Vague term "meaningful" used often

[petervwyatt]

A large number of places (49 to be precise – see attached XLSX file) in ISO 32000-2 describe keys as being “meaningful” under certain conditions. This is a vague and unclear term, as it is unclear what “meaningful” really means and how/when you codify or might validate that, or if it has exactly the same meaning in every case.

Meaningful.xlsx

[petervwyatt]

I think "X, meaningful only if Y" means:

• key X must be optional - makes no sense if X is always required
• if Y is false, then X is completely ignored and, for example, if it had the wrong value or a wrong type then it would not be an error
• if Y is true, then X might be required or optional (depends on each usage??) but it must have the correct type and value
• Y cannot refer back to key X directly or indirectly with “meaningful” statements (circular confusion!)
• in each case, is Y fully sufficient or insufficient?

ISO 32000 also uses "required when ..." style statements so how is "meaningful when ..." different? Should any occurrences be "required when ..."?

Anything else??

[lrosenthol]

From looking over the spreadsheet, I agree that most of them are of the form "X is optional and/or ignored unless key Y meets some criteria" (where some criteria is usually either present and/or true, though may also be of a certain type).

There are a few where it is used in a more "editorial" fashion (eg. 14.5 NOTE) but a better word would suffice.

[MPBailey]

Leaping into a solution rather than further problem analysis, would it work to replace "X is only meaningful if Y" with "X shall be ignored unless Y"?

That would retain the existing additional semantics around being optional if Y etc.

That doesn't help with ArtBox and "the page's meaningful content" of course ..., or the various statements along the lines of "operators shall be meaningful only inside a content stream". I'm not convinced that most of the latter are ... meaningful? useful? anyway!

[petervwyatt]

I interpret "... shall be ignored if ..." as a clearer statement since this also implies that validators shall(!) not report the key or key value under the stated condition (so even if it was invalid it is technically not a reportable error because of the presence of the other key). Of course "... shall not be present ..." is an even stronger statement.

I also agree a number of uses of the word "meaningful" are also more casual/editorial but I'm not so concerned with them.