Types as a bucket of values

A type

For example:

- INTEGER

- PersonnelRecord

. . .

= An abstract value

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Notes:

Again, the slide is not specific to tagging, but helps to set the scene! The term “abstract value” is often used in ASN.1. It means a value without any concern about how it might be represented in a computer or on a communications line.

A useful mental picture is to consider all types as buckets containing a set of values.

This model underlies an addition to ASN.1 in the late 1990s that is informally described as “the semantic model” for ASN.1.

In the slide, we show a bucket that might be the INTEGER type, containing values 0, 1, -1, 2, -2, 3, etc, or which might be a bucket containing the set of rather more complicated values of the type PersonelRecord.