add fifth exercise of lecture 5

1 files changed, 18 insertions, 7 deletions

diff --git a/lec05/Calc.hs b/lec05/Calc.hs
index 7502b5f..a38de57 100644
--- a/lec05/Calc.hs
+++ b/lec05/Calc.hs
@@ -2,18 +2,19 @@ module Calc where
 
 import ExprT
 import Parser
+import StackVM
 
 -- Exercise 1
 
 eval :: ExprT -> Integer
 eval (Lit n) = n
-eval (Add l r) = eval l + eval r
-eval (Mul l r) = eval l * eval r
+eval (ExprT.Add l r) = eval l + eval r
+eval (ExprT.Mul l r) = eval l * eval r
 
 -- Exercise 2
 
 evalStr :: String -> Maybe Integer
-evalStr s = case parseExp Lit Add Mul s of
+evalStr s = case parseExp Lit ExprT.Add ExprT.Mul s of
                  Nothing -> Nothing
                  Just t  -> Just (eval t)
 
@@ -26,8 +27,8 @@ class Expr a where
 
 instance Expr ExprT where
          lit = Lit
-         add = Add
-         mul = Mul
+         add = ExprT.Add
+         mul = ExprT.Mul
 
 reify :: ExprT -> ExprT
 reify = id
@@ -36,8 +37,8 @@ reify = id
 
 instance Expr Integer where
          lit x   = x
-         add l r = eval (Add (Lit l) (Lit r))
-         mul l r = eval (Mul (Lit l) (Lit r))
+         add l r = eval (ExprT.Add (Lit l) (Lit r))
+         mul l r = eval (ExprT.Mul (Lit l) (Lit r))
 
 instance Expr Bool where
          lit x
@@ -66,3 +67,13 @@ testInteger = testExp :: Maybe Integer
 testBool    = testExp :: Maybe Bool
 testMM      = testExp :: Maybe MinMax
 testSat     = testExp :: Maybe Mod7
+
+-- Exercise 5
+
+instance Expr Program where
+         lit x = [PushI x]
+         add l r = l ++ r ++ [StackVM.Add]
+         mul l r = l ++ r ++ [StackVM.Mul]
+
+compile :: String -> Maybe Program
+compile s = parseExp lit add mul s