Errata for Programming Ruby 1.9

#33198: It looks like you're trying to keep a clean set of numbered "tutclasses_##.rb" files. But it seems a little strange that we have a java class here in an .rb file.--Charlie O'Keefe

#33199: It looks like you're trying to have a cleanly numbered set of "tutclasses_##.rb" files, but in the example on this page we're calling the files by one set of names in the text (book_in_stock.rb, csv_reader.rb, and stock_stats.rb) and another set of names in the caption starting each code sample.

I'm very sorry for the inconvenience.)--Charlie O'Keefe

#32757: In the table of contents, the “Array” and similar sections are on the same level than the “Built-in Classes and Modules” section, thus, it is impossible to fold all built-in classes to show only the standard library classes.

The built-in classes should be a subsection of the “Built-in Classes and Modules” section.

Also, the naming in table of contents is somewhat strange, e.g. “Array” is named in the toc “4-1Array”.

In case something is unclear, you can mail me at giga@le-pec.org.

Thanks for your hard work.--Jean-Philippe Garcia Ballester

#35397: Hello Dave,

When describing Module.instance_methods you explain: "Returns an array containing the names of public instance methods in the receiver." It would be beneficial to point out _explicitly that this includes protected methods as well. I was just rereading and had to test it. :) A small note would have saved me some time.

wee% cat im.rb
module M
def pub; end

def pri; end

def pro; end

public :pub
protected :pro
private :pri
end

p M.instance_methods
wee% ruby -vw ./im.rb
ruby 1.8.7 (2008-08-11 patchlevel 72) [powerpc-darwin9.5.0]
["pro", "pub"]

--Emiel van de Laar

#35405: The second bullet point of the CSV description sounds like broken English, though I guess it is technically OK:

"Some CSV files have a header line. Read it, and then process the rest of the file. Auto-matically convert fields that look like numbers."

I think a little rewording would help there.

Also you are missing some fun of CSV tables on the next page. Try adding these lines to you examples:

p table[:count]
table[:in_stock] = [10, 5, 10, 10]
--James Edward Gray II

#30437: Chapter 28 (extending ruby) doesn't discuss the treading model in 1.9, and the big VM lock. I think this is a big change, and should be addressed, so people can write better extensions.

Excerpt from ko1:
See rb_thread_blocking_region() in thread.c.

rb_thread_blocking_region(
rb_blocking_function_t *func, void *data1,
rb_unblock_function_t *ubf, void *data2)

func() is your function which you want to do without GL. YARV
release GL and call func(). If func() returned, YARV acquire GL and
continue ruby program.

ubf (unblocking function) is called when another thread interrupts
this thread with Thread#kill, or main thread exits. You must set
ubf as interrupt function for func(). You must write ubf or ruby
will not exit until func() ends.--Victor Marius Costan

#35401: For the PDF version, please include a clickable A-Z list for the Index, as is done in the Rails PDF. I'm not sure what the proper PDF terminology for this is, but in the Preview app on Mac OS, it appears in the sidebar as an outline. The Rails PDF has "Symbols" and "A" through "Z" under "Index," whereas the Ruby PDF does not. It's very convenient. Thanks.

(Dave says: your mere wish is my command. I didn't bother creating a new release, but regenerate your existing PDF and the subentries will appear.)

#35444: Under "#" in the index, please add an entry pointing to the preface where you explain the Classname#methodname notation that you use. I remember when I was reading the previous edition, I kept running across this in the text but couldn't find the explanation of whether this was a legal Ruby method name or what. I only figured it out when I ran across almost by accident when looking at the preface some time later.