Convert Unicode value to Char in Haskell

Question

I'm writing a JSON parser in Haskell but I'm having trouble parsing unicode values. If I want to convert \u2013 to a character, I can just wrap it in quotes in Python and I get '–'. I'm having trouble figuring out how to do the same in Haskell. If I wrap it in quotes, I get the error "lexical error in string/character literal at character 'u'" If I run putStrLn "\2013", I get the character 'ߝ'. How can I get the '–' character in Haskell?

Note, it's a coincidence that both JSON and Python use the same syntax for writing arbitrary Unicode characters in ASCII. — chepner
– chepner, Commented Oct 14, 2022 at 19:39
"Wrapping in quotes" is a Haskell compile time feature that you wouldn't try to use to parse strings at runtime. You would instead parse \u2013 to extract the integer value 8211 and use Data.Char.chr :: Int -> Char on it. — that other guy
– that other guy, Commented Oct 14, 2022 at 19:43

Daniel Wagner · Accepted Answer · 2022-10-14 19:36:44Z

5

Plain digits is base 10; for base 16, use the x prefix.

> putStrLn "\x2013" –

BUT you shouldn't need to know this. Use aeson for your JSON parsing needs.

answered Oct 14, 2022 at 19:36

Daniel Wagner

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noatbfgtxa Over a year ago

Thank you, this worked. I'm trying to make a JSON parser mostly as a learning exercise but thanks for the recommendation.

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