示例#1
0
文件: Parse.cs 项目: Blecki/EtcScript
        public static Ast.ComplexString ParseComplexString(TokenStream Stream, ParseContext Context)
        {
            System.Diagnostics.Debug.Assert(Stream.Next().Type == TokenType.Dollar);
            var start = Stream.Next();

            Stream.PushState(TokenStreamState.ComplexString); //Enter complex string parsing mode

            Stream.Advance();
            if (Stream.Next().Type != TokenType.ComplexStringQuote)
                throw new CompileError("[015] Expected \"", Stream);
            Stream.Advance();

            var stringPieces = new List<Ast.Node>();

            while (Stream.Next().Type != TokenType.ComplexStringQuote)
            {
                if (Stream.Next().Type == TokenType.ComplexStringPart)
                {
                    stringPieces.Add(new Ast.StringLiteral(Stream.Next(), Stream.Next().Value));
                    Stream.Advance();
                }
                else if (Stream.Next().Type == TokenType.OpenBracket)
                {
                    Stream.PushState(TokenStreamState.Normal); //Make sure we are parsing normally for the
                    Stream.Advance(); //Skip the [						//embedded expression
                    stringPieces.Add(ParseExpression(Stream, Context, TokenType.CloseBracket));
                    if (Stream.Next().Type != TokenType.CloseBracket)	//Shouldn't be possible
                        throw new CompileError("[016] Expected ]", Stream);
                    Stream.PopState();	//Return to complex string parsing mode
                    Stream.Advance();
                }
                else
                    throw new InvalidProgramException();
            }

            Stream.PopState(); //Return to normal parsing mode
            Stream.Advance();

            return new Ast.ComplexString(start, stringPieces);
        }