Minor improvements

4 files changed, 73 insertions, 18 deletions

diff --git a/README.md b/README.md
index d3de308..4bc4490 100644
--- a/README.md
+++ b/README.md
@@ -115,7 +115,7 @@ You can try these by experimenting in the REPL or by running them as a
 file. Note, however, that you need an equal sign between the function
 name and its definition if you’re using the REPL.
 
-Plain execution without any predefined functions:
+#### Plain execution without any predefined functions
 
     # this is a comment
     # we now define a function returning a ternary 1
@@ -123,31 +123,61 @@ Plain execution without any predefined functions:
 
     # we can use the function in all functions below its definition
     get-one2 get-one
-    :test (get-one2 =? (+1)) (T)
+
+    :test (get-one2) (+1)
+
+    # indenting acts similar to Haskell's where statement
+    get-one3 foo
+        bar (+1)
+        foo bar
 
     # equivalent of λx.x
     id [0]
 
-    # equivalent of (λx.x) (λx.λy.x) = λx.λy.x
+    # testing equivalent of (λx.x) (λx.λy.x) = λx.λy.x
     :test (id [[1]]) ([[1]])
 
+    # prefix function definition
+    !( [[1]]
+
+    # use prefix function !
+    :test (![0]) ([[0]])
+
+    # infix function definition
+    (<>) [[0 1]]
+
+    # use infix function <>
+    :test ([[0]] <> [[1]]) ([[1]] [[0]])
+
     # multiple arguments
-    set-of-three [[[[0 1 2 3]]]]
     number-set set-of-three (+1) (+2) (+3)
+        set-of-three [[[[0 1 2 3]]]]
+
     access-first [0 [[[0]]]]
 
-    :test ((access-first number-set) =? (+1)) (T)
+    :test (access-first number-set) (+1)
 
     # endless loop using omega combinator
-    om [0 0]
-    nom om
     main om nom
+        om [0 0]
+        nom om
 
     # you may have realized you can't easily operate with numbers
     # or anything else really without writing crazy functions
     # -> luckily the standard library defines many standard operations!
 
-Using standard library:
+#### Using standard library
+
+“Hello world” program using IO:
+
+    :import std/List .
+
+    main [("Hello " ++ 0) ++ "!\n"]
+
+You can then use `printf "world" | bruijn file.bruijn` to get “Hello
+world!”
+
+Some other great functions:
 
     :import std/Logic .
     :import std/Combinator .
@@ -156,11 +186,12 @@ Using standard library:
     :import std/Pair .
 
     # pairs with some values
-    me [[[1]]]
-    you [[[2]]]
     love pair me you
-    :test (fst love) (me)
-    :test (snd love) (you)
+        me [[[1]]]
+        you [[[2]]]
+
+    :test (fst love) ([[[1]]])
+    :test (snd love) ([[[2]]])
 
     # options
     :test (map inc (some (+1))) (some (+2))
@@ -168,6 +199,7 @@ Using standard library:
 
     # numerical operations
     five --(((+8) + (-4)) - (-2))
+
     not-five? [if (0 =? (+5)) F T]
 
     :test (not-five? five) (F)
@@ -179,7 +211,7 @@ Using standard library:
 
     :test (main) (F)
 
-    # read the files in std/ for an overview of all functions/libraries
+Read the files in std/ for an overview of all functions/libraries.
 
 ### Compilation to BLC
 
diff --git a/src/Eval.hs b/src/Eval.hs
index 445e41d..4051643 100644
--- a/src/Eval.hs
+++ b/src/Eval.hs
@@ -41,7 +41,7 @@ loadFile path conf = do
   f <- try $ readFile path :: IO (Either IOError String)
   case f of
     Left exception ->
-      print (ContextualError (ImportError $ show (exception :: IOError)) (Context "" (nicePath conf))) >> pure (EnvState $ Environment [])
+      print (ContextualError (ImportError $ show (exception :: IOError)) (Context "" $ nicePath conf)) >> pure (EnvState $ Environment [])
     Right f' -> eval (filter (not . null) $ split "\n\n" f')
                        (EnvState $ Environment [])
                        (conf { isRepl = False, evalPaths = (path : (evalPaths conf)) })
@@ -117,7 +117,7 @@ evalInstruction (ContextualInstruction instr inp) s@(EnvState env) rec conf = ca
     let
       (res, env') = evalDefine name e subEnv `runState` env
      in  case res of
-          Left  err -> print (ContextualError err (Context inp (nicePath conf))) >> pure s -- don't continue
+          Left  err -> print (ContextualError err $ Context inp $ nicePath conf) >> pure s -- don't continue
           Right _   -> if isRepl conf
             then (putStrLn $ name <> " = " <> show e)
               >> return (EnvState env')
@@ -127,7 +127,7 @@ evalInstruction (ContextualInstruction instr inp) s@(EnvState env) rec conf = ca
     lib           <- getDataFileName path -- TODO: Use actual lib directory
     exists        <- doesFileExist lib
     actual        <- pure $ if exists then lib else path
-    if (actual `elem` evalPaths conf) then (print (ContextualError (ImportError path) (Context inp (nicePath conf))) >> pure s) else do
+    if actual `elem` evalPaths conf then print (ContextualError (ImportError path) (Context inp $ nicePath conf)) >> pure s else do
       EnvState env' <- loadFile actual (conf { nicePath = path }) -- TODO: Fix wrong `within` in import error
       let prefix | null namespace   = takeBaseName path ++ "."
                  | namespace == "." = ""
@@ -147,6 +147,8 @@ evalInstruction (ContextualInstruction instr inp) s@(EnvState env) rec conf = ca
                   <> (show reduced)
                   <> " "
                   <> (humanifyExpression reduced)
+                  <> " "
+                  <> (matchingFunctions reduced env)
                 where reduced = reduce e'
             )
           >> rec s conf
@@ -173,7 +175,7 @@ eval [""] s _ = return s
 eval (block : bs) s conf =
   handleInterrupt (putStrLn "<aborted>" >> return s)
     $ case parse blockParser "" block of
-        Left  err   -> print (ContextualError (SyntaxError $ printBundle err) (Context "" (nicePath conf))) >> eval bs s conf
+        Left  err   -> print (ContextualError (SyntaxError $ printBundle err) (Context "" $ nicePath conf)) >> eval bs s conf
         Right instr -> evalInstruction instr s (eval bs) conf
   where blockParser = if isRepl conf then parseReplLine else parseBlock 0
 
diff --git a/src/Helper.hs b/src/Helper.hs
index eb41673..47c106d 100644
--- a/src/Helper.hs
+++ b/src/Helper.hs
@@ -178,6 +178,15 @@ decodeStdout e = do
 
 ---
 
+lookupValues :: (Eq b) => b -> [(a, b)] -> [a]
+lookupValues _ [] = []
+lookupValues key ((x, y) : xys) | key == y  = x : lookupValues key xys
+                                | otherwise = lookupValues key xys
+
+matchingFunctions :: Expression -> Environment -> String
+matchingFunctions e (Environment env) =
+  intercalate ", " $ nub $ lookupValues e (map fst env)
+
 -- TODO: Expression -> Maybe Char is missing
 maybeHumanifyExpression :: Expression -> Maybe String
 maybeHumanifyExpression e = ternaryToDecimal e <|> decodeStdout e
diff --git a/std/Church.bruijn b/std/Church.bruijn
index 412938a..bba2784 100644
--- a/std/Church.bruijn
+++ b/std/Church.bruijn
@@ -1,7 +1,19 @@
 # MIT License, Copyright (c) 2022 Marvin Borner
 
 zero [[0]]
-succ [[[1 (2 1 0)]]]
+
+inc [[[1 (2 1 0)]]]
+
+++( inc
+
 add [[[[3 1 (2 1 0)]]]]
+
+(+) add
+
 mul [[[2 (1 0)]]]
+
+(*) mul
+
 exp [[0 1]]
+
+(^) exp