Hashtag (#) from @base prefix is lost during parsing?

[Lenostatos]

Hello,

when I execute the example code from the README with the following turtle data, the resulting quads are not what I am expecting.

import ParserN3 from '@rdfjs/parser-n3'
import { Readable } from 'readable-stream'

const parserN3 = new ParserN3()

const input = Readable.from(`
@base <http://www.w3.org/2000/01/rdf-schema#> .
@prefix rdf: <../../1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <> .
@prefix owl: <../../2002/07/owl#> .
@prefix dc: <http://purl.org/dc/elements/1.1/> .

<>
    dc:title "The RDF Schema vocabulary (RDFS)" ;
    a owl:Ontology ;
    rdfs:seeAlso <rdf-schema-more> .

rdfs:Class
    a rdfs:Class ;
    rdfs:comment "The class of classes." ;
    rdfs:isDefinedBy <> ;
    rdfs:label "Class" ;
    rdfs:subClassOf rdfs:Resource .
`)

const output = parserN3.import(input)

output.on('data', quad => {
  console.log(`quad: ${quad.subject.value} - ${quad.predicate.value} - ${quad.object.value}`)
})

output.on('prefix', (prefix, ns) => {
  console.log(`prefix: ${prefix} ${ns.value}`)
})

Please note the missing hash symbol (#) at the end of the rdfs prefix in line 2, which is propagated to every place where the prefix was used in the turtle data:

I hope this is not just me being stupid, but at least on this website, the turtle is parsed as expected.

Thank you for your time!

[bergos]

According to the Turtle specification, the base IRI should be resolved as described in RFC 3986, which says:

If the base URI is obtained from a URI reference, then that reference must be converted to absolute form and stripped of any fragment component prior to its use as a base URI.

To my understanding, the behavior is correct, and the parsed output of the mentioned web page is wrong.

This library is just a wrapper for N3.js, where the parsing of the base and prefixes happens. Let's forward the question:

@RubenVerborgh can you confirm my assumption?

[RubenVerborgh]

Correct indeed; we have a whole bunch of tests for IRI resolution cases (https://github.com/rdfjs/N3.js/blob/v1.17.3/test/N3Parser-test.js#L2591), because we discovered back in the day that many parsers had different interpretations (https://lists.w3.org/Archives/Public/public-rdf-comments/2015Aug/0000.html).

[Lenostatos]

I see, thank you very much @bergos and @RubenVerborgh for your time! Then I will forward this to my turtle source 😅