X-Git-Url: http://git.lukelau.me/?a=blobdiff_plain;f=AST.hs;h=ae18a52347ce91c37336a06f891bae690ba691ec;hb=0d4ed473c520786af90ab70dac51451ea2b8b941;hp=5b22ea6c662714d483f1dd1ec51755e5f4b7dc7a;hpb=0d60a0af6b11db89bee6ee8377be3d3f0aae715e;p=kaleidoscope-hs.git

diff --git a/AST.hs b/AST.hs
index 5b22ea6..ae18a52 100644
--- a/AST.hs
+++ b/AST.hs
@@ -1,32 +1,75 @@
 module AST where
 
+import Data.Char
 import Text.Read 
 import Text.ParserCombinators.ReadP hiding ((+++), choice)
 
-data Expr = Num Float
+data Expr = Num Double
+          | Var String
           | BinOp BinOp Expr Expr
+          | Call String [Expr]
+          | If Expr Expr Expr
   deriving Show
 
 data BinOp = Add | Sub | Mul | Cmp Ordering
   deriving Show
 
 instance Read Expr where
-  readPrec = choice [ parseNum
+  readPrec = parens $ choice [ parseNum
+                             , parseVar
+                             , parseCall
+                             , parseIf
                              , parseBinOp "<" 10 (Cmp LT)
+                             , parseBinOp ">" 10 (Cmp GT)
+                             , parseBinOp "==" 10 (Cmp EQ)
                              , parseBinOp "+" 20 Add
                              , parseBinOp "-" 20 Sub
                              , parseBinOp "*" 40 Mul
                              ]
     where parseNum = Num <$> readPrec
-          -- use 'prec 1' and 'step' so that parsing 'a'
-          -- can only go one step deep, to prevent ininfite
-          -- recursion
+          parseVar = Var <$> lift (munch1 isAlpha)
           parseBinOp s prc op = prec prc $ do
             a <- step readPrec
-            lift $ do
-              skipSpaces
-              string s
-              skipSpaces
+            spaced $ string s
             b <- readPrec
             return (BinOp op a b)
+          parseCall = do
+            func <- lift (munch1 isAlpha)
+            params <- lift $ between (char '(') (char ')') $
+                        sepBy (readS_to_P reads)
+                              (skipSpaces >> char ',' >> skipSpaces)
+            return (Call func params)
+          parseIf = do
+            spaced $ string "if" 
+            cond <- readPrec
+            spaced $ string "then"
+            thenE <- readPrec
+            spaced $ string "else"
+            elseE <- readPrec
+            return (If cond thenE elseE)
+          spaced f = lift $ skipSpaces >> f >> skipSpaces
             
+data Prototype = Prototype String [String]
+  deriving Show
+
+instance Read Prototype where
+  readPrec = lift $ do
+    name <- munch1 isAlpha
+    params <- between (char '(') (char ')') $
+                sepBy (munch1 isAlpha) skipSpaces
+    return (Prototype name params)
+
+data AST = Function Prototype Expr
+         | Extern Prototype
+         | TopLevelExpr Expr
+  deriving Show
+
+instance Read AST where
+  readPrec = parseFunction +++ parseExtern +++ parseTopLevel
+    where parseFunction = do
+            lift $ string "def" >> skipSpaces
+            Function <$> readPrec <*> readPrec
+          parseExtern = do
+            lift $ string "extern" >> skipSpaces
+            Extern <$> readPrec
+          parseTopLevel = TopLevelExpr <$> readPrec