Creates a completer that reads the current input table on demand.
Callback that returns the active input table.
Looks up candidates for a composing prefix.
If the prefix begins with an uppercase letter, both the original prefix and its lowercased form are searched so the returned display text can preserve initial capitalization.
The composing prefix to search for.
Matching candidates sorted by display-text length.
Performs prefix lookup against the current input table.
The completer reads the active table on demand, finds matching rows by prefix, merges duplicate surface forms, and returns candidates sorted by display-text length.