and (|IdentifierDefinition|_|) tokens =
        let rec parseIdentifierTuple tokens (cont:IdentifierDefinition list) =
            match tokens with
            | Token.LParen (row,col) :: remainingTokens ->
                let remainingTokens,tuple = parseIdentifierTuple remainingTokens []
                let remainingTokens,RHS = parseIdentifierTuple remainingTokens (cont @ [IdentifierDefinition.TupleIdentifier tuple])
                (remainingTokens, RHS)
            | Token.Identifier (name,row,col) :: remainingTokens ->
                let identifier = IdentifierDefinition.Identifier (name,Unknown)
                match remainingTokens with
                | Token.Comma (row,col) :: remainingTokens ->
                    match remainingTokens with
                    | Token.Identifier _ :: _ | Token.LParen _ :: _ -> ()
                    | _ -> failwith <| errorMessage codeLines.[row] row col "Unexpected token after comma"
                    let remainingTokens,cont =  parseIdentifierTuple remainingTokens (cont @ [identifier])
                    (remainingTokens,cont)
                | Token.RParen (row,col) :: remainingTokens ->
                    match remainingTokens with
                    | Token.Comma (row,col) :: remainingTokens ->   (remainingTokens,cont @ [identifier])
                    | _ ->                                          (remainingTokens,cont @ [identifier])
                | _ ->
                    failwith <| errorMessage codeLines.[row] row col ("Unexpected token after " + name)
            | Token.RParen (row,col) :: remainingTokens ->
                (remainingTokens,cont)
        match tokens with
        | Token.LParen (row,col) :: remainingTokens ->
            let remainingTokens,tuple = parseIdentifierTuple remainingTokens []
            Some <| (remainingTokens, IdentifierDefinition.TupleIdentifier tuple)
        | Token.Identifier (name,row,col) :: remainingTokens->
            Some (remainingTokens, IdentifierDefinition.Identifier (name,Unknown))
        | _ -> None