haskell - How to read exact N chars with Parsec? -
i'm new haskell , parsec. wish parse php-serialize format of string 's:numb:"string";'
s:12:"123";6789012";
where number count of chars. so, function looks like:
newtype phpstring = phpstring string pstring :: genparser char st phpstring pstring = { string "s:" ; value1 <- many1 digit ; string ":\"" ; value2 <- takeexactnchars (read value1) ; string "\";" ; return $ phpstring value2 } takeexactnchars n = ???????
i write using replicatem control.monad:
import text.parsercombinators.parsec import control.monad (replicatem) pstring :: parser string pstring = string "s:" n <- fmap read (many1 digit) string ":\"" -- bug fix; weren't picking colon s <- replicatem n anychar string "\";" return s testing in ghci:
*main> parse pstring "" "s:12:\"123\";6789012\";" right "123\";6789012" 
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