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Label Generation Rules for Portuguese

Overview

This document specifies a set of Label Generation Rules (LGR) for the Portuguese language using a language-specific repertoire for the second level domain or domains identified above. The format of this file follows [RFC 7940]. This LGR is adapted from the “Reference LGR for the Second Level for the Portuguese Language” [Ref-LGR-pt-Latn], for details, see Change History below.

Standalone LGR: This LGR is designed to be used in a zone that does not cater to IDNs other than those valid under this LGR. This LGR lacks features that would allow its use in the context of another LGR in the same zone, and it may contain other features incompatible with such use.

Repertoire

All references converge on 38 Latin code points.

There is no IDN table published in the IANA Repository of IDN Practices by a .pt ccTLD, but the registry provides IDN information [700].

Excluded code points

Letters documented in some references but not included:

• U+00E5 å LATIN SMALL LETTER A WITH RING ABOVE

• U+00E6 æ LATIN SMALL LETTER AE

• U+00E8 è LATIN SMALL LETTER E WITH GRAVE

• U+00EB ë LATIN SMALL LETTER E WITH DIAERESIS

• U+00EC ì LATIN SMALL LETTER I WITH GRAVE

• U+00EE î LATIN SMALL LETTER I WITH CIRCUMFLEX

• U+00EF ï LATIN SMALL LETTER I WITH DIAERESIS

• U+00F1 ñ LATIN SMALL LETTER N WITH TILDE

• U+00F2 ò LATIN SMALL LETTER O WITH GRAVE

• U+00F6 ö LATIN SMALL LETTER O WITH DIAERESIS

• U+00F8 ø LATIN SMALL LETTER O WITH STROKE

• U+00F9 ù LATIN SMALL LETTER U WITH GRAVE

• U+00FB û LATIN SMALL LETTER U WITH CIRCUMFLEX

• U+00FF ÿ LATIN SMALL LETTER Y WITH DIAERESIS

• U+0101 ā LATIN SMALL LETTER A WITH MACRON

• U+0103 ă LATIN SMALL LETTER A WITH BREVE

• U+0113 ē LATIN SMALL LETTER E WITH MACRON

• U+0115 ĕ LATIN SMALL LETTER E WITH BREVE

• U+012B ī LATIN SMALL LETTER I WITH MACRON

• U+012D ĭ LATIN SMALL LETTER I WITH BREVE

• U+014D ō LATIN SMALL LETTER O WITH MACRON

• U+014F ŏ LATIN SMALL LETTER O WITH BREVE

• U+0153 œ LATIN SMALL LIGATURE OE

• U+016B ū LATIN SMALL LETTER U WITH MACRON

• U+016D ŭ LATIN SMALL LETTER U WITH BREVE

While there is at least one lexical item in Portuguese (the word “ñ”) that uses U+00F1 ñ LATIN SMALL LETTER N WITH TILDE as given in [605] none of the other references include it, with the sole exception of the CLDR auxiliary set [402]. Lacking any evidence of common use, it is not included in the repertoire.

Extended code points

A number of letters not considered essential to writing the core vocabulary of the language are nevertheless in common use. Where they have not been added to the core repertoire, they are flagged as “extended-cp” in the table of code points. A context rule is provided that by default will prohibit labels with such extended code points. To support extended single code points or code point sequences, delete the context “extended-cp” from their repertoire definition.

For Portuguese, U+00FC ü LATIN SMALL LETTER U WITH DIAERESIS, is the only code point included in the extended set, It was part of the standard spelling but abolished in the Orthographic Agreement of 1990 [604].

Variants

No variants are applicable when using the LGR in a standalone fashion.

Character Classes

This LGR does not define named character classes.

Rules

Common Rules

By default, the LGR includes the rules and actions to implement the following restrictions mandated by the IDNA protocol. They are marked with ⍟.

• Hyphen Restrictions — restrictions on the allowable placement of hyphens (no leading/ending hyphen and no hyphen in positions 3 and 4). These restrictions are described in Section 4.2.3.1 of RFC 5891 [150]. They are implemented here as context rule on U+002D (-) HYPHEN-MINUS.
• Leading Combining Marks — restrictions on the allowable placement of combining marks (no leading combining mark). This rule is described in Section 4.2.3.2 of RFC 5891 [150].

Actions

This LGR includes the default actions for LGRs as well as the action needed to invalidate labels with misplaced combining marks. They are marked with ⍟. For a description see [RFC 7940].

Methodology and Contributors

The LGR in this document has been adapted from the corresponding Reference LGR for the Second Level. The Second Level Reference LGR for the Portuguese Language was developed by Michel Suignard and Asmus Freytag, including input by Michael Everson, Nicholas Ostler, and Wil Tan, and based on multiple open public consultations.

Changes from Version Dated 10 October 2016

Language tag has been updated.

Changes from Version Dated 18 May 2021

Unicode Version has been updated.

Changes from Version Dated 24 January 2024

Adopted from the Second Level Reference LGR for the Portuguese Language [Ref-LGR-pt-Latn] without normative changes.

References

General references for the language:

• Pilar Vásquez Cuesta & Maraia AAlbertina Mendes da Luz, Gramática da Língua Portuguesa,1980, Lisbon: edições 70
• Michaelis, Dicionario Prático, 1987, São Paulo: Cia. Melhoramentos de São Paulo (bilingual dictionary - Inglês-Português/Português-Inglês)

• Cook, Manuela. 1987. Portuguese. Sevenoaks: Hodder and Stoughton. ISBN 0-340-41231-3

• Barker, J. W. 1962. Teach yourself Portuguese. Edited and revised by L. Stringer. London: English Universities Press.

• Wikipedia: “Portuguese orthography”,
  https://en.wikipedia.org/wiki/Portuguese_alphabet

• Omniglot: “Portuguese (Português)”
  https://www.omniglot.com/writing/portuguese.htm

Other references cited in this document:

[Ref-LGR-pt-Latn]

ICANN, Second Level Reference Label Generation Rules for the Portuguese Language (pt-Latn), 24 January 2024 (XML)
https://www.icann.org/sites/default/files/packages/lgr/lgr-second-level-portuguese-language-24jan24-en.xml
non-normative HTML presentation:
https://www.icann.org/sites/default/files/packages/lgr/lgr-second-level-portuguese-language-24jan24-en.html

[RFC 7940]

Davies, K. and A. Freytag, “Representing Label Generation Rulesets Using XML”, RFC 7940, August 2016,
https://www.rfc-editor.org/info/rfc7940

[Unicode 11.0.0]

The Unicode Consortium. The Unicode Standard, Version 11.0.0, (Mountain View, CA: The Unicode Consortium, 2018. ISBN 978-1-936213-19-1)
https://www.unicode.org/versions/Unicode11.0.0/

In the listing of the repertoire by code point, references starting from [0] refer to the version of the Unicode Standard in which the corresponding code point was initially encoded. Other references (starting from [100]) document usage of code points. Entries in the table may have multiple source reference values. In the listing of whole label evaluation and context rules, reference [150] indicates the source for common rules. For more details, see the Table of References below.

Character Classes

Implict defined by script tag	2

The following table lists all named and implicit classes with their definition and a list of their members intersected with the current repertoire (for larger classes, this list is elided).

Name	Definition	Count	Members or Ranges	Ref	Comment
implicit	Tag=sc:Latn	39	{0061-007A 00E0-00E3 00E7 00E9-00EA 00ED 00F3-00F5 00FA 00FC}		Any character tagged as Latin
implicit	Tag=sc:Zyyy	11	{002D 0030-0039}		Any character tagged as Common

Legend

Members or Ranges

Lists the members of the class as code points (xxx) or as ranges of code points (xxx-yyy). Any class too numerous to list in full is elided with "...".

Tag=ttt

A named or implicit class defined by all code points that share the given tag value (ttt).

Implicit

An anonymous class implicitly defined based on tag value and for which there is no named equivalent.

Whole label evaluation and context rules

Number of rules	3
Used to trigger actions	1
Used as context rule (C)	2
Anchored context rules	1

The following table lists all named rules defined in the LGR and indicates whether they are used as trigger in an action or as context (when or not-when) for a code point or variant.

Name	Regular Expression	Used as Trigger	Anchor	Used as Context	Ref	Comment
leading-combining-mark	(start)[∅=[[∅=\p{gc=Mn}] ∪ [∅=\p{gc=Mc}]]]	✔			[150]	RFC 5891 restrictions on placement of combining marks ⍟
hyphen-minus-disallowed	(((start))← ⚓︎)|(⚓︎ →((end)))|(((start)..\u002D)← ⚓︎)		✔	C	[150]	RFC 5891 restrictions on placement of U+002D - ⍟
extended-cp	(start)(end)			C		context to gate off code points from the extended range, matches no label ⍟

Legend

Used as Trigger

This rule triggers one of the actions listed below.

Used as Context

This rule defines a required or prohibited context for a code point C or variant V.

Anchor

This rule has a placeholder for the code point for which it is evaluated.

Regular Expression

A regular expression equivalent to the rule, shown in a modified notation as noted:

⚓︎ - context anchor

Placeholder for the actual code point when a context is evaluated. The code point must occur at the position corresponding to the anchor. Rules containing an anchor cannot be used as triggers.

(...)← - look-behind

If present encloses required context preceding the anchor.

→(..) - look-ahead

If present encloses required context following the anchor.

( ) - group

An anonymous nested rule is used to group match operators.

(... | ...) - choice

When there is more than one alternative in a rule, the choices are separated by the alternation operator (...|...).

start or end

(start) matches the start of the label; (end) matches the end of the label.

. - any code point

. matches any code point.

[\p{ }] - property

Set of all characters matching a given value for a Unicode property [\p{prop=val}]. Note: uppercase “\P” defines the complement of a property set.

∪, ∩, ∖, ∆ - set operators

Sets may be combined by set operators (∪ = union, ∩ = intersection, ∖ = difference, ∆ = symmetric difference).

∅= - empty set

Indicates that the following set is empty because of the result of set operations, or because none of its elements is part of the repertoire defined here. A rule with a non-optional empty set never matches.

(^$) - empty label

The regex (^$) matches the empty label. Used as a context rule, it always fails to match, thus disallowing the affected code point in any label. By convention, it is used for context rules that disable code points that are not part of the repertoire, yet explicitly listed in the LGR as excluded or for optional future extension.

⍟ - default rule

Rules marked with ⍟ are included by default and may or may not be triggered by any possible label under this LGR.

Actions

The following table lists the actions that are used to assign dispositions to labels and variant labels based on the specified conditions. The order of actions defines their precedence: the first action triggered by a label is the one defining its disposition.

#	Condition	Rule / Variant Set		Disposition	Ref	Comment
1	if label matches	leading-combining-mark	→	invalid		by default, labels with leading combining marks are invalid
2	if any label (catch-all)		→	valid		catch all

Legend

{...} - variant type set

In the “Rule/Variant Set” column, the notation {...} means a set of variant types.