README.md and website example grammar doesn't handle leading digit for all idents in ident_list

[SeedyROM]

The current example grammar will allow for every ident after the first to start with a digit.

For instance "a1 2b" is a valid ident_list with the current grammar.

Wouldn't this make sense for the ident rule?

...
ident = { !digit ~ (alpha | digit)+ }

ident_list = _{ ident ~ (" " ~ ident)+ }

I'm new to PEG style grammars so maybe I'm wrong?

[Alextopher]

Commenting since it's a "good-first-issue".

The issue is correct the example grammar does allow every ident after the first to start with a digit. The text above the example in the REAME says as much (both Today and in Oct 2021).

The following is an example of a grammar for a list of alpha-numeric identifiers where the first identifier does not start with a digit:

So I believe this issue may be closed with wont-fix.

However, I don't think the confusion is unwarranted, I can not think of a time I wanted an "identifier list but the first identifier is not like the others." Looking at git blame I can see at some point in the past the example matched the suggested grammar.

I also recall discovering https://pest.rs, copying the example into the Editor, and feeling confused as to why a _ did not return an error while _ does. After reading the book I understand it's the lack of any EOI requirement.

Also, if we are switching things around like this then

ident_list = _{ ident ~ (" " ~ ident)+ }

should be

ident_list = _{ ident ~ (" " ~ ident)* }
                                     ^

If there is interest in updating the example I would be willing to create a draft PR. Otherwise, I think this issue should be closed.

[tomtau]

@Alextopher feel free to open PRs to improve the examples in README here and the book / site repositories.