Change syntax for function and return types

README.md

@@ -6,8 +6,8 @@ Inspired by F# and Haskell, it aims to deliver satisfactory functional programmi
 ```julia
 struct Person = (name: String, age: Int)
 
-let greet (p: Person) => IO = println "Hello " : p.name
-let main => IO = do
+let greet (p: Person): IO = println "Hello " : p.name
+let main: IO = do
     let person = Person { name: "Lily", age: 22 }
     greet person
 end

examples/bottles.in

@@ -1,4 +1,4 @@
-let bottles (i: Int) => IO = do
+let bottles (i: Int) : IO = do
     if i > 0 then do
         println ^i : " bottles of beer on the wall, " : ^i : " bottles of beer."
         println "Take one down and pass it around, " : ((i) - 1) as String : " bottles of beer on the wall.\n"
@@ -9,6 +9,6 @@ let bottles (i: Int) => IO = do
     end
 end
 
-let main => IO = do
+let main : IO = do
     bottles 99
 end

examples/casting.in

@@ -2,7 +2,7 @@ external "__default" = do
     sin :: Double -> Double
 end
 
-let main => IO = do
+let main : IO = do
     let tick = $20
     println 100.0 as Double * (sin (tick as Double))
 end

examples/cities.in

@@ -1,4 +1,4 @@
-# let main => IO = do
+# let main : IO = do
   let cities = ["London", "Oslo", "Paris", "Amsterdam", "Berlin"]
   let visited = ["Berlin", "Oslo"]
   println map (\a -> "I still need to visit " : a : "!" : "\n"), ((cities)-(visited))

examples/ffi_strlen.in

@@ -2,6 +2,6 @@ external "__default" = do
     strlen :: String -> Int
 end
 
-let main => IO = do
+let main : IO = do
     println strlen "Hello, World!\n"
 end

examples/fib.in

@@ -1,9 +1,9 @@
-let fib (0: Int) => Int = 0
-let fib (1: Int) => Int = 1
-let fib (n: Int) => Int = (fib ((n) - 1)) + (fib ((n) - 2))
+let fib (0: Int) : Int = 0
+let fib (1: Int) : Int = 1
+let fib (n: Int) : Int = (fib ((n) - 1)) + (fib ((n) - 2))
 
 #
-# let fib (n:Int) => Int = do
+# let fib (n:Int) : Int = do
 #     if n == 0 then
 #         0
 #     else if n == 1 then
@@ -16,6 +16,6 @@ let fib (n: Int) => Int = (fib ((n) - 1)) + (fib ((n) - 2))
 #         end
 # end
 
-let main => IO = do
+let main : IO = do
     println fib 12
 end

examples/generics.in

@@ -10,15 +10,15 @@ trait Number
 impl Number for Int
 impl Number for Float
 
-let kiss<T: Animal> (a: T b: T) => IO = do
+let kiss<T: Animal> (a: T b: T) : IO = do
     println a.name
 end
 
-let bla<T: Number> (a: T b: T) => T = do
+let bla<T: Number> (a: T b: T) : T = do
     a + b
 end
 
-let main => IO = do
+let main : IO = do
     let a = Dog { name: "dog" }
     let b = Cat { name: "cat" }
     let square (x: Int) = x * x

examples/guess.in

@@ -1,4 +1,4 @@
-let main => IO = do
+let main : IO = do
     let number = randomInt 1, 10
     println "Guess a number between 1 and 10"
     let guess = $getLine

examples/kitchen-sink.in

@@ -1,3 +1,3 @@
-let main => IO = do
+let main : IO = do
   let bla = \x -> x
 end

examples/lambdas.in

@@ -1,4 +1,4 @@
-let main => IO = do
+let main : IO = do
     let square (x:Int) = x * x
     let squareAll (xs:[Int]) = square 2
     let strict = $12

examples/pi.in

@@ -19,6 +19,6 @@ pi n = do
   4.0 * rsum
 end
 
-let main => IO = do
+let main : IO = do
   println pi 4000.0
 end

examples/raylib.in

@@ -30,7 +30,7 @@ let screenHeight = 450
 struct RaylibColor = (r: Char, g: Char, b: Char, a: Char)
 struct Vector3 = (x: Float, y: Float, z: Float)
 /* test */
-let loop (tick: Int) => IO = do
+let loop (tick: Int) : IO = do
     BeginDrawing
     ClearBackground 0
     times 7, (\i -> do
@@ -48,7 +48,7 @@ let loop (tick: Int) => IO = do
     else do
     end
 end
-let main => IO = do
+let main : IO = do
     InitWindow screenWidth, screenHeight, "Hello Indigo"
     SetTargetFPS 60
     loop 0

examples/state.in

@@ -8,19 +8,21 @@ end
 
 `:=` :: String -> Any -> State
 `:=` n v = do
-  if n == "x" then do
-    State{x: v}
-  else do
-    State{y: v}
-  end
+  update State{}, n, v
 end
 
 testState :: State
 testState = do
    "x" := 123
    "y" := 4562
    "x" := 1232
+   # liftM (println "Hello, world!")
 end
 
 main :: IO
-main = println testState
+# main = println testState
+main = do
+  testCase "abc", (\x -> do
+    assertEquals "x", "y"
+  end)
+end

examples/sum.in

@@ -3,7 +3,7 @@ mysum :: [Float] -> Float
 mysum [] = 0.0
 mysum (x:xs) = x + mysum xs
 
-let main => IO = do
+let main : IO = do
     let xs = range 1.0,100.0,2.0
     # print (sum xs)
     print mysum xs

examples/sum2.in

@@ -3,7 +3,7 @@ mysum :: [Float] -> Float
 mysum [] = 0.0
 mysum (x:xs) = x + mysum xs
 
-let main => IO = do
+let main : IO = do
     let xs = range 1.0,100.0,2.0
     # print (sum xs)
     print mysum xs

examples/sum_types.in

@@ -8,11 +8,11 @@ struct Car = ()
 impl Animal for Cat
 impl Animal for Dog
 
-let pet (a: Animal) => IO = do
+let pet (a: Animal) : IO = do
     println "petting animal"
 end
 
-let main => IO = do
+let main : IO = do
     pet Cat {}
     pet Dog {}
     pet Car {}

examples/traits.in

@@ -10,7 +10,7 @@ impl Animal for Cat = do
     makeNoise self = println "Meow"
 end
 
-let main => IO = do
+let main : IO = do
     makeNoise (Dog {})
     makeNoise (Cat {})
 end

lib/AST.hs

@@ -162,8 +162,8 @@ instance Show Type where
     show Any = "Any"
     show None = "None"
     show Unknown = "Unknown"
-    show (Fn fnArgs fnRet) = "Fn{" ++ show fnArgs ++ " -> " ++ show fnRet ++ "}"
-    show (List t) = "List{" ++ show t ++ "}"
+    show (Fn fnArgs fnRet) = "(" ++ show fnArgs ++ " -> " ++ show fnRet ++ ")"
+    show (List t) = "[" ++ show t ++ "]"
     show (StructT structName) = structName
     show Self = "Self"
 

lib/BytecodeCompiler.hs

@@ -596,13 +596,11 @@ compileExpr (Parser.Import{objects = o, from = from, as = as, qualified = qualif
     let expr = case parseProgram (T.pack i) Parser.initCompilerFlags{Parser.needsMain = False} of -- FIXME: pass on flags
             Left err -> error $ "Parse error: " ++ errorBundlePretty err
             Right (Parser.Program exprs) -> exprs
-    let p =
-            if qualified || isJust as
-                then do
-                    let alias = if qualified then from else fromJust as
-                    concatMapM (`compileExpr` expectedType) (map (`mangleAST` alias) expr)
-                else concatMapM (`compileExpr` expectedType) expr
-    p >>= \p' -> return p'
+    if qualified || isJust as
+        then do
+            let alias = if qualified then from else fromJust as
+            concatMapM (`compileExpr` expectedType) (map (`mangleAST` alias) expr)
+        else concatMapM (`compileExpr` expectedType) expr
   where
     mangleAST :: Parser.Expr -> String -> Parser.Expr
     mangleAST (Parser.FuncDec name types _) alias = Parser.FuncDec (alias ++ "@" ++ name) types []

lib/Parser.hs

@@ -226,12 +226,10 @@ validType =
             keyword "Any"
             return Any
         <|> do
-            keyword "Fn"
-            curlyBrackets $ do
+            parens $ do
                 args <- sepBy validType (symbol "->")
-                symbol "=>"
-                ret <- validType
-                return Fn{args = args, ret = ret}
+                let ret = last args
+                return $ Fn args ret
         <|> do
             squareBrackets $ do
                 List <$> validType
@@ -338,7 +336,7 @@ combinedFunc = do
     name <- identifier <|> gravis <?> "function name"
     generics <- (fromMaybe [] <$> optional generic) <?> "function generics"
     (args, argTypes) <- (parens argsAndTypes <|> argsAndTypes) <?> "function arguments"
-    returnType <- optional (symbol "=>" >> validType <?> "return type") <?> "return type"
+    returnType <- optional (symbol ":" >> validType <?> "return type") <?> "return type"
     symbol "="
     body <- recover expr <?> "function body"
     return $ Function [FuncDef name args body] (FuncDec name (argTypes ++ [fromMaybe Any returnType]) generics)