Method readToken

src/parser/scanner.ts:108–336

()

	}

	private readToken(): Token {
		let hasLeftSpacing = false;

		while (true) {
			if (this.stream.eof) {
				return TOKEN(TokenKind.EOF, this.stream.getPos(), { hasLeftSpacing });
			}
			// skip spasing
			if (spaceChars.includes(this.stream.char)) {
				this.stream.next();
				hasLeftSpacing = true;
				continue;
			}

			// トークン位置を記憶
			const pos = this.stream.getPos();

			if (lineBreakChars.includes(this.stream.char)) {
				this.skipEmptyLines();
				return TOKEN(TokenKind.NewLine, pos, { hasLeftSpacing });
			}

			// noFallthroughCasesInSwitchと関数の返り値の型を利用し、全ての場合分けがreturnかcontinueで適切に処理されることを強制している
			// その都合上、break文の使用ないしこのswitch文の後に処理を書くことは極力避けてほしい
			switch (this.stream.char) {
				case '!': {
					this.stream.next();
					if (!this.stream.eof && (this.stream.char as string) === '=') {
						this.stream.next();
						return TOKEN(TokenKind.NotEq, pos, { hasLeftSpacing });
					} else {
						return TOKEN(TokenKind.Not, pos, { hasLeftSpacing });
					}
				}
				case '"':
				case '\'': {
					return this.readStringLiteral(hasLeftSpacing);
				}
				case '#': {
					this.stream.next();
					if (!this.stream.eof && (this.stream.char as string) === '#') {
						this.stream.next();
						if (!this.stream.eof && (this.stream.char as string) === '#') {
							this.stream.next();
							return TOKEN(TokenKind.Sharp3, pos, { hasLeftSpacing });
						} else {
							throw new AiScriptSyntaxError('invalid sequence of characters: "##"', pos);
						}
					} else if (!this.stream.eof && (this.stream.char as string) === '[') {
						this.stream.next();
						return TOKEN(TokenKind.OpenSharpBracket, pos, { hasLeftSpacing });
					} else {
						return TOKEN(TokenKind.Sharp, pos, { hasLeftSpacing });
					}
				}
				case '%': {
					this.stream.next();
					return TOKEN(TokenKind.Percent, pos, { hasLeftSpacing });