Are these grammars valid?

[KOLANICH]

When developing synalysis2kaitai I have encountered several anomalies in the grammars in this repo. Are these grammars valid? If they are, how should I treat them?

• Grammars/glb.grammar

  Line 20 in edcba05

  <binary name="chunk_type" id="15"/>

• Grammars/utf8.grammar

  Line 19 in edcba05

  <fixedvalues/>

• Grammars/bt.grammar

  Line 5 in edcba05

  <structure name="Marker" id="43" length="10" encoding="ISO_8859-1:1987" endian="big" signed="no" strokecolor="FEFFFF" fillcolor="000000"/>

• Grammars/bookmark.grammar

  Line 57 in edcba05

  <offset name="Bookmark Data" id="253" fillcolor="75D5FF" length="4" endian="little" references="id:252" relative-to="id:217" follownullreference="yes"/>

  - there is no id 217

[synalysis]

Hi, the grammars are valid however you brought up some details that could be improved in the grammar. In the first case the first binary element consumes the rest of the structure because it has no length. So the 2nd binary element is omitted (because it has no minimum length).

In the second case the element is empty and thus useless.

In the 3rd case: is what you consider problematic that the structures contain no elements?

Referencing a structure that doesn't exist is indeed a bug in the grammar.

[KOLANICH]

Thank you for the answers.

In the first case the first binary element consumes the rest of the structure because it has no length. So the 2nd binary element is omitted (because it has no minimum length).

Understood. BTW, should they be without length taking in account

Grammars/glb.grammar

Line 18 in edcba05

<structure name="JSONChunk" id="13" length="0" alignment="0" extends="id:8" encoding="ISO_8859-1:1987" endian="little" signed="no">

and

Grammars/glb.grammar

Line 30 in edcba05

<number name="version" id="20" fillcolor="FF40FD" type="integer" length="4"/>

In the second case the element is empty and thus useless.

How should I treat it? Should I just ignore it?

In the 3rd case: is what you consider problematic that the structures contain no elements?

Not very problematic (I can write some code to deal with it), but just pretty strange (I see no reasons to have such constructions, and I don't know how I should process them correctly).