module Data.String.Ubc.Parse.Struct
( Struct(..)
, parseStruct
)
where

import Text.Parsec

import Data.String.Ubc.Parse.StructVariable (StructVariable)
import Data.String.Ubc.Parse.ParserState (ParserState)
import Data.String.Ubc.Parse.Error.StructError (StructError)
import Data.String.Ubc.Parse.StructScope (StructScope(..))
import Data.String.Ubc.Parse.Scope (Scope(..))

import qualified Data.String.Ubc.Parse.Language as UbcLanguage
import qualified Data.String.Ubc.Parse.Error.StructError as StructError
import qualified Data.String.Ubc.Parse.StructScope as StructScope
import qualified Data.String.Ubc.Parse.ParserState as ParserState

data Struct = Struct 
        { name :: String
        , memberVariables :: [StructVariable]
        }

parseStruct :: Monad m => ParsecT String ParserState m (Either StructError Struct)
parseStruct = do
        _ <- UbcLanguage.reserved "struct"

        structName <- choice 
                [ UbcLanguage.identifier >>= return . Right
                , getPosition >>= return . Left . StructError.MissingNameError
                ]
        let structScope = StructScope
                { structName = either (const Nothing) (Just) structName 
                , errors = []
                }

        updateState (ParserState.pushScope . ScopeStruct $ structScope)

        openingBrace <- choice
                [ UbcLanguage.symbol "{" >>= return . Right
                , getPosition >>= return . Left . StructError.MissingBraceError . Left
                ]

        closingBrace <- choice
                [ UbcLanguage.symbol "}" >>= return . Right
                , getPosition >>= return . Left . StructError.MissingBraceError . Right
                ]
        return $ Right $ Struct "" []