Chillu-RA + C2 => eyelash-repha over C2, if available in the font.
We can use joiners – ZWJ & ZWNJ - in their usual meaning: respectively forcing or avoiding the conjunct formation.
As per Uniqueness Rule, RA + VIRAMA + C2 should not form eyelash repha conjunct.
This method has the advantage that reader gets the choice to view a word with eyelash-repha or explicit Chillu-RA. eg:
This method has the advantage that reader gets the choice to view a word with eyelash-repha or explicit Chillu-RA. eg:(with eyelash-repha) and (with explicit Chillu-RA). Both the words are valid, but different renderings of the same word.
Unfortunately, all the words with eyelash-repha are not like that. For example, the word (meaning 'subject matter') has no representation with explicit Chillu-RA. This can violate Uniqueness Rule because it is wrong to write without eyelash-repha. Instead, it should be correctly written as which is a different spelling.
To solve this issue, we may be forced to bring in a separate codepoint for Malayalam eyelash-repha. However, that would remove the reader's choice on viewing or not viewing eyelash-repha in words like .