I'm very new in Haskell and I want to know how I can replace a predetermined word in a String by another word. This is my code so far, I know I can't do this for now:
treat :: String -> String
treat text = text
main::IO()
main = do argv <- getArgs
texte <- readFile "intputText"
print (separation text)
print ( treat text )
separation :: String -> [String]
separation [] = [""]
separation (c:cs) | c == "\Graph" = "Graphic : " : rest
| c == '}' = "" : rest
| c == '{' = "" : rest
| otherwise = (c : head rest) : tail rest
where rest = separation cs
So basically I know I can't put a String in the first c == "\Graph" so I want to know how I can basically replace every word "\Graph" in my String text by "Graphic".
I want to be able to do that without importing any package.
If anyone can help me out I'd really appreciate it.
Thank you very much!
replace :: String -> String -> String-> String
replace [] token repl = []
replace str@(s:ss) token@(t:tx) repl
-- check if first char of string equal to first char of token
| s == t = case validateToken token str of
Just list -> repl ++ replace list token repl
Nothing -> s : replace ss token repl
-- if not equal then continue recursion step
| otherwise = s: replace ss token repl
where
-- validate if token matches the following chars of the string
-- returns Nothing if token is not matched
-- returns the remaining string after the token if token is matched
validateToken:: String -> String -> Maybe String
validateToken (a:as) [] = Nothing
validateToken [] list = Just list
validateToken (a:as) (x:xs)
| a == x = validateToken as xs
| otherwise = Nothing
example = replace "yourString" "token" "new"