parse JSON input files (in Haskell)

README.md

@@ -6,27 +6,31 @@ The original idea behind this small project was to take the "computation graph"
 files generated by  [`circom-witnesscalc`](https://github.com/iden3/circom-witnesscalc),
 and either interprets or compiles them to various algebra backends.
 
-While this is quite straightforward in principle, and seems to work on small
+While this is quite straightforward in principle, and seems to work on particular
-examples, it turns out that `circom-witnesscalc` itself is completely broken,
+examples, it turns out that `circom-witnesscalc` itself has some serious limitations.
-in the sense that it doesn't seem to be able to handle nontrivial circuits using any 
-kind of meaningful metaprogramming (that being the only thing which makes `circom` 
-borderline useful).
 
-And this doesn't look fixable without something like a full rewrite of `circom-witnesscalc` (?).
+The biggest one is that it doesn't support any kind of dynamic computation (which should 
+be obvious from the fact that it produces a static graph). But even if one uses only 
+static computations, there are further very annoying things which just don't work.
+
+However at the end this is still a useful thing.
 
 ### Implementation status
 
 Compiler (in Haskell):
 
 - [x] parsing the graph file
+- [x] parsing json input
 - [x] naive interpreter
+- [ ] exporting the witness
 - [ ] constantine backend
 - [ ] zikkurat backend
 - [ ] arkworks backend
 
-Nim witness generator:
+Nim witness generator (to be used with [`nim-groth16`](https://github.com/codex-storage/nim-groth16))
 
 - [x] parsing the graph file
+- [ ] parsing json input
 - [ ] generating the witness
 - [ ] proper error handling
 

haskell/src/JSON.hs

@@ -0,0 +1,52 @@
+
+-- | Parse JSON input files
+
+module JSON where
+
+--------------------------------------------------------------------------------
+
+import Data.List
+import Data.Foldable           as F
+import Data.Foldable.WithIndex as FI
+
+import Data.Map (Map)
+import qualified Data.Map as Map 
+
+import qualified Data.Text       as T
+import qualified Data.ByteString as B
+
+import Data.Aeson
+import Data.Aeson.Key as Key
+import Data.Scientific
+
+--------------------------------------------------------------------------------
+
+parseInputJsonValue :: Value -> Map String [Integer]
+parseInputJsonValue val =
+  case val of 
+    Object obj -> Map.fromList (map worker (FI.itoList obj))
+    _ -> error "parseInputJsonValue: expecting a JSON object"
+  where
+
+    worker (key,value) = (Key.toString key, flatten value)
+
+    flatten :: Value -> [Integer]
+    flatten val = case val of
+      Number num -> numberToInteger num
+      Array  arr -> F.concatMap flatten arr  
+      String txt -> [read (T.unpack txt)]
+      _          -> error "parseInputJsonValue/flatten: expecting a number or an array"
+
+    numberToInteger x = case floatingOrInteger x of
+      Right y -> [y]
+      Left  _ -> error "parseInputJsonValue/numberToInteger: expecting an integer"
+
+--------------------------------------------------------------------------------
+
+loadInputJsonFile :: FilePath -> IO (Map String [Integer])
+loadInputJsonFile fpath = do
+  text <- B.readFile fpath
+  let Just value = decodeStrict text
+  return $ parseInputJsonValue value
+
+--------------------------------------------------------------------------------

haskell/src/Main.hs

@@ -8,8 +8,11 @@ import qualified Data.Map as Map
 
 import Witness
 import Parser
+import Graph
+import JSON
 
 --------------------------------------------------------------------------------
+{-
 
 (~>) :: String -> a -> (String, a)
 (~>) = (,)
@@ -22,13 +25,15 @@ testInputs = Map.fromList
   , "b" ~> [0xff02]
   ]
 
+-}
 --------------------------------------------------------------------------------
 
 main :: IO ()
 main = do
-  Right graph <- parseGraphFile "../tmp/graph2.bin"
+  Right graph <- parseGraphFile "../../tmp/graph4.bin"
   putStrLn ""
-  print graph
+  inputs <- loadInputJsonFile "../../tmp/input4.json"
-  let wtns = witnessCalc testInputs graph
+  print (inputSignals $ graphMeta graph)
+  let wtns = witnessCalc inputs graph
   putStrLn ""
   print wtns