This file contains Label Generation Rules (LGR) for the Lao script for the Root zone. For more details on this LGR and its development, see "Proposal for a Lao Script Root Zone LGR [Proposal]". The format of this file follows [RFC 7940].
In addition to the 51 code points according to Section 5 “Repertoire” in [Proposal], the sequence 0EB2 0EB0 has been defined to facilitate implementation of WLE rule follows-vafter-context as a context rule. The repertoire only includes code points used by languages that are actively written in the Khmer script. The repertoire is based on [MSR-4], which is a subset of [Unicode 6.3].
Each code point or range is tagged with the script or scripts that the code point is used with, and one or more references documenting sufficient justification for inclusion in the repertoire, see "References" below.
According to Section 6, "Variants" in [Proposal], this LGR defines no variants.
Some consonants have been given the tag of Cf, which indicates final consonants. Other character classes that have been used are semi-consonant, tone-mark, vowel-above, vowel-before, vowel-below and vowel-after. See Section 5 of the [Proposal].
The LGR includes the set of required default WLE rules and actions applicable to the Root Zone and defined in [MSR-4]. They are marked with ⍟. The default prohibition on leading combining marks is equivalent to ensuring that a label only starts with a consonant or vowel-before.
Rules provided in the LGR as described in Section 7 of [Proposal] reasonably restrict labels so that they conform to Lao syllable structure. These constraints are presented exclusively as context rules.
The rules are:
No context rules apply to “consonant” code points. For discussion, see Section 5.1 “Consonants” in [Proposal].
For methodology and contributors, see Sections 4 and 8 of [Proposal].
The following general references are cited in this document:
For references consulted particularly in designing the repertoire for the Lao script for the Root Zone please see details in the Table of References below. Reference [0] refers to Unicode Standard version in which corresponding code points were initially encoded. References [201], [202], [203], [204], 205], [206], & [207] correspond to sources justifying the inclusion of or classification for the corresponding code points. Single code points or ranges may have multiple source reference values.
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