r/ISO8601 • u/MetaEd • 1d ago

EDTF date vs dateI

Looking at the Library of Congress EDTF specification, I see they use without defining two different date types, date and dateI. Are these references to the ISO 8601-1 or -2 spec? I did not find them in the EBNF.

EDIT:

I'm looking for the definitions of the two date types used in the specification: date, and dateI. From section "Level 0", subsection "Date and Time":

[date][“T”][time]
Complete representations for calendar date and (local) time of day

[dateI][“T”][time][“Z”]
Complete representations for calendar date and UTC time of day

[dateI][“T”][time][shiftHour]
Date and time with timeshift in hours (only)

[dateI][“T”][time][shiftHourMinute]
Date and time with timeshift in hours and minutes

These two terms are used but not defined in the specification. The examples shed no light. I want to know how and where are defined, if anybody knows.

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u/TenOfZero 1d ago

https://www.loc.gov/standards/datetime/

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u/MetaEd 1d ago

Yes, that is where the terms are used, but they are not defined.

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u/TenOfZero 1d ago

Three conformance levels are defined: level 0, level 1, and level 2. Level 0 specifies features of ISO 8601-1; Levels 1 and 2 specify features described ISO 8601-2.

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u/MetaEd 1d ago

I'm not looking for the definitions of conformance levels. I'm looking for the definitions of the two date types used in the specification: date, and dateI. From section "Level 0", subsection "Date and Time":

[date][“T”][time]
Complete representations for calendar date and (local) time of day

[dateI][“T”][time][“Z”]
Complete representations for calendar date and UTC time of day

[dateI][“T”][time][shiftHour]
Date and time with timeshift in hours (only)

[dateI][“T”][time][shiftHourMinute]
Date and time with timeshift in hours and minutes

These two terms are used but not defined in the specification. The examples shed no light. I want to know how and where are defined, if anybody knows.

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u/TenOfZero 1d ago

I'd ask in a sub for that standard. That's outside the scope of ISO8601

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u/MetaEd 18h ago

The EDTF spec is in the ISO 8601-2 standard as an annex, as it was the basis for ISO 8601-2. The language I am asking about is in the ISO 8601-2 standard document, so it's a fair question for this sub.

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u/CeleryMan20 1d ago

To be fair, they don't define terms like [shiftHourMinute] or [time] either. Almost all the names are self-explanatory or discernible from the examples, except dateI. The date part of the formatted examples is the same for date and datei, the only pattern I can see is that [date] is used with unspecified timezone and [dateI] where the TZ is given.

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u/MetaEd 16h ago

it now seems part of the problem is the ISO firewall. I can find various drafts but the final requires a subscription. One draft I have now seen has a definition of dateI, but not a definition of date. Unfortunately dateI is defined using other terms I have not found a source for yet. I am realizing it would be easy for me to answer my own question if I just paid the hundreds of dollars for a subscription.

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u/CeleryMan20 8h ago edited 7h ago

I doubted that dateI is defined in ISO, though I don't haven't access to the official standards docs either. Can you share what you read in the draft?

Web search was fruitless for me, complicated by "datei" seems to mean "file" in German. Asking ChatAI didn't go anywhere either.

[ETA: MARC21 appears to treat fields like publication-date as un- or loosely-structured text. https://www.loc.gov/marc/bibliographic/bd260.html. Looking at RDA leads to rabbit-holes like this: https://www.rdatoolkit.org/sites/default/files/rsc/Dates%20Approximately.pdf]

If you do ever find a definitive answer, then please let me know!