::Error>,

Parses the complete file and calls on_quad each time a new quad is read.

fn into_iter<T, E, F>( self, convert_quad: F ) -> QuadsParserIterator<T, E, F, Self>where E: From<Self::Error>, F: FnMut(Quad<'_>) -> Result<T, E>,

Converts the parser into a Result<T, E> iterator.