Thai

Thai (language)

Second-Level Reference Label Generation Rules, 25 October 2024 Current

Download lgr-second-level-thai-language-25oct24-en.xml (34.3kb)

Summary

Version3 — Second Level Reference LGR
Date
Tag th (Thai)
Unicode11.0.0
Source filelgr-second-level-thai-language-25oct24-en.xml (34.3kb)

This ruleset is integrated into the Common (integrated set) ruleset of this release.

Description

INSTRUCTIONS

  • These instructions cover how to adopt an LGR based on this reference LGR for a given zone and how to prepare the file for deposit in the IANA Repository of IDN Practices.
  • As described the IANA procedure (https://www.iana.org/help/idn-repository-procedure) an LGR MUST contain the following elements in its header:
    • Script or Language Designator (see below for guidance)
    • Version Number (this must increase with each amendment to the LGR, even if the updates are limited to the header itself)
    • Effective Date (the date at which the policy becomes applicable in operational use)
    • Registry Contact Details (contact name, email address, and/or phone number)
  • The following information is optional:
    • Document creation date
    • Applicable Domain(s)
    • Changes made to the Reference LGR before adopting

Please add or modify the following items in the XML source code for this file before depositing the document in the IANA Repository. (https://www.iana.org/domains/idn-tables)

Meta Data

Note: version numbers start at 1. RFC 7940 recommends using simple integers. The version comment is optional, please replace or delete the default comment. Version comments may be used by some tools as part of the page header.

<version comment="[Please replace (or delete) the optional comment]">[Please fill in version number, starting at 1]</version>

<date>[Please fill in with publication date, in YYYY-MM-DD format]</date>

<validity-start>[Please fill in effective date, in YYYY-MM-DD format]</validity-start>

Note: the scope element may be repeated, so that the same document can serve for multiple domains.

<scope type="domain">[Please provide, in ".domain" format]</scope>

Registry Contact Information:

Please fill in the Registry Contact Details.

Change History

If you made technical modifications to the LGR, please summarize them in the Change History (and also note the details in the appropriate section of the description).

PLEASE DELETE THESE INSTRUCTIONS BEFORE DEPOSITING THE DOCUMENT

Read the rest of the description Show less

Registry Contact Details

  • Contact Name: [Please fill in Contact Name]
  • Email address: [Please fill in Email address]
  • Phone Number: [Please fill in optional Phone Number]

Label Generation Rules for the Thai Language

Overview

This document specifies a set of Label Generation Rules (LGR) for the Thai language for the second level domain or domains identified above. The ultimate starting point for the development of this LGR can be found in the related Root Zone LGR [RZ-LGR-Thai]. Note that while it is the Thai Script Root Zone LGR that forms the starting point, the LGR defined here covers the Thai Language. The format of this file follows [RFC 7940]. This LGR is adapted from the “Reference LGR for the Second Level for the Thai Language” [Ref-LGR-th-Thai], for details, see Change History below.

For details and additional background on the Thai script, see “Proposal for a Thai Script Root Zone LGR” [Proposal-Thai].

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

The repertoire contains 68 code points for letters used in the Thai language. In addition, three sequences have been defined. The sequence U+0E4D U+0E32 was defined to replace the disallowed U+0E33 SARA AM and to facilitate implementation of the WLE rule follows-consonant-tone as a context rule. The other two sequences were defined to restrict U+0E45 LAKKHANGYAO from appearing in any context other than these sequences. Accordingly, while U+0E45 is not listed by itself this brings the total of code points avaliable for letters to 69.

The repertoire is a subset of [Unicode 11.0.0]. For details, see Section 5, “Repertoire” in [Proposal-Thai]. (The proposal cited has been adopted for the Thai script portion of the Root Zone LGR.)

For the second level, the repertoire has been augmented with the ASCII digits, U+0030 to U+0039; Thai digits, U+0E50 to U+0E59; U+002D HYPHEN-MINUS; the abbreviation mark U+0E2F THAI CHARACTER PAIYANNOI; and the repetition mark U+0E46 THAI CHARACTER MAIYAMOK. Also, a special sequence using the abbreviation mark has been added for a total of 95 repertoire elements.

Repertoire Listing: Each code point or range is tagged with the script or scripts with which the code point is used and one or more other character categories. For each repertoire element, one or more references document sufficient justification for inclusion in the repertoire; see the “References” below. For code points that are part of the repertoire, comments identify the language using the code point, as well as alternate names of some code points.

Variants

This LGR defines no variants for letters, see Section 6, “Variants” in [Proposal-Thai].

Digit Variants: All Thai digits are treated as semantic variants of the corresponding common (ASCII) digits. By transitivity, they are also semantic variants of any native digits in scripts that also include the common digits. Such variant relations are deemed to exist implicitly by transitivity but are not listed explicitly in each reference LGR. Instead, if needed, they are applied by using the Common LGR in label processing.

Character Classes

The Thai Script is an abugida in which consonant–vowel sequences are written as a unit: each unit is based on a consonant letter, and vowel, tone mark or diacritic notation are secondary. It is written with the combining marks stacked above or below the base consonant, like diacritics in European languages. However, although the concepts are quite similar, the implementations are significantly different.

Consonants: There are 44 characters that are classified as consonants; code points from this subset have been given the tag “cons”. See Section 5.1, “Consonants” in [Proposal-Thai].

Vowels: The 18 vowel symbols pronounced after a consonant are non-sequential: they can be located before (lv) , after (fv), above (av) or below (bv) the consonant, or in a combination of these positions, code points from this subset have been given the tags “fv1”,"fv2", “fv3”, “av”, “bv”, or “lv”. There are three code point sequences defined that include vowels. (Code point sequences do not carry tag values; instead, for code point sequences the subset values are identified in comments). See Section 5.2, “Vowels” in [Proposal-Thai].

Tones: There are 5 phonemic tones: mid, low, falling, high, and rising. These 5 tones are represented by 4 tone marks plus the absence of a mark. Code points from this subset have been given the tag “tone”. See section 5.3, “Tone Marks” in [Proposal-Thai].

Diacritical Marks: There are 3 above diacritic symbols that have been included here and given the tag “ad”. They differ in their frequency and purpose of usage. See also the discussion in Section 5.,4 “Diacritics” in [Proposal-Thai].

  • U+0E47 MAITAIKHU and U+0E4C THANTHAKHAT are commonly used for words in everyday communication
  • U+0E4D NIKHAHIT is included because of its use to decompose U+0E33 THAI CHARACTER SARA AM, which is in common use. However, NIKHAHIT may also be used by itself.

A fourth above diacritic, U+0E4E YAMAKKAN, has been excluded from the Root Zone LGR repertoire because it is rarely used in Modern Thai or even in older Pali manuscripts; it is more common to replace it with U+0E3A PHINTHU, a below diacritic, which has been given the tag “bd”. Moreover, excluding U+0E4E YAMAKKAN also eliminates the chance of confusion between U+0E4E YAMAKKAN and U+0E4C THANTHAKHAT. Both look similar, are always placed at the same position in the word cell, and they are normally displayed in a small size.

Abbreviation Mark: The abbreviation mark (or ellipsis) U+0E2F PAIYANNOI should not be at the beginning position and must end the label. An exception to this rule has been provided for by a special sequence.

Repetition Mark: The repetition mark U+0E46 MAIYAMOK repeats anything before it. Therefore, it should not be at the beginning position. The repetition mark must not be followed by any combining mark, or follow a leading vowel to prevent unstable rendering. A repetition mark may be repeated. A context rule has been defined to limit the repetition mark to acceptable context, however, some of the restrictions are taken care of by other rules, for example, the rule that leading vowel must be followed by a consonant.

Thai Digits: U+0E50 to U+0E59 are a set of Thai-specific digits. They are used in alternation with the European (common) digits.

Common Digits: U+0030 to U+0039 are the set of digits from the ASCII range.

Whole Label Evaluation (WLE) and Context Rules

Common Rules

The LGR includes the rules and actions to implement the following restrictions, some of which are mandated by the IDNA protocol. They are marked with ⍟ and included here by default.

  • 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].
  • Digit-mixing — no mixing between different digit sets (European and Thai digits) is allowed; implemented here as a WLE rule with associated action.

Default Actions

This LGR includes the complete set 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] and [150]. An additional action is triggered by mixed digit labels.

Thai-specific Rules

The rules provided in this LGR as described in Section 7 of [Proposal-Thai] reasonably restrict labels so that they conform to Thai syllable structure. These constraints are exclusively presented as context rules.

The rules are:

  • A leading-vowel must precede a consonant — See Section 7.2 in [Proposal-Thai]
  • A below-vowel must follow a consonant — See Section 7.3 in [Proposal-Thai]
  • An above-vowel must follow a consonant — See Section 7.3 in [Proposal-Thai]
  • A below diacritic must follow a consonant — See Section 7.3 in [Proposal-Thai]
  • An above-diacritic MAITAIKHU must follow a consonant — See Section 7.3 in [Proposal-Thai]
  • A vowel MAIHAN AKAT must be in between a consonant and either tone or consonant — See Section 7.4 in [Proposal-Thai]
  • A vowel SARA A can follow a consonant, a tone or a vowel SARA AA — See Section 7.5 in [Proposal-Thai]
  • A vowel SARA AA, or an above diacritic NIKHAHIT followed by a vowel SARA AA can follow a consonant or a tone — See Sections 7.6 and 7.9 in [Proposal-Thai]
  • A tone mark, THANTHAKHAT, NIKHAHIT can only follow a consonant, above-vowel or below-vowel — See section 7.7 and 7.8 in [Proposal-Thai]
  • An abbreviation mark, PAIYANNOI cannot be at the beginning of the label and must end it — rule SL1 for second level
  • A repetition mark, MAIYAMOK can precede a repetition mark, an independent vowel, or end of label; it cannot start a label — rule SL2 for second level

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 Thai Language was developed by Michel Suignard and Asmus Freytag, based on the Root Zone LGR for the Thai script and information contained or referenced therein; see [RZ-LGR-Thai]. Suitable extensions for the second level have been applied according to the [Guidelines] and with community input. As part of that process, features have been removed or modified as appropriate for the target language. The original proposal for a Root Zone LGR for the Thai script, that this LGR is based on, was developed by the Thai Generation Panel. For more information on methodology and contributors to the underlying Root Zone LGR, see Sections 4 and 8 in [Proposal-Thai], as well as [RZ-LGR-Overview].

Changes from Version Dated 15 December 2020

Language tag has been updated.

Changes from Version Dated 18 May 2021

Unicode Version has been updated.

Changes from Version Dated 25 October 2024

Adopted from the Second Level Reference LGR for the Thai Language [Ref-LGR-th-Thai] without normative changes.

References

The following general references are cited in this document:

[Guidelines]
ICANN, “Guidelines for Developing Reference LGRs for the Second Level”, (Los Angeles, California: ICANN, 27 May 2020), https://www.icann.org/en/system/files/files/lgr-guidelines-second-level-27may20-en.pdf
[Proposal-Thai]
Proposal for a Thai Script Root Zone LGR, 25 May 2017, https://www.icann.org/en/system/files/files/proposal-thai-lgr-25may17-en.pdf
[Ref-LGR-th-Thai]
ICANN, Second Level Reference Label Generation Rules for the Thai Language (th-Thai), 25 October 2024 (XML) https://www.icann.org/sites/default/files/packages/lgr/lgr-second-level-thai-language-25oct24-en.xml non-normative HTML presentation: https://www.icann.org/sites/default/files/packages/lgr/lgr-second-level-thai-language-25oct24-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
[RFC 8228]
A. Freytag, “Guidance on Designing Label Generation Rulesets (LGRs) Supporting Variant Labels”, RFC 8228, August 2017, https://www.rfc-editor.org/info/rfc8228
[RZ-LGR-Overview]
Integration Panel, “Root Zone Label Generation Rules (RZ LGR-5): Overview and Summary”, 26 May 2022 (PDF), https://www.icann.org/sites/default/files/lgr/rz-lgr-5-overview-26may22-en.pdf
[RZ-LGR-Thai]
ICANN, Root Zone Label Generation Rules for the Thai Script (und-Thai), 26 May 2022 (XML) https://www.icann.org/sites/default/files/lgr/rz-lgr-5-thai-script-26may22-en.xml
[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/

For references consulted particularly in designing the repertoire for the Thai Language for the second level please see details in the Table of References below.

Reference [0] refers to the Unicode Standard version in which corresponding code points were initially encoded. References [100] and [101] correspond to sources given in [Proposal-Thai] for justifying the inclusion of for the corresponding 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.

Repertoire

Glyph Code point Tags and context Variants
- U+002D HYPHEN-MINUS 0 HYPHEN-MINUS; Tagsc:Zyyy Contextnot hyphen-minus-disallowed
0 U+0030 DIGIT ZERO 0 DIGIT ZERO; TagCommon-digitTagsc:Zyyy ๐ U+0E50 blocked Thai digit variant
1 U+0031 DIGIT ONE 0 DIGIT ONE; TagCommon-digitTagsc:Zyyy ๑ U+0E51 blocked Thai digit variant
2 U+0032 DIGIT TWO 0 DIGIT TWO; TagCommon-digitTagsc:Zyyy ๒ U+0E52 blocked Thai digit variant
3 U+0033 DIGIT THREE 0 DIGIT THREE; TagCommon-digitTagsc:Zyyy ๓ U+0E53 blocked Thai digit variant
4 U+0034 DIGIT FOUR 0 DIGIT FOUR; TagCommon-digitTagsc:Zyyy ๔ U+0E54 blocked Thai digit variant
5 U+0035 DIGIT FIVE 0 DIGIT FIVE; TagCommon-digitTagsc:Zyyy ๕ U+0E55 blocked Thai digit variant
6 U+0036 DIGIT SIX 0 DIGIT SIX; TagCommon-digitTagsc:Zyyy ๖ U+0E56 blocked Thai digit variant
7 U+0037 DIGIT SEVEN 0 DIGIT SEVEN; TagCommon-digitTagsc:Zyyy ๗ U+0E57 blocked Thai digit variant
8 U+0038 DIGIT EIGHT 0 DIGIT EIGHT; TagCommon-digitTagsc:Zyyy ๘ U+0E58 blocked Thai digit variant
9 U+0039 DIGIT NINE 0 DIGIT NINE; TagCommon-digitTagsc:Zyyy ๙ U+0E59 blocked Thai digit variant
ก U+0E01 THAI CHARACTER KO KAI 0 100 101 Thai TagconsTagsc:Thai
ข U+0E02 THAI CHARACTER KHO KHAI 0 100 101 Thai TagconsTagsc:Thai
ฃ U+0E03 THAI CHARACTER KHO KHUAT 0 100 101 Thai TagconsTagsc:Thai
ค U+0E04 THAI CHARACTER KHO KHWAI 0 100 101 Thai TagconsTagsc:Thai
ฅ U+0E05 THAI CHARACTER KHO KHON 0 100 101 Thai TagconsTagsc:Thai
ฆ U+0E06 THAI CHARACTER KHO RAKHANG 0 100 101 Thai TagconsTagsc:Thai
ง U+0E07 THAI CHARACTER NGO NGU 0 100 101 Thai TagconsTagsc:Thai
จ U+0E08 THAI CHARACTER CHO CHAN 0 100 101 Thai TagconsTagsc:Thai
ฉ U+0E09 THAI CHARACTER CHO CHING 0 100 101 Thai TagconsTagsc:Thai
ช U+0E0A THAI CHARACTER CHO CHANG 0 100 101 Thai TagconsTagsc:Thai
ซ U+0E0B THAI CHARACTER SO SO 0 100 101 Thai TagconsTagsc:Thai
ฌ U+0E0C THAI CHARACTER CHO CHOE 0 100 101 Thai TagconsTagsc:Thai
ญ U+0E0D THAI CHARACTER YO YING 0 100 101 Thai TagconsTagsc:Thai
ฎ U+0E0E THAI CHARACTER DO CHADA 0 100 101 Thai TagconsTagsc:Thai
ฏ U+0E0F THAI CHARACTER TO PATAK 0 100 101 Thai TagconsTagsc:Thai
ฐ U+0E10 THAI CHARACTER THO THAN 0 100 101 Thai TagconsTagsc:Thai
ฑ U+0E11 THAI CHARACTER THO NANGMONTHO 0 100 101 Thai TagconsTagsc:Thai
ฒ U+0E12 THAI CHARACTER THO PHUTHAO 0 100 101 Thai TagconsTagsc:Thai
ณ U+0E13 THAI CHARACTER NO NEN 0 100 101 Thai TagconsTagsc:Thai
ด U+0E14 THAI CHARACTER DO DEK 0 100 101 Thai TagconsTagsc:Thai
ต U+0E15 THAI CHARACTER TO TAO 0 100 101 Thai TagconsTagsc:Thai
ถ U+0E16 THAI CHARACTER THO THUNG 0 100 101 Thai TagconsTagsc:Thai
ท U+0E17 THAI CHARACTER THO THAHAN 0 100 101 Thai TagconsTagsc:Thai
ธ U+0E18 THAI CHARACTER THO THONG 0 100 101 Thai TagconsTagsc:Thai
น U+0E19 THAI CHARACTER NO NU 0 100 101 Thai TagconsTagsc:Thai
บ U+0E1A THAI CHARACTER BO BAIMAI 0 100 101 Thai TagconsTagsc:Thai
ป U+0E1B THAI CHARACTER PO PLA 0 100 101 Thai TagconsTagsc:Thai
ผ U+0E1C THAI CHARACTER PHO PHUNG 0 100 101 Thai TagconsTagsc:Thai
ฝ U+0E1D THAI CHARACTER FO FA 0 100 101 Thai TagconsTagsc:Thai
พ U+0E1E THAI CHARACTER PHO PHAN 0 100 101 Thai TagconsTagsc:Thai
ฟ U+0E1F THAI CHARACTER FO FAN 0 100 101 Thai TagconsTagsc:Thai
ภ U+0E20 THAI CHARACTER PHO SAMPHAO 0 100 101 Thai TagconsTagsc:Thai
ม U+0E21 THAI CHARACTER MO MA 0 100 101 Thai TagconsTagsc:Thai
ย U+0E22 THAI CHARACTER YO YAK 0 100 101 Thai TagconsTagsc:Thai
ร U+0E23 THAI CHARACTER RO RUA 0 100 101 Thai TagconsTagsc:Thai
ฤ U+0E24 THAI CHARACTER RU 0 100 101 Thai Tagfv3Tagsc:Thai
ฤๅ U+0E24U+0E45 sequence of 2 THAI CHARACTER RU + THAI CHARACTER LAKKHANGYAO 0 100 101 fv2, Thai
ล U+0E25 THAI CHARACTER LO LING 0 100 101 Thai TagconsTagsc:Thai
ฦ U+0E26 THAI CHARACTER LU 0 100 101 Thai Tagfv3Tagsc:Thai
ฦๅ U+0E26U+0E45 sequence of 2 THAI CHARACTER LU + THAI CHARACTER LAKKHANGYAO 0 100 101 fv2, Thai
ว U+0E27 THAI CHARACTER WO WAEN 0 100 101 Thai TagconsTagsc:Thai
ศ U+0E28 THAI CHARACTER SO SALA 0 100 101 Thai TagconsTagsc:Thai
ษ U+0E29 THAI CHARACTER SO RUSI 0 100 101 Thai TagconsTagsc:Thai
ส U+0E2A THAI CHARACTER SO SUA 0 100 101 Thai TagconsTagsc:Thai
ห U+0E2B THAI CHARACTER HO HIP 0 100 101 Thai TagconsTagsc:Thai
ฬ U+0E2C THAI CHARACTER LO CHULA 0 100 101 Thai TagconsTagsc:Thai
อ U+0E2D THAI CHARACTER O ANG 0 100 101 Thai TagconsTagsc:Thai
ฮ U+0E2E THAI CHARACTER HO NOKHUK 0 100 101 Thai TagconsTagsc:Thai
ฯ U+0E2F THAI CHARACTER PAIYANNOI 0 100 101 Thai TagabbrTagsc:Thai Contextfollows-any-precedes-end
ฯลฯ U+0E2FU+0E25U+0E2F sequence of 3 THAI CHARACTER PAIYANNOI + THAI CHARACTER LO LING + THAI CHARACTER PAIYANNOI 0 100 101 Thai Contextfollows-any-precedes-end
ะ U+0E30 THAI CHARACTER SARA A 0 100 101 Thai Tagfv1Tagsc:Thai Contextfollow-consonant-tone-sara-aa
ั U+0E31 THAI CHARACTER MAI HAN-AKAT 0 100 101 Thai TagavTagsc:Thai Contextbetween-consonant-and-ct
า U+0E32 THAI CHARACTER SARA AA 0 100 101 Thai Tagfv1Tagsara-aaTagsc:Thai Contextfollows-consonant-tone
ิ U+0E34 THAI CHARACTER SARA I 0 100 101 Thai TagavTagsc:Thai Contextfollows-consonant
ี U+0E35 THAI CHARACTER SARA II 0 100 101 Thai TagavTagsc:Thai Contextfollows-consonant
ึ U+0E36 THAI CHARACTER SARA UE 0 100 101 Thai TagavTagsc:Thai Contextfollows-consonant
ื U+0E37 THAI CHARACTER SARA UEE 0 100 101 Thai TagavTagsc:Thai Contextfollows-consonant
ุ U+0E38 THAI CHARACTER SARA U 0 100 101 Thai TagbvTagsc:Thai Contextfollows-consonant
ู U+0E39 THAI CHARACTER SARA UU 0 100 101 Thai TagbvTagsc:Thai Contextfollows-consonant
ฺ U+0E3A THAI CHARACTER PHINTHU 0 100 101 = phinthu; Thai TagbdTagsc:Thai Contextfollows-consonant
เ U+0E40 THAI CHARACTER SARA E 0 100 101 Thai TaglvTagsc:Thai Contextprecedes-consonant
แ U+0E41 THAI CHARACTER SARA AE 0 100 101 Thai TaglvTagsc:Thai Contextprecedes-consonant
โ U+0E42 THAI CHARACTER SARA O 0 100 101 Thai TaglvTagsc:Thai Contextprecedes-consonant
ใ U+0E43 THAI CHARACTER SARA AI MAIMUAN 0 100 101 Thai TaglvTagsc:Thai Contextprecedes-consonant
ไ U+0E44 THAI CHARACTER SARA AI MAIMALAI 0 100 101 Thai TaglvTagsc:Thai Contextprecedes-consonant
ๆ U+0E46 THAI CHARACTER MAIYAMOK 0 100 101 Thai TagrepTagsc:Thai Contextfollows-any-precedes-rep-cons-lv-end
็ U+0E47 THAI CHARACTER MAITAIKHU 0 100 101 = maitaikhu; Thai TagadTagsc:Thai Contextfollows-consonant
่ U+0E48 THAI CHARACTER MAI EK 0 100 101 Thai Tagsc:ThaiTagtone Contextfollows-consonant-av-bv
้ U+0E49 THAI CHARACTER MAI THO 0 100 101 Thai Tagsc:ThaiTagtone Contextfollows-consonant-av-bv
๊ U+0E4A THAI CHARACTER MAI TRI 0 100 101 Thai Tagsc:ThaiTagtone Contextfollows-consonant-av-bv
๋ U+0E4B THAI CHARACTER MAI CHATTAWA 0 100 101 Thai Tagsc:ThaiTagtone Contextfollows-consonant-av-bv
์ U+0E4C THAI CHARACTER THANTHAKHAT 0 100 101 = thanthakhat; Thai TagadTagsc:Thai Contextfollows-consonant-av-bv
ํ U+0E4D THAI CHARACTER NIKHAHIT 0 100 101 = nikhahit; Thai TagadTagsc:Thai Contextfollows-consonant-av-bv
ํา U+0E4DU+0E32 sequence of 2 THAI CHARACTER NIKHAHIT + THAI CHARACTER SARA AA 0 100 101 = sara am sequence; Thai Contextfollows-consonant-tone
๐ U+0E50 THAI DIGIT ZERO 0 THAI DIGIT ZERO Tagsc:ThaiTagThai-digit 0 U+0030 blocked ASCII digit variant
๑ U+0E51 THAI DIGIT ONE 0 THAI DIGIT ONE Tagsc:ThaiTagThai-digit 1 U+0031 blocked ASCII digit variant
๒ U+0E52 THAI DIGIT TWO 0 THAI DIGIT TWO Tagsc:ThaiTagThai-digit 2 U+0032 blocked ASCII digit variant
๓ U+0E53 THAI DIGIT THREE 0 THAI DIGIT THREE Tagsc:ThaiTagThai-digit 3 U+0033 blocked ASCII digit variant
๔ U+0E54 THAI DIGIT FOUR 0 THAI DIGIT FOUR Tagsc:ThaiTagThai-digit 4 U+0034 blocked ASCII digit variant
๕ U+0E55 THAI DIGIT FIVE 0 THAI DIGIT FIVE Tagsc:ThaiTagThai-digit 5 U+0035 blocked ASCII digit variant
๖ U+0E56 THAI DIGIT SIX 0 THAI DIGIT SIX Tagsc:ThaiTagThai-digit 6 U+0036 blocked ASCII digit variant
๗ U+0E57 THAI DIGIT SEVEN 0 THAI DIGIT SEVEN Tagsc:ThaiTagThai-digit 7 U+0037 blocked ASCII digit variant
๘ U+0E58 THAI DIGIT EIGHT 0 THAI DIGIT EIGHT Tagsc:ThaiTagThai-digit 8 U+0038 blocked ASCII digit variant
๙ U+0E59 THAI DIGIT NINE 0 THAI DIGIT NINE Tagsc:ThaiTagThai-digit 9 U+0039 blocked ASCII digit variant

Variants

Code points grouped into sets of mutual variants. Every member of a set produces the same set of variant labels, so a registration of one has implications for all the others. Sets of a single member are omitted, as are the identity mappings RFC 7940 requires each member to declare.

List
10 variant sets, containing 20 variants.

Character classes

Named sets of code points that the rules below refer to.

NameDefinition
above-vowel {tag av} Any Thai above vowel
below-vowel {tag bv} Any Thai below vowel
consonant {tag cons} Any Thai consonant
leading-vowel {tag lv} Any Thai leading vowel
repetition {tag rep} The Thai repetition mark, MAIYAMOK
sara-aa {tag sara-aa} Thai SARA AA
tone {tag tone} Any Thai tone mark
c-av-bv ({consonant} ∪ {above-vowel} ∪ {below-vowel}) Any Thai consonant, vowel-above or vowel-below
ct ({consonant} ∪ {tone}) Any Thai consonant or tone mark
ctaa ({consonant} ∪ {tone} ∪ {sara-aa}) Any Thai consonant, tone or sara-aa
common-digits {tag Common-digit} Digits from the ASCII range MSR default
thai-digits {tag Thai-digit} Thai digits

Rules

Conditions evaluated against a whole label, or against the context around a single code point. The notation borrows from regular expressions: ^ and $ anchor to the start and end of a label, . matches any code point, (?= ) and (?<= ) look ahead and behind, and * and + repeat. Two symbols are specific to rulesets: ◆ is the code point being tested, and ⟨name⟩ refers to another rule.

leading-combining-mark MSR default 150

RFC 5891 restrictions on placement of combining marks

^ ({gc:Mn} ∪ {gc:Mc})
Structure
  • ^ start
  • ({gc:Mn} ∪ {gc:Mc}) union
    • {gc:Mn} class
    • {gc:Mc} class
Referenced by 1 definition
  • action 1 (invalid)

hyphen-minus-disallowed MSR default 150

RFC 5891 restrictions on placement of U+002D HYPHEN-MINUS

( ( (?<= ^ ) ◆ ) │ ( ◆ (?= $ ) ) │ ( (?<= ^ . . U+002D ) ◆ ) )
Structure
  • ( ( (?<= ^ ) ◆ ) │ ( ◆ (?= $ ) ) │ ( (?<= ^ . . U+002D ) ◆ ) ) choice
    • (?<= ^ ) ◆ rule no leading hyphen
      • (?<= ^ ) look-behind
        • ^ start
      • ◆ anchor
    • ◆ (?= $ ) rule no trailing hyphen
      • ◆ anchor
      • (?= $ ) look-ahead
        • $ end
    • (?<= ^ . . U+002D ) ◆ rule no consecutive hyphens in third and fourth position in the label
      • (?<= ^ . . U+002D ) look-behind
        • ^ start
        • . any
        • . any
        • U+002D char hyphen-minus
      • ◆ anchor
Referenced by 1 definition
  • negative context of U+002D

precedes-consonant

WLE 7.2: check if current cp is preceding a consonant

◆ (?= {consonant} )
Structure
  • ◆ anchor
  • (?= {consonant} ) look-ahead
    • {consonant} class
Referenced by 5 definitions
  • context of U+0E40
  • context of U+0E41
  • context of U+0E42
  • context of U+0E43
  • context of U+0E44

follows-consonant

WLE 7.3: check if current cp is following a consonant

(?<= {consonant} ) ◆
Structure
  • (?<= {consonant} ) look-behind
    • {consonant} class
  • ◆ anchor
Referenced by 8 definitions
  • context of U+0E34
  • context of U+0E35
  • context of U+0E36
  • context of U+0E37
  • context of U+0E38
  • context of U+0E39
  • context of U+0E3A
  • context of U+0E47

between-consonant-and-ct

WLE 7.4: check if current cp is in between a consonant and either tone or consonant

(?<= {consonant} ) ◆ (?= {ct} )
Structure
  • (?<= {consonant} ) look-behind
    • {consonant} class
  • ◆ anchor
  • (?= {ct} ) look-ahead
    • {ct} class
Referenced by 1 definition
  • context of U+0E31

follow-consonant-tone-sara-aa

WLE 7.5: U+0E30 THAI CHARACTER SARA A can follow a consonant, a tone or U+0E32 THAI CHARACTER SARA AA

(?<= {ctaa} ) ◆
Structure
  • (?<= {ctaa} ) look-behind
    • {ctaa} class
  • ◆ anchor
Referenced by 1 definition
  • context of U+0E30

follows-consonant-tone

WLE 7.6, 7.9: check if current cp is following a consonant or a tone

(?<= {ct} ) ◆
Structure
  • (?<= {ct} ) look-behind
    • {ct} class
  • ◆ anchor
Referenced by 2 definitions
  • context of U+0E32
  • context of U+0E4D U+0E32

follows-consonant-av-bv

WLE 7.7, 7.8: A tone-mark, THANTHAKHAT, NIKAHIT can only follow a consonant, above-vowel or below-vowel

(?<= {c-av-bv} ) ◆
Structure
  • (?<= {c-av-bv} ) look-behind
    • {c-av-bv} class
  • ◆ anchor
Referenced by 6 definitions
  • context of U+0E48
  • context of U+0E49
  • context of U+0E4A
  • context of U+0E4B
  • context of U+0E4C
  • context of U+0E4D

follows-any-precedes-end 102

WLE SL1: An abbreviation mark, PAIYANNOI cannot be at the beginning of the label and must end it

(?<= . ) ◆ (?= $ )
Structure
  • (?<= . ) look-behind
    • . any
  • ◆ anchor
  • (?= $ ) look-ahead
    • $ end
Referenced by 2 definitions
  • context of U+0E2F
  • context of U+0E2F U+0E25 U+0E2F

follows-any-precedes-rep-cons-lv-end 102

WLE SL2: A repetition mark, MAIYAMOK cannot be at the beginning of the label and must be followed by itself, a consonat or a leading vowel

(?<= . ) ◆ (?= ( {consonant} │ {repetition} │ {leading-vowel} │ $ ) )
Structure
  • (?<= . ) look-behind
    • . any
  • ◆ anchor
  • (?= ( {consonant} │ {repetition} │ {leading-vowel} │ $ ) ) look-ahead
    • ( {consonant} │ {repetition} │ {leading-vowel} │ $ ) choice
      • {consonant} class
      • {repetition} class
      • {leading-vowel} class
      • $ end
Referenced by 1 definition
  • context of U+0E46

digit-mixing

restrictions on mixing digits

( ( {common-digits} .* {thai-digits} ) │ ( {thai-digits} .* {common-digits} ) )
Structure
  • ( ( {common-digits} .* {thai-digits} ) │ ( {thai-digits} .* {common-digits} ) ) choice
    • {common-digits} .* {thai-digits} rule
      • {common-digits} class
      • .* any
      • {thai-digits} class
    • {thai-digits} .* {common-digits} rule
      • {thai-digits} class
      • .* any
      • {common-digits} class
Referenced by 1 definition
  • action 2 (invalid)

Actions

Actions are evaluated in the order shown. The first action whose conditions match determines the disposition of the label.

# Disposition Conditions
1 invalid label matches leading-combining-mark 150 labels with leading combining marks are invalid MSR default
2 invalid label matches digit-mixing a label violating the restriction on digit mixing is invalid
3 invalid any variant is out-of-repertoire-var any variant label with a code point out of repertoire is invalid MSR default
4 blocked any variant is blocked any variant label containing blocked variants is blocked MSR default
5 allocatable all variants are allocatable variant labels with all variants allocatable are allocatable MSR default
6 valid any label default catch all (default action) MSR default

References

RefSource
0 The Unicode Standard, Version 1.1
Any code point originally encoded in Unicode Version 1.1
100 Thai Industrial Standard (TIS) 1566-2541(1988) https://www.ratchakitcha.soc.go.th/DATA/PDF/2542/E/088/9.PDF
101 Computers and the Thai Language https://lexitron.nectec.or.th/KM_HL5001/file_HL5001/Paper/Inter%20Journal/krrn_52085.pdf
102 Thai Generation Panel experts, private communication during review for second level
150 RFC 5891, Internationalized Domain Names in Applications (IDNA): Protocol https://tools.ietf.org/html/rfc5891