First steps towards a thing that will generate a randomized zine

recombiner1.hs

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+import System.IO
+import System.Random
+
+-- we're starting with a file where sections are separated by
+-- begin-section
+-- end-section
+
+collectSections :: [String] -> [String]
+collectSections strs = collectSections' strs []
+
+-- if we don't close an accumulation we just throw it away
+-- we also don't check for beginning a new section inside a section
+collectSections' [] accum = []
+collectSections' (x:xs) accum | x == "begin-section" = collectSections' xs []
+                              | x == "end-section" = (unlines $ reverse accum) : collectSections' xs []
+                              | otherwise = collectSections' xs (x : accum)
+
+parseFile :: String -> [String]
+parseFile = collectSections . lines
+
+-- this function shouldn't just split the lists at the point
+-- but grab the element at that point
+-- [0,1,2,4]
+-- this function is only defined for 1
+splitAtElem n xs = let (xl,xr) = splitAt n xs in (xl, head xr, tail xr)
+
+randomizeSections :: (RandomGen g) => g -> [String] -> [String]
+randomizeSections g [] = []
+randomizeSections g [x] = [x] 
+randomizeSections g xs = let (n,g') = uniformR (0,length xs-1) g -- 
+                             (l,x,r) = splitAtElem n xs
+                         in x : randomizeSections g' (l ++ r)
+  
+
+-- small testing main function, to replace
+main :: IO ()
+main = do
+  contents <- readFile "test.txt"
+  g <- initStdGen
+  let parsed = parseFile contents
+  putStrLn "Initial"
+  putStrLn $ unlines $ parsed
+  putStrLn "Randomized"
+  putStrLn $ unlines $ randomizeSections g $ parsed

test.txt

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+begin-section
+Here's some text that should be an independent unit
+end-section
+
+begin-section
+This is some more text.
+
+We want to make sure it all shows up with proper linebreaks and
+
+everything
+end-section
+
+
+this text should get completely ignored
+
+begin-section
+Hi there
+end-section
+
+
+