cto-af / linebreak Goto Github PK

The test on line 10287 of LineBreakTest.txt doesn't make sense to me:

× 1B18 ÷ 1B27 × 1B44 × 200C × 1B2B × 1B38 ÷ 1B31 × 1B44 × 1B1D × 1B36 ÷ # × [0.3] BALINESE LETTER CA (AK) ÷ [999.0] BALINESE LETTER PA (AK) × [28.12] BALINESE ADEG ADEG (VI) × [9.0] ZERO WIDTH NON-JOINER (CM1_CM) × [28.13] BALINESE LETTER MA (AK) × [9.0] BALINESE VOWEL SIGN SUKU (CM1_CM) ÷ [999.0] BALINESE LETTER SA SAPA (AK) × [28.12] BALINESE ADEG ADEG (VI) × [28.13] BALINESE LETTER TA LATIK (AK) × [9.0] BALINESE VOWEL SIGN ULU (CM1_CM) ÷ [0.3]

In particular, AK × VI × ZWJ × AK is supposed to match 28.13, which is:

28.13) ($AK | $DottedCircle | $AS) $VI × ($AK | $DottedCircle)

The ZWJ gets turned into VI by rule LB9. Therefore, when rule 28.13 runs, it sees AK VI VI AK, which doesn't match.

Note that LB9 says:

Do not break a combining character sequence; treat it as if it has the line breaking class of the base character in all of the following rules. Treat ZWJ as if it were CM.

LB9 does NOT say "treat it as if it is coalesced into the base character".