Overview

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

Repertoire

The 51 code points are according to Section 5 “Repertoire” in [Proposal]. In addition, the sequence 0EB2 0EB0 has been defined to facilitate implementation of WLE rule follows-vafter-context as a context rule.

Variants

This LGR defines no variants.

Character Classes

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].

Whole Label Evaluation (WLE) 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 vowel-before.

Lao-specific Rules

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

The rules are:

• follows-consonant A context rule for semi-consonant. See Section 7 in [Proposal]. (WLE Rule No. 1)
• precedes-consonant A context rule for vowel-before. See Section 7 in [Proposal]. (WLE Rule No. 2)
• follows-main-consonant A context rule for vowel-below, and vowel-above. See Section 7 in [Proposal]. (WLE Rule No. 3)
• follows-C-tonemark-vabove A context rule for vowel-after. See Section 7 in [Proposal]. (WLE Rule No. 4)
• follows-vbefore-consonant-cluster A context rule for a vowel-after sequence. It incorporates consonant-cluster. See Section 7 in [Proposal]. (WLE Rule No. 5)
• follows-C-vabove-vbelow A context rule for tone mark. See Section 7 in [Proposal]. (WLE Rule No. 6)
• follows-Cf A context rule for LAO CANCELLATION MARK ໌ (U+0ECC) . See Section 7 in [Proposal]. (WLE Rule No. 7)
• repetition-mark-limit.. A rule that limits the occurrence of LAO KO LA ໆ (U+0EC6) at the label end. See Section 7 in [Proposal]. (WLE Rule No. 8)

No context rules apply to “consonant” code points. For discussion, see Section 5.1 “Consonants” in [Proposal].

References

Reference value ("ref" attribute) 0 refers to Unicode Standard versions in which corresponding code points were initially encoded. Reference values 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.

Reference values ("ref" attribute") from 201 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 Lao 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, refer to the Table of References below. Several of these references refer to a figure in an appendix of the [Proposal] document.