Generate code for if statements

[kaleidoscope-hs.git] / AST.hs

diff --git a/AST.hs b/AST.hs
index e491b648a7d45f7bd3b419b0e3ff6a8c215cbd83..ae18a52347ce91c37336a06f891bae690ba691ec 100644 (file)
--- a/AST.hs
+++ b/AST.hs
@@ -4,9 +4,11 @@ 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
@@ -15,7 +17,11 @@ data BinOp = Add | Sub | Mul | Cmp Ordering
 instance Read Expr where
   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
@@ -24,12 +30,24 @@ instance Read Expr where
           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