Root Zone LGR for script: Khmer (Khmr) rz-lgr-5-khmer-script-26may22-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 2022-05-26
LGR Version 5 (Root Zone LGR for the Khmer Script)
Language und-Khmr (Khmer Script)
Scope domain: "." (Root)
Unicode Version 11.0.0

Table of Contents


Root Zone Label Generation Rules for the Khmer Script


This file contains Label Generation Rules (LGR) for the Khmer script for the Root Zone. For more details on this LGR and additional background on the script see “Proposal for a Khmer Script Root Zone LGR” [Proposal-Khmer]. This file is one of a set of LGR files that together form an integrated LGR for the DNS Root Zone [RZ-LGR-5]. The format of this file follows [RFC 7940].


In addition to the 71 code points according to Section 5, “Repertoire”, in [Proposal-Khmer], two Khmer subscript consonant sequences have been defined. The repertoire only includes code points used by languages that are actively written in the Khmer script. The repertoire is based on [MSR-5], which is a subset of [Unicode 11.0].

As part of the Root Zone, this LGR includes neither decimal digits nor the HYPHEN-MINUS.

Each code point is tagged with the script or scripts with which the code point is used, one or more other character categories, and one or more references documenting sufficient justification for inclusion in the repertoire; see “References” below. Comments identify the language using the code point.


This LGR defines two Khmer consonants as variants of each other in their subscript form only. This is captured by a variant relation between the two subscript sequences, which are listed explicitly in the repertoire. See Section 6, “Variants” in [Proposal-Khmer],

Variant Disposition: All variants are of type “blocked”, making labels that differ only by these variants mutually exclusive: whichever label containing either of these variants is chosen earlier would be delegated, while any other equivalent label should be blocked.

This LGR does not define allocatable variants.

The specification of variants in the Root Zone LGR follows the guidelines in [RFC 8228].

Character Classes

Consonants: When more than one consonant occur together in the onset of a grapheme cluster, the additional consonants are written in subscript form, joined with the first consonant in the sequence. In Unicode, this is indicated by preceding each additional consonant with U+17D2 (្) KHMER SIGN COENG. Some consonants have been given the tag “base-only”; these do not take subscript form. Consonants can have light or strong pronunciation indicated by two shifter signs; additionally there are six signs for phonological modifications as discussed below. See Section 5.2, “Consonants” in [Proposal-Khmer].

Independent vowels: These occur independently and cannot combine with any of the marks including dependent vowels and signs. The use of a subscript form, while defined in Unicode, is not supported here. See Section 5.2, “Independent Vowels” in [Proposal-Khmer].

Dependent vowels: The 16 dependent vowels included in the Khmer LGR have been further classified into three subcategories namely dependent vowel 1, dependent vowel 2 and dependent vowel 3, see below. Dependent vowels must follow a consonant, shifter or the Robat sign. They cannot occur independently. See Section 5.3, “Dependent Vowels” in [Proposal-Khmer].

Shifters: the character U+17C9 (៉) KHMER SIGN MUUSIKATOAN is used with a subset of first series consonants, code points from this subset have been given the tag “series-one”. The character U+17CA (៊) KHMER SIGN TRIISAP is used with subset of second series consonants and with U+1794 (ប) KHMER LETTER BA. Code points from this subset have been given the tag “series-two”. The two characters are collectively known as consonant shifters and have been given the tag “shifter”. See Section 5.5, “Shifters” in [Proposal-Khmer] and reference [210].

Robat: The character U+17CC (៌) KHMER SIGN ROBAT has been given the tag “robat”. It follows consonants but unlike other signs may be followed by a dependent vowel. See Sections 5.3, “Dependent Vowels” and 5.4, “Signs” in [Proposal-Khmer].

Signs (Bantoc): The character U+17CB (់) KHMER SIGN BANTOC is used with a subset of consonants, that subset has been given the tag “series-three”, see Section 5.4, “Signs” in [Proposal-Khmer] and reference [205].

Signs (Yuukalepintu and Samyoksannya): The character U+17C8 (្) KHMER SIGN YUUKALEAPINTU is written after a consonant to indicate that it is to be followed by a short vowel and a glottal stop. The sign is used with all the consonants. The character U+17D0 (្) KHMER SIGN SAMYOKSANNYA is written above a consonant or a shifter to indicate that the syllable contains a particular short vowel. The sign is used with all the consonants or all the shifters. See Section 5.4, “Signs” in [Proposal-Khmer].

Signs (Nikahit and Reahmuk): The character U+17C6 (ំ) KHMER SIGN NIKAHIT is used with consonants and some dependent vowels. These dependent vowels have been given a tag “dependent-vowel-1” (see Sections 5.3 and 5.4 in [Proposal-Khmer]). The character U+17C7 (ះ) KHMER SIGN REAHMUK is used with consonants and some dependent vowels. These dependent vowels have been given a tag “dependent-vowel-2” (see Sections 5.3 and 5.4 in [Proposal-Khmer]).

Signs (Toandakhiat): The sign ្ KHMER SIGN TOANDAKHIAT (U+17CD) is written over a final consonant to indicate that it is unpronounced. It is used with all consonants or Khmer vowel SIGN I (U+17B7). The latter has been given a tag “dependent-vowel-3”. See Section 5.4, “Signs” in [Proposal-Khmer].

Whole Label Evaluation (WLE) and Context Rules

Default Whole Label Evaluation Rules and Actions

The LGR includes the set of required default WLE rules and actions applicable to the Root Zone and defined in [MSR-5]. They are marked with ⍟. The default prohibition on leading combining marks is equivalent to ensuring that a label only starts with a consonant or independent-vowel.

Khmer-specific Rules and Action

Rules provided in the LGR as described in Section 7 of [Proposal-Khmer] constrain possible labels so that they reasonably conform to Khmer syllable structure. These constraints are presented as context rules on the affected code points, except for the whole-label rule and associated action that enforce the limit on the number of consecutive subscripted consonants.

The rules are:

Methodology and Contributors

The Root Zone LGR for the Khmer script was developed by the Khmer Generation Panel. For methodology and contributors, see Sections 4 and 8 in [Proposal-Khmer], as well as [RZ-LGR-5-Overview].


The following general references are cited in this document:

Integration Panel, “Maximal Starting Repertoire — MSR-5 Overview and Rationale”, 24 June 2021
Khmer Generation Panel, “Proposal for Khmer Script Root Zone LGR”, 15 August 2016,
[RFC 7940]
Davies, K. and A. Freytag, “Representing Label Generation Rulesets Using XML”, RFC 7940, August 2016,
[RFC 8228]
A. Freytag, “Guidance on Designing Label Generation Rulesets (LGRs) Supporting Variant Labels”, RFC 8228, August 2017,
Integration Panel, “Root Zone Label Generation Rules (RZ LGR-5): Overview and Summary”, 26 May 2022,
Integration Panel, “Root Zone Label Generation Rules (RZ-LGR-5)”, 26 May 2022 (XML),
non-normative HTML presentation:
[Unicode 11.0]
The Unicode Consortium. The Unicode Standard, Version 11.0.0, (Mountain View, CA: The Unicode Consortium, 2018. ISBN 978-1-936213-19-1)

For references consulted particularly in designing the repertoire for the Khmer script for the Root Zone please see details in the Table of References below. Reference [3] refers to the Unicode Standard version in which the corresponding code points were initially encoded. References [100], [203], [204], [205], [206], [207], [208], [209] & [210] correspond to sources justifying the inclusion of or classification for the corresponding code points. Entries in the table may have multiple source reference values.


Repertoire Summary

Number of elements in repertoire 73
Number of code points 71
Number of sequences 2
Longest code point sequence 2

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.

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.

Glyph Script Name Ref Tags Required Context Variants Comment
U+1780 Khmer KHMER LETTER KA [3], [203], [205] consonant, series-three     Khmer
U+1781 Khmer KHMER LETTER KHA [3], [203] consonant     Khmer
U+1782 Khmer KHMER LETTER KO [3], [203] consonant     Khmer
U+1783 Khmer KHMER LETTER KHO [3], [203] consonant     Khmer
U+1784 Khmer KHMER LETTER NGO [3], [203], [205], [210] consonant, series-three, series-two     Khmer
U+1785 Khmer KHMER LETTER CA [3], [203], [205] consonant, series-three     Khmer
U+1786 Khmer KHMER LETTER CHA [3], [203] consonant     Khmer
U+1787 Khmer KHMER LETTER CO [3], [203] consonant     Khmer
U+1788 Khmer KHMER LETTER CHO [3], [203] consonant     Khmer
U+1789 Khmer KHMER LETTER NYO [3], [203], [205], [210] consonant, series-three, series-two     Khmer
U+178A Khmer KHMER LETTER DA [3], [203] consonant     Khmer
U+178B Khmer KHMER LETTER TTHA [3], [203] consonant     Khmer
U+178C Khmer KHMER LETTER DO [3], [203] consonant     Khmer
U+178D Khmer KHMER LETTER TTHO [3], [203] consonant     Khmer
U+178E Khmer KHMER LETTER NNO [3], [203] consonant     Khmer
U+178F Khmer KHMER LETTER TA [3], [203], [205] consonant, series-three     Khmer
U+1790 Khmer KHMER LETTER THA [3], [203] consonant     Khmer
U+1791 Khmer KHMER LETTER TO [3], [203] consonant     Khmer
U+1792 Khmer KHMER LETTER THO [3], [203] consonant     Khmer
U+1793 Khmer KHMER LETTER NO [3], [203], [205] consonant, series-three     Khmer
U+1794 Khmer KHMER LETTER BA [3], [203], [205], [210] consonant, series-one, series-three, series-two     Khmer
U+1795 Khmer KHMER LETTER PHA [3], [203] consonant     Khmer
U+1796 Khmer KHMER LETTER PO [3], [203] consonant     Khmer
U+1797 Khmer KHMER LETTER PHO [3], [203] consonant     Khmer
U+1798 Khmer KHMER LETTER MO [3], [203], [210] consonant, series-two     Khmer
U+1799 Khmer KHMER LETTER YO [3], [203], [210] consonant, series-two     Khmer
U+179A Khmer KHMER LETTER RO [3], [203], [210] consonant, series-two     Khmer
U+179B Khmer KHMER LETTER LO [3], [203], [205] consonant, series-three     Khmer
U+179C Khmer KHMER LETTER VO [3], [203], [210] consonant, series-two     Khmer
U+179F Khmer KHMER LETTER SA [3], [203], [205], [210] consonant, series-one, series-three     Khmer
U+17A0 Khmer KHMER LETTER HA [3], [203], [210] consonant, series-one     Khmer
U+17A1 Khmer KHMER LETTER LA [3], [203] base-only, consonant     Khmer
U+17A2 Khmer KHMER LETTER QA [3], [203], [210] consonant, series-one     Khmer
U+17A5 Khmer KHMER INDEPENDENT VOWEL QI [3], [206] independent-vowel     Khmer
U+17A6 Khmer KHMER INDEPENDENT VOWEL QII [3], [206] independent-vowel     Khmer
U+17A7 Khmer KHMER INDEPENDENT VOWEL QU [3], [206] independent-vowel     Khmer
U+17AA Khmer KHMER INDEPENDENT VOWEL QUUV [3], [206] independent-vowel     Khmer
U+17AB Khmer KHMER INDEPENDENT VOWEL RY [3], [206] independent-vowel     Khmer
U+17AC Khmer KHMER INDEPENDENT VOWEL RYY [3], [206] independent-vowel     Khmer
U+17AD Khmer KHMER INDEPENDENT VOWEL LY [3], [206] independent-vowel     Khmer
U+17AE Khmer KHMER INDEPENDENT VOWEL LYY [3], [206] independent-vowel     Khmer
U+17AF Khmer KHMER INDEPENDENT VOWEL QE [3], [206] independent-vowel     Khmer
U+17B0 Khmer KHMER INDEPENDENT VOWEL QAI [3], [206] independent-vowel     Khmer
U+17B1 Khmer KHMER INDEPENDENT VOWEL QOO TYPE ONE [3], [206] independent-vowel     Khmer
U+17B3 Khmer KHMER INDEPENDENT VOWEL QAU [3], [206] independent-vowel     Khmer
U+17B6  ា Khmer KHMER VOWEL SIGN AA [3], [204] dependent-vowel, dependent-vowel-1 follows-consonant-robat-shifter   Khmer
U+17B7  ិ Khmer KHMER VOWEL SIGN I [3], [204] dependent-vowel, dependent-vowel-2, dependent-vowel-3 follows-consonant-robat-shifter   Khmer
U+17B8  ី Khmer KHMER VOWEL SIGN II [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17B9  ឹ Khmer KHMER VOWEL SIGN Y [3], [204] dependent-vowel, dependent-vowel-2 follows-consonant-robat-shifter   Khmer
U+17BA  ឺ Khmer KHMER VOWEL SIGN YY [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17BB  ុ Khmer KHMER VOWEL SIGN U [3], [204] dependent-vowel, dependent-vowel-1, dependent-vowel-2 follows-consonant-robat-shifter   Khmer
U+17BC  ូ Khmer KHMER VOWEL SIGN UU [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17BD  ួ Khmer KHMER VOWEL SIGN UA [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17BE  ើ Khmer KHMER VOWEL SIGN OE [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17BF  ឿ Khmer KHMER VOWEL SIGN YA [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17C0  ៀ Khmer KHMER VOWEL SIGN IE [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17C1  េ Khmer KHMER VOWEL SIGN E [3], [204] dependent-vowel, dependent-vowel-2 follows-consonant-robat-shifter   Khmer
U+17C2  ែ Khmer KHMER VOWEL SIGN AE [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17C3  ៃ Khmer KHMER VOWEL SIGN AI [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17C4  ោ Khmer KHMER VOWEL SIGN OO [3], [204] dependent-vowel, dependent-vowel-2 follows-consonant-robat-shifter   Khmer
U+17C5  ៅ Khmer KHMER VOWEL SIGN AU [3], [204] dependent-vowel follows-consonant-robat-shifter   Khmer
U+17C6  ំ Khmer KHMER SIGN NIKAHIT [3], [204] sign follows-consonant-depvowel-1-shifter   Khmer
U+17C7  ះ Khmer KHMER SIGN REAHMUK [3], [208] sign follows-consonant-depvowel-2-shifter   Khmer
U+17C8  ៈ Khmer KHMER SIGN YUUKALEAPINTU [3], [207], [208], [209] sign follows-consonant   Khmer
U+17C9  ៉ Khmer KHMER SIGN MUUSIKATOAN [3], [207], [208], [209], [210] shifter follows-series-two   Khmer
U+17CA  ៊ Khmer KHMER SIGN TRIISAP [3], [207], [208], [209], [210] shifter follows-series-one   Khmer
U+17CB  ់ Khmer KHMER SIGN BANTOC [3], [205], [207], [208], [209] sign follows-series-three   Khmer
U+17CC  ៌ Khmer KHMER SIGN ROBAT [3], [207], [208], [209] robat follows-consonant   Khmer
U+17CD  ៍ Khmer KHMER SIGN TOANDAKHIAT [3], [207], [208], [209] sign follows-consonant-or-vowel-i   Khmer
U+17D0  ័ Khmer KHMER SIGN SAMYOK SANNYA [3], [207], [208], [209] sign follows-consonant-shifter   Khmer
U+17D2  ្ Khmer KHMER SIGN COENG [3], [100] coeng coeng-context   Khmer
U+17D2 U+178A  ្ដ {Khmer} KHMER CONSONANT SIGN COENG DA [3] [coeng] + [consonant] follows-consonant set 1 Khmer
U+17D2 U+178F  ្ត {Khmer} KHMER CONSONANT SIGN COENG TA [3] [coeng] + [consonant, series-three] follows-consonant set 1 Khmer


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.
The shape displayed depends on the fonts available to your browser.
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.
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 “+”.
Links to the references associated with the code point or sequence, if any.
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.
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.
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.

Variant Sets

Variant Set Summary

Number of variant sets 1
Largest variant set 2
Variants by Type
blocked 2

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

By convention, the smaller of the two code points in a variant mapping pair.
By convention, the larger of the two code points in a variant mapping pair.
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.
The type of the variant mapping, including predefined variant types such as “allocatable” and “blocked”; or any that are defined specifically for this LGR.
One or more reference IDs (optional). A “/” separates references for reverse / forward mappings, if different.
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
17D2 178A  ្ដ 17D2 178F  ្ត blocked   Khmer subscript form homoglyph

Classes, Rules and Actions

Character Classes

Number of named classes 10
Implicit (except script) 5
Implict defined by script tag 1

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
consonant Tag=consonant 33 {1780-179C 179F-17A2}   Any Khmer consonant
consonant-but-not-base-only combined =
[[:consonant:] ∖ [:base-only:]]
32 {1780-179C 179F-17A0 17A2}   Any Khmer consonant that is not base-only
dependent-vowel-1 Tag=dependent-vowel-1 2 {17B6 17BB}   Dependent Khmer vowels used with NIKAHIT
dependent-vowel-2 Tag=dependent-vowel-2 5 {17B7 17B9 17BB 17C1 17C4}   Dependent Khmer vowels used with REAHMUK
dependent-vowel-3 Tag=dependent-vowel-3 1 {17B7}   Dependent Khmer vowel used with TOANDAKHIAT
robat Tag=robat 1 {17CC}   Khmer ROBAT
series-one Tag=series-one 4 {1794 179F-17A0 17A2}   Khmer consonants used with MUUSIKATOAN
series-three Tag=series-three 9 {1780 1784-1785 1789 178F 1793-1794 179B 179F}   Khmer consonants used with BANTOC
series-two Tag=series-two 7 {1784 1789 1794 1798-179A 179C}   Khmer consonants used with TRIISAP
shifter Tag=shifter 2 {17C9-17CA}   Any Khmer shifter (MUUSIKATOAN or TRIISAP)
implicit Tag=base-only 1 {17A1}   The character tagged as base-only
implicit Tag=coeng 1 {17D2}   The character tagged as coeng
implicit Tag=dependent-vowel 16 {17B6-17C5}   Any character tagged as dependent-vowel
implicit Tag=independent-vowel 12 {17A5-17A7 17AA-17B1 17B3}   Any character tagged as independent-vowel
implicit Tag=sign 6 {17C6-17C8 17CB 17CD 17D0}   Any character tagged as sign
implicit Tag=sc:Khmr 71 {1780-179C 179F-17A2 17A5-17A7 17AA-17B1 17B3 17B6-17CD 17D0 17D2}   Any character tagged as Khmer


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 "...".
A named or implicit class defined by all code points that share the given tag value (ttt).
An anonymous class implicitly defined based on tag value and for which there is no named equivalent.
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 ( = union, = intersection, = difference, = symmetric difference).

Whole label evaluation and context rules

Number of rules 13
Used to trigger actions 2
Used as context rule (C) 10
Anchored context rules 10
Used only in another rule 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
Anchor Used as
Ref Comment
leading-combining-mark (start)[[\p{gc=Mn}] ∪ [\p{gc=Mc}]]       Default WLE rule matching labels with leading combining marks ⍟
subscript-consonant \u17D2[:consonant-but-not-base-only:]         WLE Rule 2: allowable subscript consonant sequence
subscript-consonant-limit (:subscript-consonant:){3,3}       WLE Rule 3: more than two subscript consonants
coeng-context ([:consonant:])← ⚓︎ →([:consonant-but-not-base-only:])   C   WLE Rule 4: checks for 17D2 and its surrounding code points
follows-consonant-robat-shifter ([:shifter:]|[:consonant:]|[:robat:])← ⚓︎   C   WLE Rule 5: makes sure that dependent vowel follows a consonant or a shifter or a robat
follows-series-two ([:series-two:])← ⚓︎   C   WLE Rule 6: checks sequence for shifter 17C9 MUUSIKATOAN
follows-series-one ([:series-one:])← ⚓︎   C   WLE Rule 7: checks sequence for shifter 17CA TRIISAP
follows-consonant ([:consonant:])← ⚓︎   C   WLE Rule 8: checks if sign code point or subscript consonant follows a consonant
follows-consonant-shifter ([:consonant:]|[:shifter:])← ⚓︎   C   WLE Rule 9: checks if 17D0 KHMER SIGN SAMYOKSANNYA follows a consonant or a shifter
follows-consonant-depvowel-1-shifter ([:consonant:]|[:dependent-vowel-1:]|[:shifter:])← ⚓︎   C   WLE Rule 10: checks if 17C6 KHMER SIGN NIKAHIT follows a consonant or a dependent vowel-1 or a shifter
follows-consonant-depvowel-2-shifter ([:consonant:]|[:dependent-vowel-2:]|[:shifter:])← ⚓︎   C   WLE Rule 11: checks if 17C7 KHMER SIGN REAHMUK follows a consonant or a dependent vowel-2 or a shifter
follows-series-three ([:series-three:])← ⚓︎   C   WLE Rule 12: checks if 17CB KHMER SIGN BANTOC code point follows a series-three consonant
follows-consonant-or-vowel-i ([:consonant:][:dependent-vowel-3:]?)← ⚓︎   C   WLE Rule 13: checks if 17CD KHMER SIGN TOANDAKHIAT follows a consonant or 17B7 KHMER VOWEL SIGN I (Dependent-vowel-3)


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.
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.
(: :) - rule reference
Non-recursive reference to a named rule.
(... | ...) - 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.
*, +, ?, {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 ( = union, = intersection, = difference, = symmetric difference).
⍟ - default rule
Rules marked with ⍟ are included by default and may or may not be triggered by any possible label under this LGR.


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   labels with leading combining marks are invalid ⍟
2 if at least one variant is in {out-of-repertoire-var} invalid   any variant label with a code point out of repertoire is invalid ⍟
3 if label matches subscript-consonant-limit invalid   any label with more than two subscript consonants in a row 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) ⍟


{...} - 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.

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.

[3] The Unicode Standard 3.1
Any code point originally encoded in Unicode 3.0
[100] The Unicode Consortium. The Unicode Standard, Version 8.0.0, (Mountain View, CA: The Unicode Consortium, 2015. ISBN 978-1-936213-10-8), Chapter 16: Southeast Asia, Section 16.4: Khmer,
Subsection, Subscript Consonant Signs, pages 616-618
[203] PRIMARY SCHOOL GRADE 1, MOEYS, ISBN 9-789-995-001-674, Publication 2015, Figure 1
Any code point cited is for consonant characters
[204] PRIMARY SCHOOL GRADE 1, MOEYS, ISBN 9-789-995-001-674, Publication 2015, Figure 2
Any code point cited is for vowel signs
[205] Dr. Prum Mol (Khmer Linguist), Grammar of Modern Khmer Language, Linguist of National Institute of Language, Royal Academy of Cambodia, 2006, page 37 Bantoc sign section starts towards the bottom of the page, page 38 list the context of the Bantoc sign
BANTOC sign and its context
[206] PRIMARY SCHOOL GRADE 1, MOEYS, ISBN 9-789-995-001-674, Publication 2015, Figure 6
Any code point cited is for independent vowel characters
[207] PRIMARY SCHOOL GRADE 1, MOEYS, ISBN 9-789-995-001-674, Publication 2015, Figure 7
Any code point cited is for diacritics
[208] PRIMARY SCHOOL GRADE 1, MOEYS, ISBN 9-789-995-001-674, Publication 2015, Figure 8
Any code point cited is for diacritics
[209] PRIMARY SCHOOL GRADE 1, MOEYS, ISBN 9-789-995-001-674, Publication 2015, Figure 9
Any code point cited is for diacritics
[210] Franklin E. Huffman, Cambodian System of Writing and Beginning Reader, Yale University, 1970, reprinted 1987
Sets of code points used with certain signs