37 lines
748 B
Markdown
37 lines
748 B
Markdown
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---
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title: bidirectional
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github: https://github.com/MasseR/bidirectional
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issues: https://github.com/MasseR/bidirectional/issues
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---
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Bidirectional serialization based on Lysxia's post on [Monadic profunctors for bidirectional programming](https://blog.poisson.chat/posts/2017-01-01-monadic-profunctors.html).
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Let's assume we have a parser like the following
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``` haskell
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int :: Parser (ReaderT String Maybe) (Writer [Int]) Int Int
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int = parser (ReaderT readMaybe) (\x -> x <$ tell [show x])
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```
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Then you can use the parser for parsing:
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```
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> runReaderT (decode int) "3"
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Just 3
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```
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Or for encoding:
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```
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> execWriter (encode int 3)
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["3"]
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```
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Or combine both of them
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```
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> runReaderT (decode int) $ head $ execWriter $ encode int 3
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Just 3
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```
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