Can't parse Turtle (TTL) boolean values followed by a spacebar

[joepio]

Hi! just noticed a parsing issue.

go to https://www.easyrdf.org/converter

Try this:

@prefix dc: <http://purl.org/dc/terms/> .
@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dex: <https://dexpods.eu/ns/core#> .

<https://daan.staging.dexpods.eu/distributions/14> a <https://daan.staging.dexpods.eu/distributions/14>;
  dc:title true;
  dex:offer <https://daan.staging.dexpods.eu/offers/62160576efe0e3622296210e> .

Error! Turtle Parse Error: expected '.', found 'd' on line 7, column 4

However, ending with a . instead of ; works just fine:

@prefix dc: <http://purl.org/dc/terms/> .
@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dex: <https://dexpods.eu/ns/core#> .

<https://daan.staging.dexpods.eu/distributions/14> a <https://daan.staging.dexpods.eu/distributions/14>;
  dc:title true .

[zozlak]

It's not a dot versus semicolon but lack of space. Check:

@prefix dc: <http://purl.org/dc/terms/> .
@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dex: <https://dexpods.eu/ns/core#> .

<https://daan.staging.dexpods.eu/distributions/14> a <https://daan.staging.dexpods.eu/distributions/14>;
  dc:title true ;
  dex:offer <https://daan.staging.dexpods.eu/offers/62160576efe0e3622296210e> .

and

@prefix dc: <http://purl.org/dc/terms/> .
@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dex: <https://dexpods.eu/ns/core#> .

<https://daan.staging.dexpods.eu/distributions/14> a <https://daan.staging.dexpods.eu/distributions/14>;
  dc:title true.

Now someone should dig into the Turtle specification and check if it's a bug or maybe the syntax without space is not a valid Turtle. I'm afraid I won't do it.

[joepio]

Thanks for the quick reply! Pretty much all TTL validators that I tried succesfully parsed and validated the one with the spacebar for the .:

https://www.w3.org/2015/03/ShExValidata/

http://ttl.summerofcode.be/

http://rdfvalidator.mybluemix.net/

I think we can safely classify this as a parsing bug, at least practically - if most other implementations do parse this without errors.

[gkellogg]

In W3C EBNF grammars, such as Turtle, whitespace is typically not required, except in rare circumstances.

From the Turtle spec 6.1 White Space:

White space (production WS) is used to separate two terminals which would otherwise be (mis-)recognized as one terminal. Rule names below in capitals indicate where white space is significant; these form a possible choice of terminals for constructing a Turtle parser.

The rule names in capitals all denote terminal productions, although neither true nor false are terminal productions.