H.450 - "Loose" specification of SyntaxList in X.681?

[Frank Derks]

Dear experts,

since H.450 heavily relies on Information Object Classes and since
the H.450 supplementary services use the user-friendly syntax, I
have a question relating to the syntax of the specification of this
syntax.

X.681 defines SyntaxList as:

SyntaxList ::= "{" TokenOrGroupSpec empty + "}"

Other definitions from X.681, that "complete" this specification,
are:

  TokenOrGroupSpec ::= RequiredToken | OptionalGroup
  OptionalGroup ::= "[" TokenOrGroupSpec empty + "]"
  RequiredToken ::=     Literal |       PrimitiveFieldName
  Literal ::= word | ","

For "required" fields from the class, the "syntax list" would
usually contain phrases consisting of some uppercase description
consisting of one or more words (separated by spaces),followed by
one of the fields from the class, etc.

Obviously, this is covered by the above BNF of X.681, but (as an
example) "RETURN ,, &ResultType RESULT" would be just as valid as
"RETURN RESULT &ResultType" with this definition.

Do I interpret the BNF wrongly, or is this indeed the case?

Regards,

Frank

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