Lex | % ! 包围，里面内容是一些定义，格式为 a b。

If you generate a reentrant scanner, you must define its prototype to include a parameter named yyscanner of type yyscan_t. And you need to call the scanner with that argument. You cannot substitute some type you have defined for the yyscan_t argument, because your type does not include the data members which the flex-generated scanner uses. And you must use the name yyscanner because that's how the code generated by Flex references the data members.

If you want a yylex which only needs one argument, the "official" way to do that is to put your data members (or a pointer to them) into the "extra data" in the yyscan_t. But it might be easier to just use two arguments.

Your grammar is ambiguous; E OPERATOR E can apply to a + b * c in two ways (with two different meanings), depending on whether the first E is used to derive a or a + b.

Ambiguous grammars always have conflicts, because there is always a point in the parse where the parser could use more than one conflicting action. (The inverse is not true: a grammar with a conflict is not necessarily ambiguous. That will come later in your course, I suppose.)

So if you want to eliminate the conflict, you need to choose which of the two possible derivations above is correct (and all the similar ambiguities, but since they all have the same cause a relatively simple fix is possible).

I believe all you have to do is configure the HOME variable to your command so it looks like:

Ok, it doesn't seem to matter whether I use ".45Fall_2222" or "*45Fall_2222", both return the same result. The problem turned out to be with the read_data function. I had originally tried this:

I believe this is what you want

The way I do it is by "injecting" something that returns the core object:

Instead of doing:

Lex (including the Ply variety) builds lexical analysers, not regular expression searchers. Unlike a regular expression library, which generally attempts to scan the entire input to find a pattern, lex tries to decide what pattern matches at the current input point. It then advances the input to the point immediately following, and tries to find the matching pattern at that point. And so on. Every character in the text is contained in some matched token. (Although some tokens might be discarded.)

You can actually take advantage of this fact to simplify your regular expressions. In this case, for example, since you can count on t_FL_COMMENT to match a comment which does occur at the beginning of a line, any other comment must be not at the start of a line. So no lookbehind is needed:

As the Ply documentation says (with an example):

4.5 Discarded tokens

To discard a token, such as a comment, simply define a token rule that returns no value. For example:

As far as I can see your issue is caused by the lack of word wrapping. Your last table row has a long uninterrupted string: the link with the UTM-tags. If you'd remove the utm-tags from it, the cropping would not persist.