Adding a :number offset option

[mihnita]

Fix for issue #701

[mihnita]

TODO: add tests.

But I wanted to unblock the splitting of the registry in separate files.
Plus, the wording is the the part that might be controversial.
The tests, not so much.

[eemeli]

If the option is available on :number, it should also be on :integer.

OTOH, if it only supports whole number values, it might make sense to only allow on :integer; I'm not aware of any use case for it having been presented for non-integer values.

I also submitted #927 as the text around resolved value should be clarified.

[eemeli]

If the offset is applied to the numerical value of the resolved value and the offset option is also retained in the resolved options, doesn't that mean that it may get double-applied?

[mihnita]

This is the trouble with using :integer (or :number) for both formatting and selection.

So selection you need both the offset, and the original value.
Because you test the exact values against the original value, and the keywords against the value - offset.

But for formatting the value - offset is enough, and you can drop the offset from the resolved options.

Which means that if one does

.input {$count :integer offset=2}
.match $count
...

then the resolved value for $count should have the offset.

If we separated the :input / :number from :plural this would have an easy answer: :plural keeps the resolved value and resolved options "as is", and :integer resolves the value to the value - offset and remove the offset from the resolved values.

I am not pushing to revert that decision.
We voted and all.

But I am open to suggestions, because I am not sure what to do here.

[mihnita]

Idea: leave the resolved value as is, and leave the offset in the resolved options.
Then the selection can see both.
And the "formatted value" (which we don't have a concept of, although it would be useful) can do the diff.

Trouble is that without the concept of "formatted value" we can't fully describe how the formatting works.

We have a section named "Numeric Value Selection and Formatting", but we don't seem to describe the formatting part at all.

[eemeli]

Is there a reason why a negative offset is not allowed?

[mihnita]

I can't imagine a use case for it.
ICU works. But also works with fractional values. And negative fractional values. And with fractional arguments (see my other comment)

[macchiati]

The purpose is to list the first n members of a list explicitly, then switch on the remaining number. Negative doesn't have any usage.

[ray007]

ICU compatibility sounds like a good argument to me.

[aphillips]

Partial review

[aphillips]

Why wouldn't ordinal work the same way?

[mihnita]

Why wouldn't ordinal work the same way?

I think we discussed it in the last meeting and nobody was able to come up with a use case for ordinals.

But ICU supports it.
So I am open to add it.

[aphillips]

list = { Audrey, Bill, Carlos, David, Edna, Freda}

.local $first = {$list :get item=1}
.local $second = {$list :get item=2}
.local $user = {$list :get item=last}
.local $length = {$list :length}
.local $position = {$length :integer select=ordinal offset=2} 
.match $position
one {{After {$first} and {$second}, {$user} is {$position}st in line}}
two {{After {$first} and {$second}, {$user} is {$position}nd in line}}
... etc...

... but it's a pretty contrived use case...

[mihnita]

If the option is available on :number, it should also be on :integer.

OTOH, if it only supports whole number values, it might make sense to only allow on :integer; I'm not aware of any use case for it having been presented for non-integer values.

I also submitted #927 as the text around resolved value should be clarified.

Good catch, thank you.

I added the option to :integer

About removing it from :number, I am split.

I can't imagine a use case for non-int with offset.

BUT I have two reasons to keep it:

One is that ICU supports it.

You can pass a non-int argument and get "Alice, Bob, and 3.142 other guests".
You can also pass a non-int offset, and works.
And you can pass a negative offset (integer or not) and works.

I cannot imagine a use case for any of these...

The second reason I kept it was that I suspect that some devs would not be too careful about :number and :integer.
So functionally they would only pass integral values, but do the formatting and selection with :number.

---

But I am fine to say: no, we don't support any of this.
We only support 0 or positive integers for offset, and only only support offset on :integer.

Adding them later would be backward compatible.

[mihnita]

Summarizing the questions:

• should we support fractional and / or negative offsets?
• should we support offset on :number?
• should we support offset in ordinal mode?
• what to do with offset in the resolved options?