第17章编译表达式，"并将其存储中previous字段中"修改->"并将其存储在previous字段中"

[Chanyon]

Just like in jlox, it steps forward through the token stream. It asks the scanner for the next token and stores it for later use. Before doing that, t takes the old current token and stashes that in a previous field.That will come in handy later so that we can get at the lexeme after we match a token.

就像在jlox中一样，该函数向前通过标识流。它会向扫描器请求下一个词法标识，并将其存储起来以供后面使用。在此之前，它会获取旧的current标识，并将其存储中previous字段中。这在以后会派上用场，让我们可以在匹配到标识之后获得词素。

• 加粗部分修改并将其存储在previous字段中

[GuoYaxiang]

可以自己fork工程，修改以后提交PR哦