X-Git-Url: https://git.lukelau.me/?p=kaleidoscope-hs.git;a=blobdiff_plain;f=AST.hs;h=1e505af4f47116e401e2523f10c90ac1c466c360;hp=5b22ea6c662714d483f1dd1ec51755e5f4b7dc7a;hb=HEAD;hpb=d6cecbbf067560322e391363250fd3c5d45bfbec;ds=sidebyside

diff --git a/AST.hs b/AST.hs
index 5b22ea6..9ff555a 100644
--- a/AST.hs
+++ b/AST.hs
@@ -1,26 +1,31 @@
 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]
   deriving Show
 
 data BinOp = Add | Sub | Mul | Cmp Ordering
   deriving Show
 
 instance Read Expr where
-  readPrec = choice [ parseNum
+  readPrec = parens $ choice [ parseNum
+                             , parseVar
+                             , parseCall
                              , 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
@@ -29,4 +34,34 @@ instance Read Expr where
               skipSpaces
             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)
             
+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