ISO request: must/cannot

[tkoeppe]

From the most recent submission to ISO:

Notes and examples cannot contain requirements (this includes negative requirements and permissions which imply a requirement i.e. “need not”, “cannot”), permissions “may”, or recommendations “should”. As per the ISO/IEC Directives Part 2, Clause 24: “Notes are used for giving additional information intended to assist the understanding or use of the text of the document. The document shall be usable without the notes.” The same applies to examples as per the ISO/IEC Directives Part 2, Clause 25 “Examples illustrate concepts presented in the document. The document shall be usable without the examples.”

Therefore, it is not permitted to include important information in a note, such as the above verbal forms.

Solutions for changing the wording in notes and examples include “are/is (not) expected to” or simply changing it to be present tense to make the text descriptive i.e. (“it must be aligned” can be “it is aligned” in a note or example). Otherwise, these notes and examples can be turned into a list format as normal text, removing “Note”. See in particular:

note in 5.6,
note 3 in 6.4.2 (negative requirement),
note 1 in 6.4.4 (negative requirement),
note in 6.7.5.5.3 (negative requirement),
notes 2 and 3 in 6.8.1 (negative requirement), etc.

There are also instances where “must” is used in notes and examples, where it appears to be an implicit requirement, and as mentioned at DIS, this is problematic because the not should not have any normative elements. I have made a list of these occurrences:

6.3, Note 3
7.2.3, NOTE 3
7.3.5, note,
7.5.5.3, Note 2
7.6.1.9, note 6
7.6.2.1, note 1,
7.6.2.8, note 11
7.6.2.9, note 1
9.2.9.2, note 3
11.4.6, note 1
11.4.7, note 8
11.5.1, note 3,
12.1, NOTE
13.1, note 4
13.7.2.4, note
13.10.3.2, note
Table 31, note
Table 33, note 2 (which should be corrected to “note”).
20.2.8.2, note 1
20.4.3.3, note 2, note 3
22.4.6, note
22.14.2.2, note 3
24.2.2.2, note 3
25.3.1, note 1
25.3.5.1, note
27.3.1, note 2

This list is non-exhaustive and does not cover the entire document. Please review all notes and examples in the document to ensure the ISO/IEC Directives Part 2, Clauses 24 and 25 are followed.