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Discussion on: Elm challenge on Exercism: Rna Transcription

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stevensonmt profile image
stevensonmt

Consider rewriting those conditionals as a case statement. Then make the return of the case statement a Result type.

case x of
    'G' -> Just 'C'
    'C' -> Just 'G'
    'T' -> Just 'A'
    'A' -> Just 'U'
    _ -> Err "There is an Unknown Character in the DNA sequence!!!"

Now all arms are the same type and the compiler won't complain.

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antonrich profile image
Anton Author

I wanted to use case, but then I wondered if elm has if else expression. So I didn't get to the case.

Thanks for pointing out to the Result type. I didn't know that exists.

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stevensonmt profile image
stevensonmt

I believe case statements are considered more idiomatic in elm.