Reference LGR for language: Thai (th) | lgr-second-level-thai-language-25oct24-en

This document is mechanically formatted from the above XML file for the LGR. It provides additional summary data and explanatory text. The XML file remains the sole normative specification of the LGR.

Date | 2024-10-25
LGR Version | 3 (Second Level Reference LGR)
Language | th (Thai Language)
Unicode Version | 11.0.0

# 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

## 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 ํา was defined to replace the disallowed U+0E33 ำ 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 ๅ LAKKHANGYAO from appearing in any context other than these sequences. Accordingly, while U+0E45 ๅ 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 0 to U+0039 9; Thai digits, U+0E50 ๐ to U+0E59 ๙; U+002D - HYPHEN-MINUS; the abbreviation mark U+0E2F ฯ THAI CHARACTER PAIYANNOI; and the repetition mark U+0E46 ๆ 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 ำ 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 ฯ 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 ๆ 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 ๐ to U+0E59 ๙ are a set of Thai-specific digits. They are used in alternation with the European (common) digits.

Common Digits: U+0030 0 to U+0039 9 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

## Repertoire Summary

Number of elements in repertoire | 95
Number of code points for each script |
Thai | 80
Common | 11
Number of code points | 91
Number of sequences | 4
Longest code point sequence | 3
Code points defined via sequence | 1

## Repertoire by Code Point

The following table lists the repertoire by code point (or code point sequence). The data in the Script and Name column are extracted from the Unicode character database. Where a comment in the original LGR is equal to the character name, it has been suppressed.

Some code points that may be part of a valid label under this LGR only occur as part of one or more sequences. Such code points are not listed individually in the table.

For any code point or sequence for which a variant is defined, additional information is provided in the Variants column. See also the legend provided below the table.

Code Point | Glyph | Script | Name | Ref | Tags | Required Context | Variants | Comment
--- | --- | --- | --- | --- | --- | --- | --- | ---
U+002D | - | Common | HYPHEN-MINUS | [0] |  | not: hyphen-minus-disallowed |  | ⍟
U+0030 | 0 | Common | DIGIT ZERO | [0] | Common-digit |  | set 1 | ⍟
U+0031 | 1 | Common | DIGIT ONE | [0] | Common-digit |  | set 2 | ⍟
U+0032 | 2 | Common | DIGIT TWO | [0] | Common-digit |  | set 3 | ⍟
U+0033 | 3 | Common | DIGIT THREE | [0] | Common-digit |  | set 4 | ⍟
U+0034 | 4 | Common | DIGIT FOUR | [0] | Common-digit |  | set 5 | ⍟
U+0035 | 5 | Common | DIGIT FIVE | [0] | Common-digit |  | set 6 | ⍟
U+0036 | 6 | Common | DIGIT SIX | [0] | Common-digit |  | set 7 | ⍟
U+0037 | 7 | Common | DIGIT SEVEN | [0] | Common-digit |  | set 8 | ⍟
U+0038 | 8 | Common | DIGIT EIGHT | [0] | Common-digit |  | set 9 | ⍟
U+0039 | 9 | Common | DIGIT NINE | [0] | Common-digit |  | set 10 | ⍟
U+0E01 | ก | Thai | THAI CHARACTER KO KAI | [0], [100], [101] | cons |  |  | Thai
U+0E02 | ข | Thai | THAI CHARACTER KHO KHAI | [0], [100], [101] | cons |  |  | Thai
U+0E03 | ฃ | Thai | THAI CHARACTER KHO KHUAT | [0], [100], [101] | cons |  |  | Thai
U+0E04 | ค | Thai | THAI CHARACTER KHO KHWAI | [0], [100], [101] | cons |  |  | Thai
U+0E05 | ฅ | Thai | THAI CHARACTER KHO KHON | [0], [100], [101] | cons |  |  | Thai
U+0E06 | ฆ | Thai | THAI CHARACTER KHO RAKHANG | [0], [100], [101] | cons |  |  | Thai
U+0E07 | ง | Thai | THAI CHARACTER NGO NGU | [0], [100], [101] | cons |  |  | Thai
U+0E08 | จ | Thai | THAI CHARACTER CHO CHAN | [0], [100], [101] | cons |  |  | Thai
U+0E09 | ฉ | Thai | THAI CHARACTER CHO CHING | [0], [100], [101] | cons |  |  | Thai
U+0E0A | ช | Thai | THAI CHARACTER CHO CHANG | [0], [100], [101] | cons |  |  | Thai
U+0E0B | ซ | Thai | THAI CHARACTER SO SO | [0], [100], [101] | cons |  |  | Thai
U+0E0C | ฌ | Thai | THAI CHARACTER CHO CHOE | [0], [100], [101] | cons |  |  | Thai
U+0E0D | ญ | Thai | THAI CHARACTER YO YING | [0], [100], [101] | cons |  |  | Thai
U+0E0E | ฎ | Thai | THAI CHARACTER DO CHADA | [0], [100], [101] | cons |  |  | Thai
U+0E0F | ฏ | Thai | THAI CHARACTER TO PATAK | [0], [100], [101] | cons |  |  | Thai
U+0E10 | ฐ | Thai | THAI CHARACTER THO THAN | [0], [100], [101] | cons |  |  | Thai
U+0E11 | ฑ | Thai | THAI CHARACTER THO NANGMONTHO | [0], [100], [101] | cons |  |  | Thai
U+0E12 | ฒ | Thai | THAI CHARACTER THO PHUTHAO | [0], [100], [101] | cons |  |  | Thai
U+0E13 | ณ | Thai | THAI CHARACTER NO NEN | [0], [100], [101] | cons |  |  | Thai
U+0E14 | ด | Thai | THAI CHARACTER DO DEK | [0], [100], [101] | cons |  |  | Thai
U+0E15 | ต | Thai | THAI CHARACTER TO TAO | [0], [100], [101] | cons |  |  | Thai
U+0E16 | ถ | Thai | THAI CHARACTER THO THUNG | [0], [100], [101] | cons |  |  | Thai
U+0E17 | ท | Thai | THAI CHARACTER THO THAHAN | [0], [100], [101] | cons |  |  | Thai
U+0E18 | ธ | Thai | THAI CHARACTER THO THONG | [0], [100], [101] | cons |  |  | Thai
U+0E19 | น | Thai | THAI CHARACTER NO NU | [0], [100], [101] | cons |  |  | Thai
U+0E1A | บ | Thai | THAI CHARACTER BO BAIMAI | [0], [100], [101] | cons |  |  | Thai
U+0E1B | ป | Thai | THAI CHARACTER PO PLA | [0], [100], [101] | cons |  |  | Thai
U+0E1C | ผ | Thai | THAI CHARACTER PHO PHUNG | [0], [100], [101] | cons |  |  | Thai
U+0E1D | ฝ | Thai | THAI CHARACTER FO FA | [0], [100], [101] | cons |  |  | Thai
U+0E1E | พ | Thai | THAI CHARACTER PHO PHAN | [0], [100], [101] | cons |  |  | Thai
U+0E1F | ฟ | Thai | THAI CHARACTER FO FAN | [0], [100], [101] | cons |  |  | Thai
U+0E20 | ภ | Thai | THAI CHARACTER PHO SAMPHAO | [0], [100], [101] | cons |  |  | Thai
U+0E21 | ม | Thai | THAI CHARACTER MO MA | [0], [100], [101] | cons |  |  | Thai
U+0E22 | ย | Thai | THAI CHARACTER YO YAK | [0], [100], [101] | cons |  |  | Thai
U+0E23 | ร | Thai | THAI CHARACTER RO RUA | [0], [100], [101] | cons |  |  | Thai
U+0E24 | ฤ | Thai | THAI CHARACTER RU | [0], [100], [101] | fv3 |  |  | Thai
U+0E24 U+0E45 | ฤๅ | {Thai} | THAI CHARACTER RU + THAI CHARACTER LAKKHANGYAO | [0], [100], [101] | [fv3] + U+0E45 |  |  | fv2, Thai
U+0E25 | ล | Thai | THAI CHARACTER LO LING | [0], [100], [101] | cons |  |  | Thai
U+0E26 | ฦ | Thai | THAI CHARACTER LU | [0], [100], [101] | fv3 |  |  | Thai
U+0E26 U+0E45 | ฦๅ | {Thai} | THAI CHARACTER LU + THAI CHARACTER LAKKHANGYAO | [0], [100], [101] | [fv3] + U+0E45 |  |  | fv2, Thai
U+0E27 | ว | Thai | THAI CHARACTER WO WAEN | [0], [100], [101] | cons |  |  | Thai
U+0E28 | ศ | Thai | THAI CHARACTER SO SALA | [0], [100], [101] | cons |  |  | Thai
U+0E29 | ษ | Thai | THAI CHARACTER SO RUSI | [0], [100], [101] | cons |  |  | Thai
U+0E2A | ส | Thai | THAI CHARACTER SO SUA | [0], [100], [101] | cons |  |  | Thai
U+0E2B | ห | Thai | THAI CHARACTER HO HIP | [0], [100], [101] | cons |  |  | Thai
U+0E2C | ฬ | Thai | THAI CHARACTER LO CHULA | [0], [100], [101] | cons |  |  | Thai
U+0E2D | อ | Thai | THAI CHARACTER O ANG | [0], [100], [101] | cons |  |  | Thai
U+0E2E | ฮ | Thai | THAI CHARACTER HO NOKHUK | [0], [100], [101] | cons |  |  | Thai
U+0E2F | ฯ | Thai | THAI CHARACTER PAIYANNOI | [0], [100], [101] | abbr | follows-any-precedes-end |  | Thai
U+0E2F U+0E25 U+0E2F | ฯลฯ | {Thai} | THAI CHARACTER PAIYANNOI + THAI CHARACTER LO LING + THAI CHARACTER PAIYANNOI | [0], [100], [101] | [abbr] + [cons] + [abbr] | follows-any-precedes-end |  | Thai
U+0E30 | ะ | Thai | THAI CHARACTER SARA A | [0], [100], [101] | fv1 | follow-consonant-tone-sara-aa |  | Thai
U+0E31 | ั | Thai | THAI CHARACTER MAI HAN-AKAT | [0], [100], [101] | av | between-consonant-and-ct |  | Thai
U+0E32 | า | Thai | THAI CHARACTER SARA AA | [0], [100], [101] | fv1, sara-aa | follows-consonant-tone |  | Thai
U+0E34 | ิ | Thai | THAI CHARACTER SARA I | [0], [100], [101] | av | follows-consonant |  | Thai
U+0E35 | ี | Thai | THAI CHARACTER SARA II | [0], [100], [101] | av | follows-consonant |  | Thai
U+0E36 | ึ | Thai | THAI CHARACTER SARA UE | [0], [100], [101] | av | follows-consonant |  | Thai
U+0E37 | ื | Thai | THAI CHARACTER SARA UEE | [0], [100], [101] | av | follows-consonant |  | Thai
U+0E38 | ุ | Thai | THAI CHARACTER SARA U | [0], [100], [101] | bv | follows-consonant |  | Thai
U+0E39 | ู | Thai | THAI CHARACTER SARA UU | [0], [100], [101] | bv | follows-consonant |  | Thai
U+0E3A | ฺ | Thai | THAI CHARACTER PHINTHU | [0], [100], [101] | bd | follows-consonant |  | = phinthu; Thai
U+0E40 | เ | Thai | THAI CHARACTER SARA E | [0], [100], [101] | lv | precedes-consonant |  | Thai
U+0E41 | แ | Thai | THAI CHARACTER SARA AE | [0], [100], [101] | lv | precedes-consonant |  | Thai
U+0E42 | โ | Thai | THAI CHARACTER SARA O | [0], [100], [101] | lv | precedes-consonant |  | Thai
U+0E43 | ใ | Thai | THAI CHARACTER SARA AI MAIMUAN | [0], [100], [101] | lv | precedes-consonant |  | Thai
U+0E44 | ไ | Thai | THAI CHARACTER SARA AI MAIMALAI | [0], [100], [101] | lv | precedes-consonant |  | Thai
U+0E46 | ๆ | Thai | THAI CHARACTER MAIYAMOK | [0], [100], [101] | rep | follows-any-precedes-rep-cons-lv-end |  | Thai
U+0E47 | ็ | Thai | THAI CHARACTER MAITAIKHU | [0], [100], [101] | ad | follows-consonant |  | = maitaikhu; Thai
U+0E48 | ่ | Thai | THAI CHARACTER MAI EK | [0], [100], [101] | tone | follows-consonant-av-bv |  | Thai
U+0E49 | ้ | Thai | THAI CHARACTER MAI THO | [0], [100], [101] | tone | follows-consonant-av-bv |  | Thai
U+0E4A | ๊ | Thai | THAI CHARACTER MAI TRI | [0], [100], [101] | tone | follows-consonant-av-bv |  | Thai
U+0E4B | ๋ | Thai | THAI CHARACTER MAI CHATTAWA | [0], [100], [101] | tone | follows-consonant-av-bv |  | Thai
U+0E4C | ์ | Thai | THAI CHARACTER THANTHAKHAT | [0], [100], [101] | ad | follows-consonant-av-bv |  | = thanthakhat; Thai
U+0E4D | ํ | Thai | THAI CHARACTER NIKHAHIT | [0], [100], [101] | ad | follows-consonant-av-bv |  | = nikhahit; Thai
U+0E4D U+0E32 | ํา | {Thai} | THAI CHARACTER NIKHAHIT + THAI CHARACTER SARA AA | [0], [100], [101] | [ad] + [fv1, sara-aa] | follows-consonant-tone |  | = sara am sequence; Thai
U+0E50 | ๐ | Thai | THAI DIGIT ZERO | [0] | Thai-digit |  | set 1 |
U+0E51 | ๑ | Thai | THAI DIGIT ONE | [0] | Thai-digit |  | set 2 |
U+0E52 | ๒ | Thai | THAI DIGIT TWO | [0] | Thai-digit |  | set 3 |
U+0E53 | ๓ | Thai | THAI DIGIT THREE | [0] | Thai-digit |  | set 4 |
U+0E54 | ๔ | Thai | THAI DIGIT FOUR | [0] | Thai-digit |  | set 5 |
U+0E55 | ๕ | Thai | THAI DIGIT FIVE | [0] | Thai-digit |  | set 6 |
U+0E56 | ๖ | Thai | THAI DIGIT SIX | [0] | Thai-digit |  | set 7 |
U+0E57 | ๗ | Thai | THAI DIGIT SEVEN | [0] | Thai-digit |  | set 8 |
U+0E58 | ๘ | Thai | THAI DIGIT EIGHT | [0] | Thai-digit |  | set 9 |
U+0E59 | ๙ | Thai | THAI DIGIT NINE | [0] | Thai-digit |  | set 10 |

Legend

Throughout this LGR, a code point sequence may be annotated with a string in ALL CAPS that is constructed on the same principle as a name for a Unicode Named Sequence. No claim is made that a sequence thus annotated is in fact a named sequence, nor that the annotation in such case actually corresponds to the formal name of a named sequence.

Code Point
  A code point or code point sequence.
Glyph
  The shape displayed depends on the fonts available to your browser.
Script
  Shows the script property value from the Unicode Character Database. Combining marks may have the value Inherited and code points used with more than one script may have the value Common. Sequences are annotated with a set of all distinct script values.
Name
  Shows the character or sequence name from the Unicode Character Database. Named sequences are listed with their normative names, for ad-hoc sequences the individual names are shown separated by “+”.
Ref
  Links to the references associated with the code point or sequence, if any.
Tags
  LGR-defined tag values. Any tags matching the Unicode script property are suppressed in this view. For sequences, the tags for all member code points are shown in [] for information; sequences as such do not have tags.
Required Context
  Link to a rule defining the required context a code point or sequence must satisfy. If prefixed by “not:” identifies a context that must not occur.
Variants
  Link to the variant set the code point or sequence is a member of, except where a coded point or sequence maps only to itself, in which case the type of that mapping is listed.
Comment
  The comment as given in the XML file. However, if the comment for this row consists only of the code point or sequence name, it is suppressed in this view. By convention, comments starting with “=” denote an alias. If present, the symbol ⍟ marks a default item shared among a set of LGRs.

# Variants

## Variant Set Summary

Number of variant sets | 10
Largest variant set | 2
Variants by Type |
blocked 20

## Variant Sets

The following tables list all variant sets defined in this LGR, except for singleton sets. Each table lists all variant mapping pairs of the set; one per row. Mappings are assumed to be symmetric: each row documents both forward (→) and reverse (←) mapping directions. In each table, the mappings are sorted by Source value in ascending code point order; shading is used to group mappings from the same source code point or sequence.

Where the type of both forward and reverse mappings are the same, a single value is given in the Type column; otherwise the types for forward and reverse mappings, as well as comments and references, are listed above one another. For summary counts, both forward and reverse mappings are always counted separately.

In any LGR with variant specifications that are well behaved, all members within each variant set are defined as variants of each other; the mappings in each set are symmetric and transitive; and all variant sets are disjoint.

Common Legend

Source
  By convention, the smaller of the two code points in a variant mapping pair.
Target
  By convention, the larger of the two code points in a variant mapping pair.
Glyph
  The shape displayed for source or target depends on the fonts available to your browser.
→ - forward
  Indicates that Type, Ref and Comment apply to the mapping from source to target.
← - reverse
  Indicates that Type, Ref and Comment apply to the reverse mapping from target to source.
↔ - both
  Indicates that Type, Ref and Comment apply to both forward and reverse mapping.
Type
  The type of the variant mapping, including predefined variant types such as “allocatable” and “blocked”; or any that are defined specifically for this LGR.
Ref
  One or more reference IDs (optional). A “/” separates references for reverse / forward mappings, if different.
Comment
  A descriptive comment (optional). A “/” separates comments for reverse / forward mappings, if different.

### Variant Set 1 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0030 | 0 | 0E50 | ๐ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 2 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0031 | 1 | 0E51 | ๑ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 3 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0032 | 2 | 0E52 | ๒ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 4 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0033 | 3 | 0E53 | ๓ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 5 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0034 | 4 | 0E54 | ๔ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 6 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0035 | 5 | 0E55 | ๕ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 7 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0036 | 6 | 0E56 | ๖ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 8 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0037 | 7 | 0E57 | ๗ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 9 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0038 | 8 | 0E58 | ๘ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

### Variant Set 10 — 2 Members

Source | Glyph | Target | Glyph |  | Type | Ref | Comment
--- | --- | --- | --- | --- | --- | --- | ---
0039 | 9 | 0E59 | ๙ | ↔ | blocked |  | ASCII digit variant / Thai digit variant

# Classes, Rules and Actions

## Character Classes

Number of named classes | 12
Implicit (except script) | 5
Implicit 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
--- | --- | --- | --- | --- | ---
above-vowel | Tag=av | 5 | {0E31 0E34-0E37} |  | Any Thai above vowel
below-vowel | Tag=bv | 2 | {0E38-0E39} |  | Any Thai below vowel
consonant | Tag=cons | 44 | {0E01-0E23 0E25 0E27-0E2E} |  | Any Thai consonant
leading-vowel | Tag=lv | 5 | {0E40-0E44} |  | Any Thai leading vowel
repetition | Tag=rep | 1 | {0E46} |  | The Thai repetition mark, MAIYAMOK
sara-aa | Tag=sara-aa | 1 | {0E32} |  | Thai SARA AA
tone | Tag=tone | 4 | {0E48-0E4B} |  | Any Thai tone mark
c-av-bv | combined = [[:consonant:] ∪ [:above-vowel:] ∪ [:below-vowel:]] | 51 | {0E01-0E23 0E25 0E27-0E2E 0E31 0E34-0E39} |  | Any Thai consonant, vowel-above or vowel-below
ct | combined = [[:consonant:] ∪ [:tone:]] | 48 | {0E01-0E23 0E25 0E27-0E2E 0E48-0E4B} |  | Any Thai consonant or tone mark
ctaa | combined = [[:consonant:] ∪ [:tone:] ∪ [:sara-aa:]] | 49 | {0E01-0E23 0E25 0E27-0E2E 0E32 0E48-0E4B} |  | Any Thai consonant, tone or sara-aa
common-digits | Tag=Common-digit | 10 | {0030-0039} |  | Digits from the ASCII range ⍟
thai-digits | Tag=Thai-digit | 10 | {0E50-0E59} |  | Thai digits
implicit | Tag=abbr | 1 | {0E2F} |  | The character tagged as abbr
implicit | Tag=ad | 3 | {0E47 0E4C-0E4D} |  | Any character tagged as ad
implicit | Tag=bd | 1 | {0E3A} |  | The character tagged as bd
implicit | Tag=fv1 | 2 | {0E30 0E32} |  | Any character tagged as fv1
implicit | Tag=fv3 | 2 | {0E24 0E26} |  | Any character tagged as fv3
implicit | Tag=sc:Thai | 80 | {0E01-0E32 0E34-0E3A 0E40-0E44 0E46-0E4D 0E50-0E59} |  | Any character tagged as Thai
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.
Combined
  A named class defined by set operations on other classes using the following syntax:
[: :] - named or implicit character set
  Reference to a named character set [:name:] or an implicit character set [:tag:]. A leading “^” before name or tag indicates the set complement.
[&&, -, ^] - set operators
  Sets may be combined by set operators (&& = intersection, - = difference, ^ = symmetric difference) or concatenated (union).

## Whole label evaluation and context rules

Number of rules | 11
Used to trigger actions | 2
Used as context rule (C) | 9
Anchored context rules | 9

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 - HYPHEN-MINUS ⍟
precedes-consonant | `⚓︎ →([:consonant:])` |  | ✔ | C |  | WLE 7.2: check if current cp is preceding a consonant
follows-consonant | `([:consonant:])← ⚓︎` |  | ✔ | C |  | WLE 7.3: check if current cp is following a consonant
between-consonant-and-ct | `([:consonant:])← ⚓︎ →([:ct:])` |  | ✔ | C |  | WLE 7.4: check if current cp is in between a consonant and either tone or consonant
follow-consonant-tone-sara-aa | `([:ctaa:])← ⚓︎` |  | ✔ | C |  | WLE 7.5: U+0E30 ะ THAI CHARACTER SARA A can follow a consonant, a tone or U+0E32 า THAI CHARACTER SARA AA
follows-consonant-tone | `([:ct:])← ⚓︎` |  | ✔ | C |  | WLE 7.6, 7.9: check if current cp is following a consonant or a tone
follows-consonant-av-bv | `([:c-av-bv:])← ⚓︎` |  | ✔ | C |  | WLE 7.7, 7.8: A tone-mark, THANTHAKHAT, NIKAHIT can only follow a consonant, above-vowel or below-vowel
follows-any-precedes-end | `(.)← ⚓︎ →((end))` |  | ✔ | C | [102] | WLE SL1: An abbreviation mark, PAIYANNOI cannot be at the beginning of the label and must end it
follows-any-precedes-rep-cons-lv-end | `(.)← ⚓︎ →([:consonant:]|[:repetition:]|[:leading-vowel:]|(end))` |  | ✔ | C | [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
digit-mixing | `(([:common-digits:].*[:thai-digits:])|([:thai-digits:].*[:common-digits:]))` | ✔ |  |  |  | restrictions on mixing digits

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 (...|...).
^ or $ - start or end
  ^ matches the start of the label; $ matches the end of the label.
. - any code point
  . matches any code point.
*, +, ?, {n,m} - count operators
  * indicates 0 or more, + indicates one or more, and ? indicates up to one instance. {n,m} indicates at least n and at most m instances.
[: :] - named or implicit character set
  Reference to a named character set [:name:] or an implicit character set [:tag:]. A leading “^” before name or tag indicates the set complement.
[\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 (&& = intersection, - = difference, ^ = symmetric difference) or concatenated (union).
∅= - 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.
⍟ - 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 | [150] | labels with leading combining marks are invalid ⍟
2 | if label matches | digit-mixing | → | invalid |  | a label violating the restriction on digit mixing is invalid
3 | if at least one variant is in | {out-of-repertoire-var} | → | invalid |  | any variant label with a code point out of repertoire is invalid ⍟
4 | if at least one variant is in | {blocked} | → | blocked |  | any variant label containing blocked variants is blocked ⍟
5 | if each variant is in | {allocatable} | → | allocatable |  | variant labels with all variants allocatable are allocatable ⍟
6 | if any label (catch-all) |  | → | valid |  | catch all (default action) ⍟

Legend

{...} - variant type set
  In the “Rule/Variant Set” column, the notation {...} means a set of variant types.
⍟ - default action
  Actions marked with ⍟ are included by default and may or may not be triggered by any possible label under this LGR.

Note: The following variant types are used in one or more actions, but are not defined in this LGR: allocatable, out-of-repertoire-var. This is not necessarily an error.

# Table of References

The following lists the references cited for specific code points, variants, classes, rules or actions in this LGR. For General references refer to the References section in the Description.

[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