[HarfBuzz] Contextual shaping of Malayalam post(pre)/below base forms
sureshp at gmx.com
Fri Jun 28 20:33:20 PDT 2013
Behdad Esfahbod wrote:
> On 13-06-18 06:46 PM, Richard Wordingham wrote:
>> lookup pref_st2
>> | y1 xx r3 | -- No sequence indices for this context!
>> | xx r3 |
> This wouldn't work. You should match y1 in backtrack sequence, not input
> sequence. Otherwise this is what happens, if you have a sequence y1 xx r3:
> - HB tries applying the lookup at position zero, matches the first rule, stops,
> - It then advances position by one, trying to apply the rule at position
> one, now the second rule matches and ligature is formed.
> For a rule to stop a later one from applying they should apply to the same
> input sequence at the same position, ie, both should have "xx r3" as their
> input, and the first one should have more context in terms of backtrack /
> lookahead... It can have a longer input sequence too, but they should start
> the same.
Thanks for the insightful explanation. I had non-contextual lookups too.
Removing them solved the issues.
>> 0 pref_lkp1
>> end lookup
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