Provide more building blocks and extend example

byg/src/ComputationM.hs

@@ -2,6 +2,8 @@
 module ComputationM
   ( ComputationM
   , Token
+  , tupleTokens
+  , zipTokens
   , evalComputationM
   , inject
   , mapComputationM
@@ -30,10 +32,17 @@ deriving instance (Show a, Show b) => Show (TypedRun a b)
 data Token a where
   Token :: Int -> Token a
   TupleToken :: Token a -> Token b -> Token (a, b)
+  ZipToken :: Token [a] -> Token [b] -> Token [(a, b)]
   NoToken :: Token ()
 
 deriving instance Show (Token a)
 
+tupleTokens :: (Show a, Show b) => Token a -> Token b -> Token (a, b)
+tupleTokens = TupleToken
+
+zipTokens :: (Show a, Show b) => Token [a] -> Token [b] -> Token [(a, b)]
+zipTokens = ZipToken
+
 data Dependency a b = Dependency (Token a) (TypedRun a b) (Token b)
   deriving (Show)
 

byg/src/Functions.hs

@@ -3,7 +3,6 @@ module Functions
   ( isImageFilename
   , convertedImageFilename
   , listDirectory
-  , openImage
   , convertImage
   , saveFile
   , runPandoc
@@ -17,7 +16,6 @@ isImageFilename = runFunction IsImageFilename
 convertedImageFilename = runFunction ConvertedImageFilename
 
 listDirectory = runFunctionIO ListDirectory
-openImage = runFunctionIO OpenImage
 convertImage = runFunctionIO ConvertImage
 saveFile = runFunctionIO SaveFile
 runPandoc = runFunctionIO RunPandoc

byg/src/Main.hs

@@ -1,5 +1,6 @@
 module Main where
 
+import Types
 import ComputationM
 import Functions
 
@@ -7,16 +8,16 @@ handleRecipeDir :: Token FilePath -> ComputationM ()
 handleRecipeDir dir = do
   dirContents <- listDirectory dir
   imageFilenames <- filterComputationM isImageFilename dirContents
-  t <- inject ("hej", "hey.txt")
-  saveFile t
+  convertedImageFilenames <- mapComputationM convertedImageFilename imageFilenames
+  flip mapComputationM_ (zipTokens imageFilenames convertedImageFilenames) $ \files -> do
+    settings <- inject $ ResizeToWidth 800
+    convertImage $ tupleTokens files settings
 
 test :: ComputationM ()
 test = do
   dir <- inject "retter"
   dirContents <- listDirectory dir
   mapComputationM_ handleRecipeDir dirContents
-  t <- inject ("hej", "hey.txt")
-  saveFile t
 
 main :: IO ()
 main = mapM_ print $ evalComputationM test

byg/src/Sources.hs

@@ -1,3 +1,4 @@
+{-# OPTIONS_GHC -Wno-orphans #-}
 module Sources where
 
 -- TODO: Figure out if any of this is useful.
@@ -10,7 +11,7 @@ data Source a where
 instance SourceState FilePath where
   stateOfSource = undefined
 
-instance SourceState Image where
+instance SourceState ((FilePath, FilePath), ImageConversionSettings) where
   stateOfSource = undefined
 
 instance SourceState (String, FilePath) where

byg/src/Types.hs

@@ -3,7 +3,7 @@ module Types where
 
 import Data.ByteString (ByteString)
 
-data Image = Image
+data ImageConversionSettings = ResizeToWidth Int
   deriving (Show)
 
 class (SourceState a, Show f) => IsFunction f a b | f -> a b where