[Haskell-cafe] Automatically generate sum type members -> [String]

[David Kraeutmann]

readConstr [1] from Data.Data will do the trick. DataType for a type can
be retrieved with dataTypeOf.

----
1:
https://hackage.haskell.org/package/base-4.8.0.0/docs/Data-Data.html#v:readConstr

On 5/19/2015 1:20 AM, Cody Goodman wrote:
> Can I use either template Haskell, GHC Generics, or something else to
> get the list of Constructors in Codes? Then I could do `map show
> codeSumTypeMembers` and get `["A0100A","A0500A"]`?
> 
> Here's an example of solving this problem manually:
> 
> data Codes = A0100A | A0500A deriving Show
> 
> codeExists "A0100A" = True
> codeExists "A0500A" = True
> codeExists _ = False
> 
> 
> main = print $ codeExists xmlElementName
>        where xmlElementName = "A0500A"
> 
> -- λ> main
> -- True
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