added constructor for declaration with default value

diff --git a/Abssyntax.hs b/Abssyntax.hs
index ec85c8d619730b34e85d5e00a39f4a562e995d06..d9fc3445b15970a66b0ac32ce0d1ca796c5648a8 100644 (file)
--- a/Abssyntax.hs
+++ b/Abssyntax.hs
@@ -16,11 +16,12 @@ data Stms =
 data Stm =
    SExp Exp
  | SBlock [Stm]
+ | SDecl Type Ident Exp
+ | SDeclD Type Ident
  | SWhile Exp Stm
  | SIf Exp Stm Stm
  | SPrint Exp
  | SNoop
- | SDecl Type Ident Exp
   deriving (Eq,Ord,Show)
 
 data Exp =

diff --git a/Compile.hs b/Compile.hs
index 69edecd879be433bab4f32259f8f0f79d2af0d41..0e1cf22a1c0b0239f43af889962496e9ce2c37f7 100644 (file)
--- a/Compile.hs
+++ b/Compile.hs
@@ -36,4 +36,8 @@ compileStm (SIf b s s') = "if("++compileExp b++")"++compileStm s++" \nelse "++co
 compileStm (SPrint e) = "printf(\"%d\\n\","++compileExp e++");\n"
 compileStm (SBlock ss) = "{\n"++concat (map (("\t"++).compileStm) ss)++"\n}\n"
 compileStm (SWhile e s) = "while("++compileExp e++")"++compileStm s
+compileStm (SDeclD t i) = compileStm (SDecl t i $ case t of
+       TInt -> EInt 0
+       TBool -> EBool False
+       )
 compileStm (SDecl t (Ident i) e) = "int "++i++"="++compileExp e++";\n"

diff --git a/Docsyntax.tex b/Docsyntax.tex
index e0d2758fa311ea43031e94b4f8e449d033227bba..d978641a5ecfd0855d40eb5228723db4ecda8e1a 100644 (file)
--- a/Docsyntax.tex
+++ b/Docsyntax.tex
@@ -84,10 +84,8 @@ All other symbols are terminals.\\
 \begin{tabular}{lll}
 {\nonterminal{Stm}} & {\arrow}  &{\nonterminal{Exp}} {\terminal{;}}  \\
  & {\delimit}  &{\terminal{\{}} {\nonterminal{ListStm}} {\terminal{\}}}  \\
- & {\delimit}  &{\terminal{int}} {\nonterminal{Ident}} {\terminal{{$=$}}} {\nonterminal{Exp}} {\terminal{;}}  \\
- & {\delimit}  &{\terminal{bool}} {\nonterminal{Ident}} {\terminal{{$=$}}} {\nonterminal{Exp}} {\terminal{;}}  \\
- & {\delimit}  &{\terminal{int}} {\nonterminal{Ident}} {\terminal{;}}  \\
- & {\delimit}  &{\terminal{bool}} {\nonterminal{Ident}} {\terminal{;}}  \\
+ & {\delimit}  &{\nonterminal{Type}} {\nonterminal{Ident}} {\terminal{{$=$}}} {\nonterminal{Exp}} {\terminal{;}}  \\
+ & {\delimit}  &{\nonterminal{Type}} {\nonterminal{Ident}} {\terminal{;}}  \\
  & {\delimit}  &{\terminal{while}} {\terminal{(}} {\nonterminal{Exp}} {\terminal{)}} {\nonterminal{Stm}}  \\
  & {\delimit}  &{\terminal{if}} {\terminal{(}} {\nonterminal{Exp}} {\terminal{)}} {\nonterminal{Stm}} {\terminal{else}} {\nonterminal{Stm}}  \\
  & {\delimit}  &{\terminal{if}} {\terminal{(}} {\nonterminal{Exp}} {\terminal{)}} {\nonterminal{Stm}}  \\

diff --git a/Interpret.hs b/Interpret.hs
index 8ac65bf247c9acf10699573d40669e65ca43782b..fd04dcd722d9e33d8b65a70c292c96bd161e48e4 100644 (file)
--- a/Interpret.hs
+++ b/Interpret.hs
@@ -109,6 +109,10 @@ execute (SBlock ss) = pushAndPop $ mapM execute ss
 execute (SWhile e s) = do
        (VBool b) <- eval e
        if b then pushAndPop (execute s) >> execute (SWhile e s) else return ()
+execute (SDeclD t i) = execute (SDecl t i $ case t of
+       TInt -> EInt 0
+       TBool -> EBool False
+       )
 execute (SDecl t i e) =do
        e' <- eval e
        (m:ms) <- get

diff --git a/Parsyntax.y b/Parsyntax.y
index 02e94b0bc4803b1a1ac5ca5f525de11cc3e348f1..6613fa351325648a0f3cd8bff19ae301e6fbc25b 100644 (file)
--- a/Parsyntax.y
+++ b/Parsyntax.y
@@ -71,10 +71,8 @@ Stms : ListStm { Program (reverse $1) }
 Stm :: { Stm }
 Stm : Exp ';' { SExp $1 } 
   | '{' ListStm '}' { SBlock (reverse $2) }
-  | 'int' Ident '=' Exp ';' { declIntE_ $2 $4 }
-  | 'bool' Ident '=' Exp ';' { declBoolE_ $2 $4 }
-  | 'int' Ident ';' { declInt_ $2 }
-  | 'bool' Ident ';' { declBool_ $2 }
+  | Type Ident '=' Exp ';' { SDecl $1 $2 $4 }
+  | Type Ident ';' { SDeclD $1 $2 }
   | 'while' '(' Exp ')' Stm { SWhile $3 $5 }
   | 'if' '(' Exp ')' Stm 'else' Stm { SIf $3 $5 $7 }
   | 'if' '(' Exp ')' Stm { if_ $3 $5 }
@@ -154,10 +152,6 @@ happyError ts =
   Bad $ "syntax error at " ++ tokenPos ts ++ if null ts then [] else (" before " ++ unwords (map prToken (take 4 ts)))
 
 myLexer = tokens
-declIntE_ x_ e_ = SDecl TInt x_ e_
-declBoolE_ x_ e_ = SDecl TBool x_ e_
-declInt_ x_ = SDecl TInt x_ (EInt 0)
-declBool_ x_ = SDecl TBool x_ (EBool False)
 if_ e_ s_ = SIf e_ s_ SNoop
 compExp_ e1_ o_ e2_ = BiOpExp e1_ o_ e2_
 op1_ e1_ o_ e2_ = BiOpExp e1_ o_ e2_

diff --git a/Printsyntax.hs b/Printsyntax.hs
index ff0128e8d8f68a0398d6b154dc5478968c19a4c6..d1b4c4962d5b0a37e4d40bfec23c249040213763 100644 (file)
--- a/Printsyntax.hs
+++ b/Printsyntax.hs
@@ -102,11 +102,12 @@ instance Print Stm where
   prt i e = case e of
    SExp exp -> prPrec i 0 (concatD [prt 0 exp , doc (showString ";")])
    SBlock stms -> prPrec i 0 (concatD [doc (showString "{") , prt 0 stms , doc (showString "}")])
+   SDecl type' id exp -> prPrec i 0 (concatD [prt 0 type' , prt 0 id , doc (showString "=") , prt 0 exp , doc (showString ";")])
+   SDeclD type' id -> prPrec i 0 (concatD [prt 0 type' , prt 0 id , doc (showString ";")])
    SWhile exp stm -> prPrec i 0 (concatD [doc (showString "while") , doc (showString "(") , prt 0 exp , doc (showString ")") , prt 0 stm])
    SIf exp stm0 stm -> prPrec i 0 (concatD [doc (showString "if") , doc (showString "(") , prt 0 exp , doc (showString ")") , prt 0 stm0 , doc (showString "else") , prt 0 stm])
    SPrint exp -> prPrec i 0 (concatD [doc (showString "print") , prt 0 exp , doc (showString ";")])
    SNoop  -> prPrec i 0 (concatD [])
-   SDecl type' id exp -> prPrec i 0 (concatD [prt 0 type' , prt 0 id , doc (showString "=") , prt 0 exp , doc (showString ";")])
 
   prtList es = case es of
    [] -> (concatD [])

diff --git a/Skelsyntax.hs b/Skelsyntax.hs
index bc9bc0cd636ac74859db584ea12a06693837fbec..9f3feab046e4624d3c594fad502219d14a04f1a6 100644 (file)
--- a/Skelsyntax.hs
+++ b/Skelsyntax.hs
@@ -35,11 +35,12 @@ transStm :: Stm -> Result
 transStm x = case x of
   SExp exp  -> failure x
   SBlock stms  -> failure x
+  SDecl type' id exp  -> failure x
+  SDeclD type' id  -> failure x
   SWhile exp stm  -> failure x
   SIf exp stm0 stm  -> failure x
   SPrint exp  -> failure x
   SNoop  -> failure x
-  SDecl type' id exp  -> failure x
 
 
 transExp :: Exp -> Result

diff --git a/Typecheck.hs b/Typecheck.hs
index cdba298976ad2aefcecaf7e71a52b74ebb6415f0..70aad706a88cfc5b38a1863744ccce563772e490 100644 (file)
--- a/Typecheck.hs
+++ b/Typecheck.hs
@@ -75,13 +75,18 @@ typeCheckStm (SIf e s s') = do
 typeCheckStm (SWhile e s) = do
        TBool <- typeCheckExp e
        pushAndPop $ typeCheckStm s
+typeCheckStm (SDeclD t i) = addVariable i t
 typeCheckStm (SDecl t i e) = do
        t2 <- typeCheckExp e
        assert (t == t2) $ "Illegal to assign an expression of type "++show t2++" to variable "++show i++" of type "++show t
+       addVariable i t
+typeCheckStm (SPrint e) = do
+       typeCheckExp e
+       return ()
+
+addVariable :: (MonadState Types m) => Ident -> Type -> m ()
+addVariable i t = do
        (m:ms) <- get
        case insertLookupWithKey (\k a1 a2 -> a1) i t m of
                (Nothing,m') -> put (m':ms)
                _ -> fail $ "Duplicate variable declaration: "++show i
-typeCheckStm (SPrint e) = do
-       typeCheckExp e
-       return ()

diff --git a/syntax.cf b/syntax.cf
index 26408246305de004f448085d22bb717adca8736b..0347ce56e2982362825fb40f7ec2582f778e9690 100644 (file)
--- a/syntax.cf
+++ b/syntax.cf
@@ -13,14 +13,8 @@ Program.  Stms ::= [Stm] ;
 
 SExp.      Stm      ::= Exp ";" ;
 SBlock.    Stm      ::= "{" [Stm] "}" ;
-declIntE.  Stm      ::= "int" Ident "=" Exp ";" ;
-declBoolE. Stm      ::= "bool" Ident "=" Exp ";" ;
-define declIntE x e = SDecl TInt x e;
-define declBoolE x e = SDecl TBool x e;
-declInt. Stm ::= "int" Ident ";" ;
-declBool. Stm ::= "bool" Ident ";" ;
-define declInt x  = SDecl TInt x (EInt 0);
-define declBool x = SDecl TBool x (EBool False);
+SDecl. Stm ::= Type Ident "=" Exp ";" ;
+SDeclD. Stm ::= Type Ident ";" ;
 
 
 SWhile.   Stm      ::= "while" "(" Exp ")" Stm ;
@@ -96,7 +90,6 @@ internal BiOpExp. Exp ::= Exp Op Exp ;
 internal EPost. Exp ::= Ident Op1 ;
 
 internal SNoop. Stm ::= ;
-internal SDecl. Stm ::= Type Ident "=" Exp ";" ;
 
 comment "/*" "*/" ;
 comment "//" ;