added while looping construct

app/Parser.hs

@@ -11,6 +11,7 @@ data ZorthExpr = ZorthASTInteger Int
                | ZorthASTWord String
                | ZorthASTWordDecl (String,ZorthAST)
                | ZorthASTIfElse (ZorthAST,ZorthAST)
+               | ZorthASTWhile (ZorthAST,ZorthAST)
                deriving Show
 
 word1 :: Parser String
@@ -41,7 +42,6 @@ pZorthInteger :: Parser ZorthExpr
 pZorthInteger = do
     skipNonsenseSymbols
     i <- pZorthSignedInteger <|> pZorthUnsignedInteger 
-    eof <|> void nonsenseSymbol
     return i
 
 pZorthWord :: Parser ZorthExpr
@@ -64,8 +64,15 @@ pZorthIfElse = do
     elseBranch <- manyTill pZorthExpr (do { ZorthASTWord "fi" <- pZorthWord; return () })
     return $ ZorthASTIfElse (ifBranch,elseBranch)
 
+pZorthWhile :: Parser ZorthExpr
+pZorthWhile = do
+    ZorthASTWord "begin" <- pZorthWord
+    condition <- manyTill pZorthExpr (do { ZorthASTWord "while" <- pZorthWord; return () })
+    body <- manyTill pZorthExpr (do { ZorthASTWord "repeat" <- pZorthWord; return () })
+    return $ ZorthASTWhile (condition,body)
+
 pZorthExpr :: Parser ZorthExpr
-pZorthExpr = pZorthIfElse <|> pZorthWordDecl <++ pZorthInteger <++ pZorthWord
+pZorthExpr = pZorthWhile <|> pZorthIfElse <|> pZorthWordDecl <++ pZorthInteger <++ pZorthWord
 
 pZorth :: Parser ZorthAST 
 pZorth = some pZorthExpr