more string instructions

src/Instructions/StringInstructions.hs

@@ -2,6 +2,7 @@ module Instructions.StringInstructions where
 
 import State
 import Instructions.GenericInstructions
+import Data.List.Split
 
 combineString :: String -> (String, String) -> String
 combineString toInsert (front, back) = front <> toInsert <> back
@@ -15,3 +16,56 @@ instructionStringSwap state = instructionSwap state string
 instructionStringInsertString :: State -> State
 instructionStringInsertString state@(State{_string = s1 : s2 : ss, _int = i1 : is}) = state {_string = combineString s2 (splitAt i1 s1) : ss, _int = is}
 instructionStringInsertString state = state
+
+instructionStringFromFirstChar :: State -> State
+instructionStringFromFirstChar state@(State {_string = (schar : _) : ss}) = state {_string = [schar] : ss}
+instructionStringFromFirstChar state = state
+
+instructionStringFromLastChar :: State -> State
+instructionStringFromLastChar state@(State {_string = s1 : ss}) =
+  if not $ null s1
+    then state {_string = [last s1] : ss}
+    else state
+instructionStringFromLastChar state = state
+
+instructionStringFromNthChar :: State -> State
+instructionStringFromNthChar state@(State {_string = s1 : ss, _int = i1 : is}) =
+  let
+    index = abs i1 `mod` length s1
+  in
+    state{_string = [s1 !! index] : ss, _int = is}
+instructionStringFromNthChar state = state
+
+-- instructionStringContainsString :: State -> State
+-- instructionStringContainsString state@(State )
+
+-- Haskell is kinda really cool. This can totally be
+-- abstracted
+findSubString :: String -> String -> Int
+findSubString fullString subString 
+  | length fullString < length subString = -1
+  | length fullString == length subString = if fullString == subString then 0 else -1
+  | otherwise = findSubString' fullString subString 0
+  where
+    findSubString' :: String -> String -> Int -> Int
+    findSubString' fStr sStr index
+      | null fStr = -1
+      | length sStr > length fStr = -1
+      | sStr == take (length sStr) fStr = index
+      | otherwise = findSubString' (drop 1 fStr) sStr (index + 1)
+
+instructionStringIndexOfString :: State -> State
+instructionStringIndexOfString state@(State {_string = s1 : s2 : ss, _int = is}) = state {_string = ss, _int = findSubString s1 s2 : is}
+instructionStringIndexOfString state = state
+
+instructionStringContainsString :: State -> State
+instructionStringContainsString state@(State {_string = s1 : s2 : ss, _bool = bs}) = state {_string = ss, _bool = (findSubString s1 s2 /= -1) : bs}
+instructionStringContainsString state = state
+
+instructionStringSplitOnString :: State -> State
+instructionStringSplitOnString state@(State {_string = s1 : s2 : ss}) = state {_string = splitOn s2 s1 <> ss}
+instructionStringSplitOnString state = state
+
+instructionStringReplaceFirstString :: State -> State
+instructionStringReplaceFirstString state@(State {_string = s1 : s2 : s3 : ss}) = undefined -- TODO
+instructionStringReplaceFirstString state = state