Overview

For more details on this proposal see "Proposal for a Khmer Script Root Zone LGR [Proposal]"

Repertoire

According to Section 5 "Repertoire", in "[Proposal]".

Variants

According to Section 6 "Variants", in "[Proposal]", two Khmer consonants are 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.

Character Classes

Some consonants have been given the tag "base only"; these do not take subscript form.

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 series, and the sets of code points used with these two signs are defined in [210]. The character U+17CB (់) KHMER SIGN BANTOC is used with a subset of consonants, that subset has been given the tag "series-three" [205]. The characters U+17C9 (៉) KHMER SIGN MUUSIKATOAN and U+17CA (៊) KHMER SIGN TRIISAP are collectively known as consonant shifters and have been given the tag "shifter".

The character U+17CC (៌) KHMER SIGN ROBAT has been given the tag "robat".

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 Section 5.3 in [Proposal]). 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 Section 5.3 in [Proposal]). The code point U+17B7 (ិ) KHMER VOWEL SIGN I has been given a tag "dependent-vowel-3".

Whole Label Evaluation (WLE) and Context Rules

Default Whole Label Evaluation Rules

The LGR includes the set of required default WLE rules and actions applicable to the Root Zone and defined in [MSR-2]. 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

Rules provided in the LGR as described in Section 7 of [Proposal] reasonably restrict labels so that they conform to Khmer syllable structure. Where possible these constraints are presented as context rules.

The rules are:

• Subscript-consonant A rule that specifies allowable consonant sequence. See Section 7.2 in [Proposal]
• Subscript-consonant-limit It limits the occurrence of subscript-consonant to two. In case of three, label is stated as invalid. See Section 7.3 in [Proposal]
• Coeng-context A context rule for 17D2 that must have a consonant or base-only before it and a consonant after it. See Section 7.4 in [Proposal]
• Follows-consonant-robat-shifter A context rule for those code points that must follow a consonant, robat or shifter. See Section 7.5 in [Proposal]
• Follows-series-two A context rule for those code points that must follow series-two consonants. See Section 7.6 in [Proposal]
• Follows-series-one A context rule for those code points that must follow series-one consonants. See Section 7.7 in [Proposal]
• Follows-consonant A context rule for those code points that must always follow a consonant. See Section 7.8 in [Proposal]
• Follows-consonant-shifter A context rule for those code points that must always follow a consonant or shifter. See Section 7.9 in [Proposal]
• Follows-consonant-depvowel-1-shifter A context rule for those code points that must follow consonant, shifter or dependent-vowel-1. See Section 7.10 in [Proposal]
• Follows-consonant-depvowel-2-shifter A context rule for those code points that must follow consonant, shifter or dependent-vowel-2. See Section 7.11 in [Proposal]
• Follows-series-three A context rule for those code points that must follow series-three consonants. See Section 7.12 in [Proposal]
• Follows-consonant-or-vowel-i A context rule for those code points that must follow a consonant or 17B7 KHMER VOWEL SIGN I. See Section 7.13 in [Proposal]

References

Reference value ("ref" attribute) 3 refers to Unicode Standard versions in which corresponding code points were initially encoded. Reference values 203, 204, 205, 206, 207, 208, 209 & 210 correspond to sources justifying the inclusion of or classification for the corresponding code points. Single code point or ranges may have multiple source reference values.

Reference values ("ref" attribute") from 101 and up refer to specific sources cited for the corresponding code points in the "[Proposal]".

In addition the following references are cited in this document:

[MSR-2]

Integration Panel, "Maximal Starting Repertoire — MSR-2 Overview and Rationale", 14 April 2015 https://www.icann.org/en/system/files/files/msr-2-overview-14apr15-en.pdf

[Proposal]

Proposal for Khmer Script Root Zone LGR, https://www.icann.org/resources/pages/lgr-proposals-2015-12-01-en

[Unicode6.3]

The Unicode Consortium. The Unicode Standard, Version 6.3.0, (Mountain View, CA: The Unicode Consortium, 2013. ISBN 978-1-936213-08-5) http://www.unicode.org/versions/Unicode6.3.0/

For more details for references [100] and up and [3] and up refer to the Table of References below.