Re: Attribute markings - a question

It may or may not produce a correct grammar for that case, I will find out if I increase the stack size until I no longer get the recursive template error...

_________________
Tomos Hillman
eXpertML Ltd
+44 7793 242058
On 14 Oct 2021, 17:18 +0100, C. M. Sperberg-McQueen <cmsmcq@blackmesatech.com>, wrote:
> There’s an instance of this in the current ixml grammar for ixml (dchar, schar),
> so if JayParser produces a correct parse of that grammar, it passes this test.
>
> Michael
>
> > On 14,Oct2021, at 2:25 AM, Tom Hillman <tom@expertml.com> wrote:
> >
> > I think this is a great example of a test case, though: I'll have to test JayParser against this to be sure it won't fall over!
> >
> > _________________
> > Tomos Hillman
> > eXpertML Ltd
> > +44 7793 242058
> > On 13 Oct 2021, 16:11 +0100, C. M. Sperberg-McQueen <cmsmcq@blackmesatech.com>, wrote:
> > > Thank you; I had neglected, overlooked, or forgotten the words "regardless of marking of intermediate nonterminals”.
> > >
> > > Michael
> > >
> > > > On 13,Oct2021, at 3:16 AM, Steven Pemberton <steven.pemberton@cwi.nl> wrote:
> > > >
> > > > It may be just early in the morning and the coffee hasn't yet kicked in, but I don't see the problem.
> > > >
> > > > I checked in my implementation, making the grammar unambiguous in the process:
> > > >
> > > > S : @able, baker, @charlie.
> > > > able: string.
> > > > baker: string.
> > > > charlie: string.
> > > > string: ["abc"]*, ".".
> > > >
> > > > Input:
> > > > aaa.bbb.ccc.
> > > >
> > > > Result:
> > > > <S able='aaa.' charlie='ccc.'>
> > > > <baker>
> > > > <string>bbb.</string>
> > > > </baker>
> > > > </S>
> > > >
> > > > Which was what I was expecting.
> > > >
> > > > So assuming I'm not missing something obvious, I suspect that you need to reread the serialisation section of the spec:
> > > >
> > > > "
> > > > • A nonterminal attribute is serialised by outputting the name of the node as an attribute, and serialising all non-hidden terminal descendants of the node (regardless of marking of intermediate nonterminals), in order, as the value of the attribute.
> > > > "
> > > > which I think covers what you are asking for.
> > > >
> > > > The other side of this coin is:
> > > >
> > > > "
> > > > • A nonterminal element is serialised by outputting the name of the node as an XML tag, serialising all exposed attribute descendants, and then serialising all non-attribute children in order. An attribute is exposed if it is an attribute child, or an exposed attribute of a hidden element child (note this is recursive).
> > > > "
> > > >
> > > > Steven
> > > >
> > > > On Wednesday 13 October 2021 04:19:52 (+02:00), C. M. Sperberg-McQueen wrote:
> > > >
> > > > > Consider the grammar
> > > > >
> > > > > S : @able, baker, @charlie.
> > > > > able: string.
> > > > > baker: string.
> > > > > charlie: string.
> > > > > string: ~[]*.
> > > > >
> > > > > Is this grammar OK? (Yes, it’s hopelessly ambiguous, but that’s beside the point.)
> > > > >
> > > > > If we ignored the annotations, a raw parse tree for this grammar might look like this:
> > > > >
> > > > > <S>
> > > > > <able mark=“@"><string>aaa</string></able>
> > > > > <baker><string>aaa</string></able>
> > > > > <charlie mark=“@"><string>ccc</string></able>
> > > > > </S>
> > > > >
> > > > > Note that ‘string’ is implicitly marked serializable (^).
> > > > >
> > > > > When a nonterminal marked to be serialized as an element appears as a child of a nonterminal marked to be serialized as an attribute (as ’string’ here appears as a child of @able and @charlie), is the rule
> > > > >
> > > > > - Raise an error because the grammar cannot be serialized that way?
> > > > >
> > > > > - Omit the content of ’string’ from the value of @able and @charlie by analogy with what happens when we calculate the text node children of an element?
> > > > >
> > > > > - Ignore the marking on ’string’ on the grounds that we have already been told that @able is an attribute. Since elements cannot appear within attributes, the implicid ^ marking on ’string’ is ignored.
> > > > >
> > > > > The grammar for ixml offers two examples that seem relevant: in a raw parse tree, @name will dominate nodes labeled namestart and namefollower, which are explicitly marked non-serializable (-). @dstring and @sstring similarly dominate nodes labeled dchar and schar, which are implicitly marked ^. The attributes @from and @to directly dominate nodes labeled ‘character’ (marked -) and indirectly dominate nodes labeled ‘dchar’ and ’schar’ (implicitly ^).
> > > > >
> > > > > In the spirit of making things as simple as possible for the grammar authors, I suppose the right rule is “when constructing the value of an attribute, treat nonterminals marked ^ and - the same: recur through them” (the last possibility mentioned above).
> > > > >
> > > > > I apologize if this has been discussed before - I have the guilty sensation that it has been, and that I did not retain the answer.
> > > > >
> > > > > Michael
> > > > >
> > > > >
> > > > >
> > > > >
> > >
> > >
>