X-Git-Url: http://git.lukelau.me/?a=blobdiff_plain;f=AST.hs;h=1e505af4f47116e401e2523f10c90ac1c466c360;hb=8d014ae9c14ab12436acad496ba2726e39b4d69a;hp=dfa43b7c60c0d0ced86a73268167b1b9584b9d74;hpb=4d1dcdc8a1187df7d2981d426f57f79be922358d;p=kaleidoscope-hs.git

diff --git a/AST.hs b/AST.hs
index dfa43b7..1e505af 100644
--- a/AST.hs
+++ b/AST.hs
@@ -8,6 +8,7 @@ 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
@@ -17,7 +18,10 @@ 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
@@ -38,6 +42,14 @@ instance Read Expr where
                         sepBy (readS_to_P reads)
                               (skipSpaces >> char ',' >> skipSpaces)
             return (Call func params)
+          parseIf = do
+            lift $ skipSpaces >> string "if" >> skipSpaces
+            cond <- readPrec
+            lift $ skipSpaces >> string "then" >> skipSpaces
+            thenE <- readPrec
+            lift $ skipSpaces >> string "else" >> skipSpaces
+            elseE <- readPrec
+            return (If cond thenE elseE)
             
 data Prototype = Prototype String [String]
   deriving Show