MON NGA

[Richard Wordingham]

I'm having trouble with the character identity of U+105A MYANMAR LETTER
MON NGA, in particular when followed by U+103A MYANMAR SIGN ASAT.  Is
there any guide to when it should be encoded differently to U+1004
MYANMAR LETTER NGA?  Are there any rules on when the tail below is
mandatory, optional or prohibited?

Where shaping is at work, the Unicode charts do not attempt to help one
to identify characters; rather they assume that the Platonic identifies
of the characters is obvious.  Unsurprisingly, this helpful assumption
is sometimes false.

Current practice on the Mon Wikipedia includes the rule that Mon text
should have <1004, 103A> rather than <105A, 103A> so that the tail of
MON NGA will not appear.  The Thai Mon text in L2/20-163 also appears to
have the rule that ASAT suppresses the tail.  Is this rule of the Mon
Wikipedia simply fighting a bad font, or does Mon text naturally mix
U+1004 and U+105A?

Richard.