.. index:: single: tzif_protocol
.. _tzif_protocol/0:

.. rst-class:: right

**protocol**

``tzif_protocol``
=================

Protocol for loading TZif data sets, persisting loaded terms, and answering zone-aware UTC-based offset, DST, and abbreviation queries.

| **Availability:** 
|    ``logtalk_load(tzif(loader))``

| **Author:** Paulo Moura
| **Version:** 1:0:0
| **Date:** 2026-04-07

| **Compilation flags:**
|    ``static``


| **Dependencies:**
|   (none)


| **Remarks:**
|    (none)

| **Inherited public predicates:**
|    (none)

.. contents::
   :local:
   :backlinks: top

Public predicates
-----------------

.. index:: load/1
.. _tzif_protocol/0::load/1:

``load/1``
^^^^^^^^^^

Loads a TZif source given as ``file(Path, ZoneId)``, ``files(Root, Paths)``, ``directory(Root)``, ``stream(Stream, ZoneId)``, ``bytes(Bytes, ZoneId)``, or ``snapshot(File)`` and caches the resulting per-zone ``tzif(...)`` terms, replacing cached entries with matching zone identifiers. For ``directory(Root)`` sources, regular files whose relative paths are not recognized zone identifiers are ignored, allowing system zoneinfo trees that contain metadata files such as ``leapseconds``. Zone identifiers are validated against bundled IANA TZDB 2026a canonical names plus backward-compatible aliases.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``load(Source)``
| **Mode and number of proofs:**
|    ``load(+compound)`` - ``zero_or_one``


------------

.. index:: load/2
.. _tzif_protocol/0::load/2:

``load/2``
^^^^^^^^^^

Loads a TZif source given as ``file(Path, ZoneId)``, ``files(Root, Paths)``, ``directory(Root)``, ``stream(Stream, ZoneId)``, ``bytes(Bytes, ZoneId)``, or ``snapshot(File)`` into a list of per-zone ``tzif(...)`` compound terms without caching them. For ``directory(Root)`` sources, regular files whose relative paths are not recognized zone identifiers are ignored, allowing system zoneinfo trees that contain metadata files such as ``leapseconds``. Zone identifiers are validated against bundled IANA TZDB 2026a canonical names plus backward-compatible aliases.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``load(Source,TZifs)``
| **Mode and number of proofs:**
|    ``load(+compound,-list(compound))`` - ``zero_or_one``


------------

.. index:: cache/1
.. _tzif_protocol/0::cache/1:

``cache/1``
^^^^^^^^^^^

Caches one or more loaded per-zone ``tzif(...)`` compound terms, replacing cached entries with matching zone identifiers.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``cache(TZifs)``
| **Mode and number of proofs:**
|    ``cache(+list(compound))`` - ``one``


------------

.. index:: save/2
.. _tzif_protocol/0::save/2:

``save/2``
^^^^^^^^^^

Saves a list of per-zone ``tzif(...)`` terms to a plain Prolog snapshot file, writing one serialized term per line.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``save(TZifs,File)``
| **Mode and number of proofs:**
|    ``save(+list(compound),+atom)`` - ``one``


------------

.. index:: save/1
.. _tzif_protocol/0::save/1:

``save/1``
^^^^^^^^^^

Saves all cached ``tzif(...)`` terms to a plain Prolog snapshot file.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``save(File)``
| **Mode and number of proofs:**
|    ``save(+atom)`` - ``one_or_error``


------------

.. index:: clear_cache/0
.. _tzif_protocol/0::clear_cache/0:

``clear_cache/0``
^^^^^^^^^^^^^^^^^

Clears all cached TZif terms.

| **Compilation flags:**
|    ``static``

| **Mode and number of proofs:**
|    ``clear_cache`` - ``one``


------------

.. index:: cache_source/1
.. _tzif_protocol/0::cache_source/1:

``cache_source/1``
^^^^^^^^^^^^^^^^^^

Enumerates the source terms recorded in the cached TZif terms.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``cache_source(Source)``
| **Mode and number of proofs:**
|    ``cache_source(-compound)`` - ``zero_or_more``


------------

.. index:: cached_tzif/1
.. _tzif_protocol/0::cached_tzif/1:

``cached_tzif/1``
^^^^^^^^^^^^^^^^^

Enumerates the cached per-zone ``tzif(...)`` terms.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``cached_tzif(TZif)``
| **Mode and number of proofs:**
|    ``cached_tzif(-compound)`` - ``zero_or_more``


------------

.. index:: zone/3
.. _tzif_protocol/0::zone/3:

``zone/3``
^^^^^^^^^^

Returns the loaded zone identifier and its nested parsed zone-data term from a per-zone ``tzif(...)`` term.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``zone(TZif,Zone,ZoneData)``
| **Mode and number of proofs:**
|    ``zone(+compound,?atom,-compound)`` - ``zero_or_one``


------------

.. index:: zones/2
.. _tzif_protocol/0::zones/2:

``zones/2``
^^^^^^^^^^^

Returns the list of zone identifiers loaded in a list of per-zone ``tzif(...)`` terms.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``zones(TZifs,Zones)``
| **Mode and number of proofs:**
|    ``zones(+list(compound),-list(atom))`` - ``one``


------------

.. index:: zones/1
.. _tzif_protocol/0::zones/1:

``zones/1``
^^^^^^^^^^^

Returns the list of zone identifiers loaded in the cached ``tzif(...)`` terms.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``zones(Zones)``
| **Mode and number of proofs:**
|    ``zones(-list(atom))`` - ``one_or_error``


------------

.. index:: time_type/4
.. _tzif_protocol/0::time_type/4:

``time_type/4``
^^^^^^^^^^^^^^^

Returns the applicable local time type for a loaded zone and a UTC instant given either as Unix seconds or as a ``date_time/6`` term.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``time_type(TZif,Zone,UTC,TimeType)``
| **Mode and number of proofs:**
|    ``time_type(+compound,+atom,+types([integer,compound]),-compound)`` - ``zero_or_one``


------------

.. index:: time_type/3
.. _tzif_protocol/0::time_type/3:

``time_type/3``
^^^^^^^^^^^^^^^

Returns the applicable local time type for a zone in the cached TZif terms.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``time_type(Zone,UTC,TimeType)``
| **Mode and number of proofs:**
|    ``time_type(+atom,+types([integer,compound]),-compound)`` - ``one_or_error``


------------

.. index:: time_type/2
.. _tzif_protocol/0::time_type/2:

``time_type/2``
^^^^^^^^^^^^^^^

Cached single-zone convenience variant of ``time_type/3`` using the cached TZif terms; requires exactly one cached zone.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``time_type(UTC,TimeType)``
| **Mode and number of proofs:**
|    ``time_type(+types([integer,compound]),-compound)`` - ``one_or_error``


------------

.. index:: offset/4
.. _tzif_protocol/0::offset/4:

``offset/4``
^^^^^^^^^^^^

Returns the UTC offset in seconds for a loaded zone and a UTC instant.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``offset(TZif,Zone,UTC,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``offset(+compound,+atom,+types([integer,compound]),-integer)`` - ``zero_or_one``


------------

.. index:: offset/3
.. _tzif_protocol/0::offset/3:

``offset/3``
^^^^^^^^^^^^

Returns the UTC offset in seconds for a zone in the cached TZif terms.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``offset(Zone,UTC,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``offset(+atom,+types([integer,compound]),-integer)`` - ``one_or_error``


------------

.. index:: offset/2
.. _tzif_protocol/0::offset/2:

``offset/2``
^^^^^^^^^^^^

Cached single-zone convenience variant of ``offset/3`` using the cached TZif terms; requires exactly one cached zone.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``offset(UTC,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``offset(+types([integer,compound]),-integer)`` - ``one_or_error``


------------

.. index:: daylight_saving_time/4
.. _tzif_protocol/0::daylight_saving_time/4:

``daylight_saving_time/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns ``true`` or ``false`` according to whether daylight saving time is active for a loaded zone and a UTC instant.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``daylight_saving_time(TZif,Zone,UTC,IsDST)``
| **Mode and number of proofs:**
|    ``daylight_saving_time(+compound,+atom,+types([integer,compound]),-atom)`` - ``zero_or_one``


------------

.. index:: daylight_saving_time/3
.. _tzif_protocol/0::daylight_saving_time/3:

``daylight_saving_time/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns daylight-saving information for a zone in the cached TZif terms.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``daylight_saving_time(Zone,UTC,IsDST)``
| **Mode and number of proofs:**
|    ``daylight_saving_time(+atom,+types([integer,compound]),-atom)`` - ``one_or_error``


------------

.. index:: daylight_saving_time/2
.. _tzif_protocol/0::daylight_saving_time/2:

``daylight_saving_time/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of ``daylight_saving_time/3`` using the cached TZif terms; requires exactly one cached zone.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``daylight_saving_time(UTC,IsDST)``
| **Mode and number of proofs:**
|    ``daylight_saving_time(+types([integer,compound]),-atom)`` - ``one_or_error``


------------

.. index:: abbreviation/4
.. _tzif_protocol/0::abbreviation/4:

``abbreviation/4``
^^^^^^^^^^^^^^^^^^

Returns the time-zone abbreviation for a loaded zone and a UTC instant.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``abbreviation(TZif,Zone,UTC,Abbreviation)``
| **Mode and number of proofs:**
|    ``abbreviation(+compound,+atom,+types([integer,compound]),-atom)`` - ``zero_or_one``


------------

.. index:: abbreviation/3
.. _tzif_protocol/0::abbreviation/3:

``abbreviation/3``
^^^^^^^^^^^^^^^^^^

Returns the time-zone abbreviation for a zone in the cached TZif terms.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``abbreviation(Zone,UTC,Abbreviation)``
| **Mode and number of proofs:**
|    ``abbreviation(+atom,+types([integer,compound]),-atom)`` - ``one_or_error``


------------

.. index:: abbreviation/2
.. _tzif_protocol/0::abbreviation/2:

``abbreviation/2``
^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of ``abbreviation/3`` using the cached TZif terms; requires exactly one cached zone.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``abbreviation(UTC,Abbreviation)``
| **Mode and number of proofs:**
|    ``abbreviation(+types([integer,compound]),-atom)`` - ``one_or_error``


------------

.. index:: local_time_type/4
.. _tzif_protocol/0::local_time_type/4:

``local_time_type/4``
^^^^^^^^^^^^^^^^^^^^^

Returns the applicable local time type for a loaded zone and a local civil time given as a ``date_time/6`` term. This strict variant fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type(TZif,Zone,LocalDateTime,TimeType)``
| **Mode and number of proofs:**
|    ``local_time_type(+compound,+atom,+compound,-compound)`` - ``zero_or_one``


------------

.. index:: local_time_type/3
.. _tzif_protocol/0::local_time_type/3:

``local_time_type/3``
^^^^^^^^^^^^^^^^^^^^^

Returns the applicable local time type for a zone in the cached TZif terms. This strict variant fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type(Zone,LocalDateTime,TimeType)``
| **Mode and number of proofs:**
|    ``local_time_type(+atom,+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_time_type/2
.. _tzif_protocol/0::local_time_type/2:

``local_time_type/2``
^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of strict local civil-time lookup; requires exactly one cached zone and fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type(LocalDateTime,TimeType)``
| **Mode and number of proofs:**
|    ``local_time_type(+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_time_type_with_resolution/5
.. _tzif_protocol/0::local_time_type_with_resolution/5:

``local_time_type_with_resolution/5``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the applicable local time type for a loaded zone and a local civil time using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type_with_resolution(TZif,Zone,LocalDateTime,ResolutionMode,TimeType)``
| **Mode and number of proofs:**
|    ``local_time_type_with_resolution(+compound,+atom,+compound,+atom,-compound)`` - ``zero_or_more``


------------

.. index:: local_time_type_with_resolution/4
.. _tzif_protocol/0::local_time_type_with_resolution/4:

``local_time_type_with_resolution/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the applicable local time type for a zone in the cached TZif terms using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type_with_resolution(Zone,LocalDateTime,ResolutionMode,TimeType)``
| **Mode and number of proofs:**
|    ``local_time_type_with_resolution(+atom,+compound,+atom,-compound)`` - ``zero_or_more``


------------

.. index:: local_time_type_with_resolution/3
.. _tzif_protocol/0::local_time_type_with_resolution/3:

``local_time_type_with_resolution/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of local civil-time lookup using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order). Requires exactly one cached zone.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type_with_resolution(LocalDateTime,ResolutionMode,TimeType)``
| **Mode and number of proofs:**
|    ``local_time_type_with_resolution(+compound,+atom,-compound)`` - ``zero_or_more``


------------

.. index:: local_offset/4
.. _tzif_protocol/0::local_offset/4:

``local_offset/4``
^^^^^^^^^^^^^^^^^^

Returns the UTC offset in seconds for a loaded zone and a local civil time. This strict variant fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset(TZif,Zone,LocalDateTime,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``local_offset(+compound,+atom,+compound,-integer)`` - ``zero_or_one``


------------

.. index:: local_offset/3
.. _tzif_protocol/0::local_offset/3:

``local_offset/3``
^^^^^^^^^^^^^^^^^^

Returns the UTC offset in seconds for a zone in the cached TZif terms. This strict variant fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset(Zone,LocalDateTime,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``local_offset(+atom,+compound,-integer)`` - ``one_or_error``


------------

.. index:: local_offset/2
.. _tzif_protocol/0::local_offset/2:

``local_offset/2``
^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of strict local civil-time offset lookup.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset(LocalDateTime,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``local_offset(+compound,-integer)`` - ``one_or_error``


------------

.. index:: local_offset_with_resolution/5
.. _tzif_protocol/0::local_offset_with_resolution/5:

``local_offset_with_resolution/5``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the UTC offset in seconds for a loaded zone and a local civil time using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset_with_resolution(TZif,Zone,LocalDateTime,ResolutionMode,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``local_offset_with_resolution(+compound,+atom,+compound,+atom,-integer)`` - ``zero_or_more``


------------

.. index:: local_offset_with_resolution/4
.. _tzif_protocol/0::local_offset_with_resolution/4:

``local_offset_with_resolution/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the UTC offset in seconds for a zone in the cached TZif terms using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset_with_resolution(Zone,LocalDateTime,ResolutionMode,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``local_offset_with_resolution(+atom,+compound,+atom,-integer)`` - ``zero_or_more``


------------

.. index:: local_offset_with_resolution/3
.. _tzif_protocol/0::local_offset_with_resolution/3:

``local_offset_with_resolution/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of local civil-time offset lookup using the explicit resolution mode; requires exactly one cached zone.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset_with_resolution(LocalDateTime,ResolutionMode,OffsetSeconds)``
| **Mode and number of proofs:**
|    ``local_offset_with_resolution(+compound,+atom,-integer)`` - ``zero_or_more``


------------

.. index:: local_daylight_saving_time/4
.. _tzif_protocol/0::local_daylight_saving_time/4:

``local_daylight_saving_time/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns daylight-saving information for a loaded zone and a local civil time. This strict variant fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time(TZif,Zone,LocalDateTime,IsDST)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time(+compound,+atom,+compound,-atom)`` - ``zero_or_one``


------------

.. index:: local_daylight_saving_time/3
.. _tzif_protocol/0::local_daylight_saving_time/3:

``local_daylight_saving_time/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns daylight-saving information for a zone in the cached TZif terms. This strict variant fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time(Zone,LocalDateTime,IsDST)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time(+atom,+compound,-atom)`` - ``one_or_error``


------------

.. index:: local_daylight_saving_time/2
.. _tzif_protocol/0::local_daylight_saving_time/2:

``local_daylight_saving_time/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of strict local daylight-saving lookup.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time(LocalDateTime,IsDST)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time(+compound,-atom)`` - ``one_or_error``


------------

.. index:: local_daylight_saving_time_with_resolution/5
.. _tzif_protocol/0::local_daylight_saving_time_with_resolution/5:

``local_daylight_saving_time_with_resolution/5``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns daylight-saving information for a loaded zone and a local civil time using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time_with_resolution(TZif,Zone,LocalDateTime,ResolutionMode,IsDST)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time_with_resolution(+compound,+atom,+compound,+atom,-atom)`` - ``zero_or_more``


------------

.. index:: local_daylight_saving_time_with_resolution/4
.. _tzif_protocol/0::local_daylight_saving_time_with_resolution/4:

``local_daylight_saving_time_with_resolution/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns daylight-saving information for a zone in the cached TZif terms using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time_with_resolution(Zone,LocalDateTime,ResolutionMode,IsDST)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time_with_resolution(+atom,+compound,+atom,-atom)`` - ``zero_or_more``


------------

.. index:: local_daylight_saving_time_with_resolution/3
.. _tzif_protocol/0::local_daylight_saving_time_with_resolution/3:

``local_daylight_saving_time_with_resolution/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of local civil-time daylight-saving lookup using the explicit resolution mode; requires exactly one cached zone.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time_with_resolution(LocalDateTime,ResolutionMode,IsDST)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time_with_resolution(+compound,+atom,-atom)`` - ``zero_or_more``


------------

.. index:: local_abbreviation/4
.. _tzif_protocol/0::local_abbreviation/4:

``local_abbreviation/4``
^^^^^^^^^^^^^^^^^^^^^^^^

Returns the time-zone abbreviation for a loaded zone and a local civil time. This strict variant fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation(TZif,Zone,LocalDateTime,Abbreviation)``
| **Mode and number of proofs:**
|    ``local_abbreviation(+compound,+atom,+compound,-atom)`` - ``zero_or_one``


------------

.. index:: local_abbreviation/3
.. _tzif_protocol/0::local_abbreviation/3:

``local_abbreviation/3``
^^^^^^^^^^^^^^^^^^^^^^^^

Returns the time-zone abbreviation for a zone in the cached TZif terms. This strict variant fails unless the local civil time has a unique interpretation.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation(Zone,LocalDateTime,Abbreviation)``
| **Mode and number of proofs:**
|    ``local_abbreviation(+atom,+compound,-atom)`` - ``one_or_error``


------------

.. index:: local_abbreviation/2
.. _tzif_protocol/0::local_abbreviation/2:

``local_abbreviation/2``
^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of strict local abbreviation lookup.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation(LocalDateTime,Abbreviation)``
| **Mode and number of proofs:**
|    ``local_abbreviation(+compound,-atom)`` - ``one_or_error``


------------

.. index:: local_abbreviation_with_resolution/5
.. _tzif_protocol/0::local_abbreviation_with_resolution/5:

``local_abbreviation_with_resolution/5``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the time-zone abbreviation for a loaded zone and a local civil time using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation_with_resolution(TZif,Zone,LocalDateTime,ResolutionMode,Abbreviation)``
| **Mode and number of proofs:**
|    ``local_abbreviation_with_resolution(+compound,+atom,+compound,+atom,-atom)`` - ``zero_or_more``


------------

.. index:: local_abbreviation_with_resolution/4
.. _tzif_protocol/0::local_abbreviation_with_resolution/4:

``local_abbreviation_with_resolution/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the time-zone abbreviation for a zone in the cached TZif terms using the explicit resolution mode: ``strict`` (fail unless exactly one interpretation exists), ``first`` (prefer the earliest valid interpretation), ``second`` (prefer the latest valid interpretation), and ``all`` (enumerate all valid interpretations in chronological order).

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation_with_resolution(Zone,LocalDateTime,ResolutionMode,Abbreviation)``
| **Mode and number of proofs:**
|    ``local_abbreviation_with_resolution(+atom,+compound,+atom,-atom)`` - ``zero_or_more``


------------

.. index:: local_abbreviation_with_resolution/3
.. _tzif_protocol/0::local_abbreviation_with_resolution/3:

``local_abbreviation_with_resolution/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of local civil-time abbreviation lookup using the explicit resolution mode; requires exactly one cached zone.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation_with_resolution(LocalDateTime,ResolutionMode,Abbreviation)``
| **Mode and number of proofs:**
|    ``local_abbreviation_with_resolution(+compound,+atom,-atom)`` - ``zero_or_more``


------------

.. index:: local_time_type_reified/4
.. _tzif_protocol/0::local_time_type_reified/4:

``local_time_type_reified/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns a reified local civil-time lookup result for a loaded zone as one of ``unique(TimeType)``, ``ambiguous(TimeTypes)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type_reified(TZif,Zone,LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_time_type_reified(+compound,+atom,+compound,-compound)`` - ``one``


------------

.. index:: local_time_type_reified/3
.. _tzif_protocol/0::local_time_type_reified/3:

``local_time_type_reified/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns a reified local civil-time lookup result for a zone in the cached TZif terms as one of ``unique(TimeType)``, ``ambiguous(TimeTypes)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type_reified(Zone,LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_time_type_reified(+atom,+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_time_type_reified/2
.. _tzif_protocol/0::local_time_type_reified/2:

``local_time_type_reified/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of reified local civil-time lookup; returns ``unique(TimeType)``, ``ambiguous(TimeTypes)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_time_type_reified(LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_time_type_reified(+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_offset_reified/4
.. _tzif_protocol/0::local_offset_reified/4:

``local_offset_reified/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns a reified local offset lookup result for a loaded zone as one of ``unique(OffsetSeconds)``, ``ambiguous(OffsetSecondsList)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset_reified(TZif,Zone,LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_offset_reified(+compound,+atom,+compound,-compound)`` - ``one``


------------

.. index:: local_offset_reified/3
.. _tzif_protocol/0::local_offset_reified/3:

``local_offset_reified/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns a reified local offset lookup result for a zone in the cached TZif terms as one of ``unique(OffsetSeconds)``, ``ambiguous(OffsetSecondsList)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset_reified(Zone,LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_offset_reified(+atom,+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_offset_reified/2
.. _tzif_protocol/0::local_offset_reified/2:

``local_offset_reified/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of reified local offset lookup; returns ``unique(OffsetSeconds)``, ``ambiguous(OffsetSecondsList)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_offset_reified(LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_offset_reified(+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_daylight_saving_time_reified/4
.. _tzif_protocol/0::local_daylight_saving_time_reified/4:

``local_daylight_saving_time_reified/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns a reified local daylight-saving lookup result for a loaded zone as one of ``unique(IsDST)``, ``ambiguous(IsDSTList)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time_reified(TZif,Zone,LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time_reified(+compound,+atom,+compound,-compound)`` - ``one``


------------

.. index:: local_daylight_saving_time_reified/3
.. _tzif_protocol/0::local_daylight_saving_time_reified/3:

``local_daylight_saving_time_reified/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns a reified local daylight-saving lookup result for a zone in the cached TZif terms as one of ``unique(IsDST)``, ``ambiguous(IsDSTList)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time_reified(Zone,LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time_reified(+atom,+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_daylight_saving_time_reified/2
.. _tzif_protocol/0::local_daylight_saving_time_reified/2:

``local_daylight_saving_time_reified/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of reified local daylight-saving lookup; returns ``unique(IsDST)``, ``ambiguous(IsDSTList)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_daylight_saving_time_reified(LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_daylight_saving_time_reified(+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_abbreviation_reified/4
.. _tzif_protocol/0::local_abbreviation_reified/4:

``local_abbreviation_reified/4``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns a reified local abbreviation lookup result for a loaded zone as one of ``unique(Abbreviation)``, ``ambiguous(Abbreviations)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation_reified(TZif,Zone,LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_abbreviation_reified(+compound,+atom,+compound,-compound)`` - ``one``


------------

.. index:: local_abbreviation_reified/3
.. _tzif_protocol/0::local_abbreviation_reified/3:

``local_abbreviation_reified/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns a reified local abbreviation lookup result for a zone in the cached TZif terms as one of ``unique(Abbreviation)``, ``ambiguous(Abbreviations)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation_reified(Zone,LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_abbreviation_reified(+atom,+compound,-compound)`` - ``one_or_error``


------------

.. index:: local_abbreviation_reified/2
.. _tzif_protocol/0::local_abbreviation_reified/2:

``local_abbreviation_reified/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cached single-zone convenience variant of reified local abbreviation lookup; returns ``unique(Abbreviation)``, ``ambiguous(Abbreviations)``, or ``nonexistent``.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``local_abbreviation_reified(LocalDateTime,Result)``
| **Mode and number of proofs:**
|    ``local_abbreviation_reified(+compound,-compound)`` - ``one_or_error``


------------

Protected predicates
--------------------

(none)

Private predicates
------------------

(none)

Operators
---------

(none)

