What is U+0E46 THAI CHARACTER MAIYAMOK?

[Richard Wordingham via Unicode]

On Wed, 7 Feb 2018 22:02:28 -0800
Asmus Freytag via Unicode <unicode at unicode.org> wrote:

> On 2/7/2018 9:23 PM, Theppitak Karoonboonyanan via Unicode wrote:
> An apparent way to do it properly is to use NBSP before
> MAIYAMOK and a normal space after, and not to include
> any leading space in the glyph, but it seems inconvenent
> to input NBSP in common text editors.
> 
> Any text editor that has the ability to handle slightly more complex
> input scenarios could be programmed to convert SP to NBSP before
> MAIYAMOK.
> 
> A./
> 

For any compliant tailorable implementation of the Unicode line-breaking
algorithm, the correct method is for U+0E46 to be tailored to have
line_break=exclamation.  (U+0021 EXCLAMATION MARK is often offset
by a space in Thai.)  I know it works in ICU Version 53; I
haven't tested later versions.  Although NBSP is available in
Windows-874 and IANA-registered tis620 (as 0xA0), it is not available
in TIS-620, the national 8-bit standard.

What of a word break between a letter and MAIYAMOK in text tagged as
Thai? Should it be never, always or sometimes?  Should it depend on
whether there is an intermediate space?

Richard.