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Add parser example

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Chris Done 2019-11-25 14:33:31 +00:00
parent 19e0e51d9d
commit 3d0ec5488a
1 changed files with 16 additions and 0 deletions
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examples/parser.hs Normal file
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data Result a = OK a String | Error String
data Parser a = Parser (String -> Result a)
parseBool =
Parser
(\string ->
case take 4 string of
"True" -> OK True (drop 4 string)
_ ->
case take 5 string of
"False" -> OK False (drop 5 string)
_ -> Error (append "Expected a bool, but got: " string))
runParser =
\p s ->
case p of
Parser f -> f s
main = runParser parseBool "TrueFalse"