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definition:
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class HasSpanInfo a => ExactPrint a where
keywords :: a -> [String]
printS :: a -> Exact
-- In some cases, the exact-printer has to account for additional spans
-- in order to exact-print the entity correctly. Usually, this is the case
-- for entities that have an explicit layout with additional spans that
-- are not covered by the entity's `SpanInfo` directly.
extraSpans :: a -> [Span]
extraSpans _ = []
-- Adds keywords to the whitespace-replacement of an EPS computation
-- and fills Whitespace up to the beginning
printN :: a -> PutExact
printN a = liftEPS $ withSrcInfoPoints spanInfo (keywords a) eps
where
EPSM (_, eps) = do
liftEPS $ fillUpS (getStartPosition a) -- fill space before entity
unExact $ printS a -- collect keywords to print
liftEPS $ fillUpS (getEndPosition spanInfo) -- print them, add trailing space
spanInfo = case extraSpans a of
[] -> getSpanInfo a
sps -> mergeSpanInfo (getSpanInfo a) sps
where
mergeSpanInfo spi sps2 = case spi of
(SpanInfo sp sps1) ->
let sps' = sortBy (\(Span p1 _) (Span p2 _) -> p1 < p2) (sps1 ++ sps2)
endPos = end (last sps')
in setEndPosition endPos $ SpanInfo sp sps'
_ -> error "mergeSpanInfo: No Span Info!"
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