book - Learning Perl 6, 2018, brian d foy, O'Reilly

While I enjoyed the famous llama book Learning Perl (for Perl 5), coauthored by brian d foy, I couldn't put my finger on why his solo work Learning Perl 6 feels off.

Errata

• (2023-07-09) After spotting two bad errors regarding <ws> in the book - Parsing With Perl 6 Regexes and Grammars, 2017, Moritz Lenz, Apress book, I tried to look for and expected clarity in guidance from this book. Instead, I found what appears to be more confusing errors and terribly imprecise misused language.

First, <|wb>, according to official documentation, is wrong. It should be

<?wb> or the hard-to-understand <|w>.

Second, the comment "required between word characters, optional otherwise" is just plain wrong. It's confusing language. A word character should be [a-zA-Z0-9_] or any Unicode letter. If we take "Hello world!", "between word characters" therefore would mean any point where I added a ^:

H^e^l^l^o w^o^r^l^d!

Those points aren't places where whitespace is required. Quite the opposite.

What the author means to say is "between words" or more verbosely, "between a word character and a non-word character." If we ignore both ends, there are exactly two points where <ws> can occur:

Hello^world^!

!450

In terms of confusing writing, seriously I'm appalled, but one instance is forgivable. Will watch out for more.