Bugfix: vmcompiler: parse numeric offset in static segment

Apparently, numeric arguments to push/pop static are valid,
so I prefix them with 'STATIC_' at the parsing stage

src/Nand2Tetris/VM.hs

@@ -129,7 +129,7 @@ parseInstruction =
                parseSegmentInt "this"  SThis,
                parseSegmentInt "that"  SThat,
                parseSegmentInt "constant" SConstant,
-               (string "static" *> space1) *> (SStatic <$> parseId),
+               (string "static" *> space1) *> (SStatic <$> (try parseId <|> parseStaticOffset)),
                parseSegmentInt "pointer" SPointer,
                parseSegmentInt "temp" STemp
              ]
@@ -141,6 +141,10 @@ parseInstruction =
       hs <- many (alphaNumChar <|> char '.' <|> char '_')
       return $ T.pack (h : hs)
 
+    parseStaticOffset :: Parser T.Text
+    parseStaticOffset = do
+      h <- L.decimal
+      return $ "STATIC_" <> (T.pack . show) h
 
     parseSegmentInt :: T.Text -> (Int -> Segment) -> Parser Segment
     parseSegmentInt sname f = try $ do