ITU-T Recommendations

This Technical Corrigendum solves identified defects in ITU-T Rec. X.692 | ISO/IEC 8825-3 which prevented its use in support of ITU-T Rec. X.891 | ISO/IEC 24824-1 "Fast Infoset". The changes introduced in this Corrigendum are summarized as follows:
– Removal of the restriction that prohibited recursive definition of encoding objects. This restriction was an undesirable (and probably unintended) limitation of the previous edition of the Recommendation | International Standard, because encoding objects are the natural means by which new "encoding rules" can be defined by using ECN, and the ASN.1 type definition notation is naturally recursive (as are all the standard encoding rules).
– Removal of ambiguity around the concept and the terminology of "exhibiting an identification handle". This is now clearly specified as a property of an encoding object (rather than as a property of the encodings produced by an encoding object).
– Clarification of the mechanism by which an encoding object (not based on a defined syntax) inherits an identification handle from another encoding object. The previous text was often imprecise or incomplete in this area.
– Removal of the restriction that prohibited multiple bit patterns (handle values) for the identification handle exhibited by an encoding object. This restriction prevented the use of a common and convenient technique whereby, given (for example) two alternatives, the first alternative always produces a well-known bit pattern and the second alternative never produces that same bit pattern.
– Removal of the restriction that prohibited an encoding object applied to the constructor in an "EncodeStructure" to specify structure replacement. This restriction was an undesirable (and probably unintended) limitation of the previous edition of the Recommendation | International Standard, because there is no other way of specifying structure replacement for an encoding structure.
– Resolution of an inconsistency between the declaration of an identification handle (EXHIBITS HANDLE &exhibited-handle) having an OPTIONAL handle name, and the use of an identification handle (DETERMINED BY handle HANDLE &handle-id) having a DEFAULT handle name (= "default-handle") with no relationship between these two things.
– Correction of typographical errors.