40 lines
1.1 KiB
Haskell
40 lines
1.1 KiB
Haskell
-- | Calculate the width of String and Text, being aware of wide characters.
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module Text.WideString (
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-- * Text Builders which keep track of length
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WideBuilder(..),
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wbUnpack,
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wbToText,
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wbFromText
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) where
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import Data.Text (Text)
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import qualified Data.Text.Lazy as TL
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import qualified Data.Text.Lazy.Builder as TB
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import Text.DocLayout (realLength)
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-- | Helper for constructing Builders while keeping track of text width.
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data WideBuilder = WideBuilder
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{ wbBuilder :: !TB.Builder
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, wbWidth :: !Int
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} deriving (Show)
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instance Semigroup WideBuilder where
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WideBuilder x i <> WideBuilder y j = WideBuilder (x <> y) (i + j)
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instance Monoid WideBuilder where
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mempty = WideBuilder mempty 0
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-- | Convert a WideBuilder to a strict Text.
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wbToText :: WideBuilder -> Text
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wbToText = TL.toStrict . TB.toLazyText . wbBuilder
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-- | Convert a strict Text to a WideBuilder.
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wbFromText :: Text -> WideBuilder
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wbFromText t = WideBuilder (TB.fromText t) (realLength t)
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-- | Convert a WideBuilder to a String.
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wbUnpack :: WideBuilder -> String
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wbUnpack = TL.unpack . TB.toLazyText . wbBuilder
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