Negative time ranges

[jotaen]

In analogy to tracking a negative duration (-1h) it could be useful to allow tracking “negative” time ranges, i.e. a specific period of time to be deduced from the total.

Syntax ideas:

2020-01-01
    8:00-17:00 Work
    -12:00-13:00 Lunch break
    -(12:00-13:00) Lunch break
    -[12:00-13:00] Lunch break

Currently favouring the [] syntax, as it’s more distinct from the should-total.

Source: #3

[acikek]

Why does it need to be wrapped in () or []?

[jotaen]

My reasoning was for visual clarity. It’s not necessary from a technical point of view, but I feel that it might be too easy to overlook otherwise. I added the “naked” version as well in the example above, I’m also open to any other suggestion.

[vladdeSV]

I am in favor of wrapping in (), with the same reasoning as @jotaen:

for visual clarity.

[vladdeSV]

How would whitespace be handled inside and before the parentheses?

Are the following okay?

2021-04-20
  -(0:00-1:00) foo
  -    ( 0:00   -      1:00  ) foo

[ulken]

I would love to see this happen. Personally, no extra syntax is needed as the syntax highlighting would make it obvious, but maybe people don't use that?

If still deemed necessary, () resembles negating a mathematical expression, so that's makes sense. On the other hand, [] indicates the endpoints are to be included in the interval (see Notation for intervals), which is the case here?

[jotaen]

Cross-posting from #244 (reply in thread), regarding the current state of affairs here:

Negative time ranges are not off the table. Realistically speaking, however, I have to say that adding negative time ranges is a pretty comprehensive undertaking – deciding on the syntax and semantics is the easiest part, but extending the spec, writing and refactoring the code, and documenting it will be substantial effort. It might eventually happen, but it would certainly take a while.

[jotaen]

Opened #252 to get things going. (Still no ETA though.)