Errata for Programming Perl

"the perlthrtut manpage, which would have been approximately the same thing our �Threads� chapter would have been." This should read: "the perlthrtut manpage, which is approximately the same thing our �Threads� chapter would have been."

Note from the Author or Editor:
Change to read: "which is approximately the same thing as our".

The first sentence in the last paragraph references the wrong line number from the example program on page 19. It references line 15 when it should reference line 19.

Note from the Author or Editor:
Change as noted

End of Paragraph #3 ================ So now you can probably figure out that when we said: next LINE if $line =~ /^#/; we meant "Go to the next iteration of LINE loop if this line happens to begin with a # character." Discussion ========= The above paragraph text refers to an outdated code example (from the 3rd edition of this book). The text should be updated to reflect the latest code example on page 39.

Note from the Author or Editor:
Change the text to read: So now you can probably figure out that when we said: last LINE if $line =~ /^>/; we meant �Go to the last iteration of the LINE loop if this line happens to begin with a > character.�

The backtick example snippet at the top of the page says "perldoc $module", but the text two paragraphs below still says "The $user in our finger example above...", which refers to the example snippet given in the third edition.

Note from the Author or Editor:
Change as noted. Should read: "The $module in our perldoc example above..."

"File ages for -M, -A, and -C are returned in days (including fractional days) since the script started running." should be "File ages for -M, -A, and -C are returned in days (including fractional days) since modification/last access/inode change until the script started running."

Note from the Author or Editor:
Change "File ages for -M, -A, and -C are returned in days (including fractional days) since the script started running" to read "File ages for -M, -A, and -C are returned in days (including fractional days) respectively between the last file modification, access, or inode change time and when the script started running."

"The "Matches" column is not always an exact rendition." should be "The "Like" column is not always an exact rendition."

Note from the Author or Editor:
Change as noted. [status=fixed in the source]

"For simple strings or numbers, in becomes equivalent to this:" should be "For simple strings or numbers, it becomes equivalent to this:

Note from the Author or Editor:
Change as noted. [status=fixed in the source]

"True is exactly one of $a or $b is true, false otherwise" should be "True if exactly one of $a or $b is true, false otherwise"

Note from the Author or Editor:
Change as noted.

"it can be safely embedded within other expressions and functions calls" should be "it can be safely embedded within other expressions and function calls"

Note from the Author or Editor:
Change as noted.

The code examples each read a line from standard input. Because there is a trailing newline at the end of the input string, the output of the warn statement is split into 2 lines. Perhaps the code can be modified by chomping the input string so that the warn statement outputs a single line.

Note from the Author or Editor:
On page 134, above both lines that begin with �warn "unknown RGB...�, insert a new line at the same indentation level consisting entirely of chomp;

"given(EXPR) assign the value" should be "given(EXPR) assigns the value"

Note from the Author or Editor:
Change as noted.

The sentence reads, "But if EXPR2 does not get to use smartmatching, then the second argument will not get to either." I believe it should say EXPR1, not EXPR2.

Note from the Author or Editor:
Change as noted. Note that this sentence is in the 2nd paragraph, not the 3rd per the submitted location.

Some < and <= comparisons are missing a whitespace character. page 141: $i<= 10 page 141: $i<= 10 page 141: $i< 32 page 144: $i< @ary1 page 144: $j< @ary2 page 370: $y< 13 page 371: $x<= 8 page 371: $y<= 12 page 371: $x<= 8 page 464: $i< @string page 569: $i< 10 page 624: $i< 100 page 624: $i< 1000

Note from the Author or Editor:
Change all those to have a space right before the less-than symbol.

"because 255 might not be U+00FF LATIN SMALL LETTER Y (�) in the current locale" should be "because 255 might not be U+00FF LATIN SMALL LETTER Y WITH DIAERESIS (�) in the current locale"

Note from the Author or Editor:
Change as noted.

The sentence containing "the six translation escapes" should instead read "the seven translation escapes".

"Table 5-3" should be "Table 5-9" in the following sentence? An alphabetical list of these metasymbols can be found below in Table 5-3.

Note from the Author or Editor:
Change as noted

Unintended space following "\" in these table entries: \ NNN Yes Match the character given in octal, up to \377. \ n Yes Match nth capture group (decimal). and following "\c" in this table entry: \c X Yes Match the control character Control-X (\cZ, \c[, etc.).

Note from the Author or Editor:
Changed as noted.

"\o{NNNN} Yes Match the character give in octal." s/give/given/

Note from the Author or Editor:
Change as noted.

There's whitespace between ( and ":full", which seems unintentional.

Note from the Author or Editor:
Change as noted.

The phrase at the start of the second line of the second paragraph that reads "Unicode names sequence" should instead read "Unicode named sequence".

"That means a codepoint like U+0389, GREEK CAPITAL LETTER OMEGA, is always a \w character." should be "That means a codepoint like U+03A9, GREEK CAPITAL LETTER OMEGA, is always a \w character."

Note from the Author or Editor:
Change as noted.

"Joining punctuation an like underscore" should read "Joining punctuation like an underscore"

The entries under the last column, labelled Name, should be set in small capitals.

"The second column in Table 5-15 shows the POSIX classes available as of v5.14." s/second/first/

Note from the Author or Editor:
Change as noted.

The phrase in the table reading "occurring continuous ranges" should read "occurring in continuous ranges".

"the + quantifiers� repetitions" s/s'/'s/

Note from the Author or Editor:
Change as noted.

"the standard Tie:Hash::NamedCapture module" The first colon looks lonely. s/:/::/

Note from the Author or Editor:
Change as noted.

"Now access your named captures through those variables, just as you did with $+ and %+, but using your own names." should be "Now access your named captures through those variables, just as you did with %+ and %-, but using your own names."

Note from the Author or Editor:
Change as noted.

Delete the two words "other modifiers", because "modifiers" occurs after the list.

Change "six translation escapes" to "seven translation escapes".

Change "Table 5-3" to "Table 5-9".

Note from the Author or Editor:
Change as noted.

"patterns that were more than 10k longer" s/longer/long/ (or some other wording)

Note from the Author or Editor:
Change "more than 10k longer" to "over 10k in length".

I think the following refers to Table 5-9 instead of 5-3: A backslashed letter matches an abstract sequence, typically either a particular character or one of a set of characters, as listed in Table 5-3.

Note from the Author or Editor:
Change as noted

"When the Engine encounters (?<= PATTERN)" Superfluous space before PATTERN. The header doesn't have a space there, and neither do the similar sentences about (?=PATTERN) and (?!PATTERN). Same thing on page 249, 4th paragraph: "When the Engine encounters (?<! PATTERN)"

Note from the Author or Editor:
Change as noted.

Change "for left to right" to "from left to right".

Note from the Author or Editor:
Change as noted.

"Although (?> PATTERN) is useful" Superfluous space before PATTERN. (I searched for ' PATTERN)' in the PDF and didn't find any more.)

Note from the Author or Editor:
Change as noted.

Here's a list of straight quotes that should be curly quotes. I don't feel like flooding the errata list with separate submissions. word: pages it's: 252, 268, 713, 757, 805, 808, 810, 817, 868, 993, 1060 that's: 277 another's: 389 doesn't: 446 isn't: 655 programmer's: 675 you're: 759 he's: 904 here's: 1011 you'll: 1041

Note from the Author or Editor:
Change all the non-literals as noted.

The '#' on the following line: say "REGEX is $re\n"; # debugging output is not aligned with the others, and the \n should be dropped. (Compared to the 3rd edition, "print" has been changed to "say", but the \n and vertical alignment weren't updated to match.)

Note from the Author or Editor:
Change the say back to a print.

Assuming Perl v5.14, change "REGEX is (?i-xsm:" to "REGEX is (?^ui:".

Note from the Author or Editor:
Change as noted.

The phrase "pieces you that you've" looks incorrect in the following sentence (remove "you"?): So while you can use this technique to validate input, it has its points of frustration when it comes to pulling out the pieces you that you�ve just worked so hard to parse.

Note from the Author or Editor:
"pieces you that you've" should have the first "you" removed.

This sentence probably intends to refer to chapter 7: Now if you�re still wondering what those sub thingies are in the Tagger module, you�ll find out soon enough because that�s what Chapter 6 is all about.

Note from the Author or Editor:
Change as noted

The phrase "maintains a high level Perl compatibility" is missing the word "of" and so should read "maintains a high level of Perl compatibility".

Change "See 19." to "See Chapter 17."

In the following sentence, I think "seen" should be "see": Alas, you�ll even seen �text� files where some lines have one encoding but other lines have different encodings.

Note from the Author or Editor:
"you�ll even seen" should read "you�ll even see".

I cannot find a method by the name of "Filter_Value" in the DBM_Filter module documentation. I presume that the method "Filter_Value_Push" was meant to be used instead. Therefore the following change should be made: $dbobj->Filter_Value("utf8"); should be $dbobj->Filter_Value_Push("utf8");

Note from the Author or Editor:
Change as noted

Change "two string" to "two strings".

Note from the Author or Editor:
Change as noted

"That is, a single user-visible character (a grapheme) can require more than a single codepoint to represent." should be "That is, a single user-visible character (a grapheme) can require more than a single codepoint to represent it."

Note from the Author or Editor:
Change as noted

Change "LATIN LETTER SMALL O" to "LATIN SMALL LETTER O".

Note from the Author or Editor:
Change as noted

In the following sentence, I think it should read, "This may be what you want ...": This may be want you want in searching and related applications, but canonical decomposition normally works better than compatibility decomposition for most applications.

Note from the Author or Editor:
""This may be want you want" should read "This may be what you want".

Change "LATIN LETTER SMALL E WITH ACUTE" to "LATIN SMALL LETTER E WITH ACUTE".

Note from the Author or Editor:
Change as noted

Change "LATIN LETTER SMALL E" to "LATIN SMALL LETTER E".

Note from the Author or Editor:
Change as noted

There should be a comma between "combining characters" and "variation selectors".

"to know about more" should read "to know more about".

Change "\x{COMBINING TILDE}" to "\N{COMBINING TILDE}".

Note from the Author or Editor:
Change as noted

Change "strings comparisons" to "string comparisons".

Note from the Author or Editor:
Change as noted

Change "East_Asian_Width=Full" to "East_Asian_Width=Fullwidth".

Note from the Author or Editor:
Change per description.

"Rider", and "Riding" should go together should be "Rider" and "Riding" should go together

Note from the Author or Editor:
Change as noted

Change "differ" to "are the same" in the phrase "Only when primary strengths differ does it fall through to compare secondary strengths".

Note from the Author or Editor:
Change as noted.

Change "forwards compatibility" to "forward compatibility".

Note from the Author or Editor:
Change as noted

The following refers to Table 5-6, and I think it might be Table 5-12 instead (not sure): One thing to always be aware of is that, by default, the Perl shortcuts like \w, \s, and even \d match many Unicode characters based on particular character properties. These are described in Table 5-6, and are intended to match the formal definitions given in Annex C: Compatibility Properties from Unicode Technical Standard #18, �Unicode Regular Expressions�, version 13, from August 2008.

Note from the Author or Editor:
It should refer to table 5-11, not to 5-6.

Page 311 has the following sentence: It�s important to remember not to use �&� for the first set; that would be intersecting with nothing, resulting in an empty set. The preceding page (310) has this sentence: Intersection, specified with the �&" prefix, is useful for getting the common characters matched by two (or more) classes. The '�&�' on page 311 looks different from the '�&"' on page 310.

Note from the Author or Editor:
The ampersand should be a literal in "to remember not to use �&� for the first".

In the following table entries "mysin" ne "mysyn": sub mysin (_) mysyn $a mysyn

Note from the Author or Editor:
Both instances of "mysyn" should read "mysin".

In the following sentence, I think it meant to say, "an indirect filehandle": Anytime you have a variable that contains a filehandle instead of a bareword handle, you have an indirect filehandles.

Note from the Author or Editor:
Change as noted.

"Although you can usually use typeglob and references to typeglobs interchangeably, there are a few places where you can�t." The first "typeglob" should be in plural, too.

Note from the Author or Editor:
Change as noted.

print "Be ", red("careful"), "with that ", green("light"), "!!!"; s/"with/" with/

Note from the Author or Editor:
Change as noted.

In the following example, there is a semicolon (;) in front of "@_" that I don't think was intended: @colors = qw(red blue green yellow orange purple violet); for my $name (@colors) { no strict "refs"; # Allow symbolic references *$name = *{uc $name} = sub { "<FONT COLOR='$name'>;@_</FONT>" }; }

Note from the Author or Editor:
Change as noted.

"inside the print statement:" It's "say" now.

Note from the Author or Editor:
Change as noted.

"Some modules offer additional functionality in its import list." That should end with "in their import lists".

Note from the Author or Editor:
Change as noted.

The following sentence appears to be missing something (perhaps a word like "building" or "creating" or "defining" or ...?): Earlier, we said that there are two ways for a module: traditional or object-oriented.

Note from the Author or Editor:
Change "ways for a module" to "flavors of modules".

"CPAN:DistnameInfo" needs another colon.

Note from the Author or Editor:
Change as noted.

I think you meant, "Notice the lack of a comma ...": Notice the lack of a semicolon after the class name or instance:

Note from the Author or Editor:
Change as noted.

The text "has a similar problems" should read "has a similar problem".

The spurious ">" after Bombadil should be deleted.

There is a spurious paragraph break after "the result with make".

Not technically wrong, but "\015\12" usually appears as "\015\012": One additional consideration when writing Internet programs: many protocols specify that the line terminator should be CRLF, which can be specified various ways: "\r\n",11 "\015\12", or "\xd\xa", or even chr(13).chr(10). Many Internet programs will in fact accept a bare "\012" as a line terminator, but that�s because Internet programs usually try to be liberal in what they accept and strict in what they emit. (Now if only we could get people to do the same�)

Note from the Author or Editor:
Change "\015\12" to "\015\012", as noted

"Any value 0400 or above 0777 makes Perl slurp in whole files at once, but, by convention, the value 0777 is normally used for this." Should be: "Any value 0400 or above makes Perl slurp in whole files at once, but, by convention, the value 0777 is normally used for this."

Note from the Author or Editor:
Change as noted

There are two instances of curly quotes following -M that should be straight quotes.

Instead of "Other layers that5 would affect" it should read "Other layers that would affect".

Note from the Author or Editor:
Change as noted

I think you meant "is a sophisticated tool" or "is a sophisticated set of tools": Dist::Zilla Dist::Zilla is a sophisticated tools that does much more than merely create the initial distribution.

Note from the Author or Editor:
Change "tools" to "tool"

Did you mean "Encodings" because of "They"? Encoding cannot be guessed. They must be specified.

Note from the Author or Editor:
I'd rewrite this as "You cannot guess an encoding; you have to specify it."

I can't seem to find File::Mmap, e.g., https://metacpan.org/search?q=file%3A%3Ammap http://search.cpan.org/search?query=file%3A%3Ammap Use File::Mmap to read files if you don�t need to modify the data (and sometimes even if you do).

Note from the Author or Editor:
Change "File::Mmap" to "File::Map"

1) Granted that it depends on the pod translator, I still expected "touch -t" to appear in bold in this example. 2) Here and in many other places, both in the text and in examples, the hyphen appears as "�". Granted "�" B<looks> like an ascii hyphen, but if it's supposed to B<be> one, then it should be one. IMO. :�) Note that pod sequences do nest. That means you can write �The I<Santa MarE<iacute>a> left port already� to produce �The Santa Mar�a left port already�, or �B<touch> S<B<�t> I<time>> I<file>� to produce �touch �t time file�, and expect this to work properly.

Note from the Author or Editor:
The "touch" and the "-t" should be rendered in bold, but are currently italic.

This link goes to this address: http://www.stackoverflow.con/ Stackoverflow Stackoverflow is a question-and-answer site for general programming. Even though it is not dedicated to Perl, there are several Perl experts who frequent the site and answer questions.

Note from the Author or Editor:
Change "con" to "com" in the domain name.

Missing "$": $^S (EXCEPTIONS_BEING_CAUGHT)

Note from the Author or Editor:
Change as noted.

I may be making a stretch, but I don't think you meant, "each variable description in Table 25-1", because there aren't any variable descriptions in that table: So that we don�t have to keep repeating ourselves, each variable description in Table 25-1 starts with one or more of these annotations.

Note from the Author or Editor:
Delete "in Table 25.1"

This variable description is lacking an annotation, e.g., "[DYN]": $^N The text matched by the used group most-recently closed (i.e., the group with the rightmost closing parenthesis) of the last successful search pattern.

Note from the Author or Editor:
Prefix paragraph with "[DYN, RO]".

This variable description looks odd, as though there are two different versions of the description (each beginning with an "[ALL]"): %! [ALL] Each element of %! has a true value only if $! is set to that value. For example, $!{ENOENT} is true if and only if the current value of $! is ENOENT; that is, if the most recent error was �No such file or directory� (or its moral equivalent: not all operating systems, and certainly not all languages, give that exact error). To check for whether a particular key is meaningful on your system, use exists $!{SOMEKEY}; for a list of legal keys, use keys %!. See the documentation for the Errno module for more information, and see also $! above. This variable was added in v5.005. [ALL] This hash is defined only if you�ve loaded the standard Errno module. Once you�ve done this, you can subscript into %! using a particular error string, and its value is true only if that�s the current error. For example, $! [next page] {ENOENT} is true only if the C errno variable is currently set to the C #define value, ENOENT. This is convenient for accessing vendor-specific symbols.

Note from the Author or Editor:
Delete the second of the two paragraphs beginning with [ALL].

This variable description is lacking an annotation, e.g., "[DYN,RO]": ${^PREMATCH} This is just like $` ($PREMATCH) except that it does not incur the performance penalty associated with that variable, and it is only guaranteed to contain a defined value when the pattern was compiled or executed with the /p modifier.

Note from the Author or Editor:
Change as noted.

... q/, and nonzero binary with "0b"/ ... ? # Prefix nonzero octal with �0�, nonzero hex with �0x�

Note from the Author or Editor:
Add "nonzero binary with 0b" after "nonzero hex with 0x" in the fifth row in the table.

From the department of redundancy department: This also allows you to reuse arguments, too: printf '%2$d %1$d %2$d', 12, 34; # "34 12 34"

Note from the Author or Editor:
Remove ", too"

I can't seem to find a verb: The < and > for endianness on the specifier on d, D, f, F, i, I, j, J, l, L, p, P, q, Q, s, and S.

Note from the Author or Editor:
Change to "The < and > indicate the endianness for the specifiers d, ..."

More additional extra redundancy: The unpack function is also useful for plain text data, too, not just binary data.

Note from the Author or Editor:
Remove the ", too"

Are those last two paragraph repeats of the first two? If you fork without ever waiting on your children, you will accumulate zombies (exited processes whose parents haven�t waited on them yet). On some systems, you can avoid this by setting $SIG{CHLD} to �IGNORE�; on most, you must wait for your moribund children. See �wait� in this chapter for examples of doing this, or see the section �Signals� on page 518 in Chapter 15 for more on SIGCHLD. If a forked child inherits system file descriptors like STDIN and STDOUT that are connected to a remote pipe or socket, you may have to reopen these in the child [Perl Functions in Alphabetical Order | 865] to /dev/null. That�s because even when the parent process exits, the child will live on with its copies of those filehandles. The remote server (such as, say, a CGI script or a background job launched from a remote shell) will appear to hang because it�s still waiting for all copies to be closed. Reopening the system filehandles to something else fixes this. [...] If you fork without ever waiting on your children, you will accumulate zombies. On some systems, you can avoid this by setting $SIG{CHLD} to �IGNORE�. See also Chapter 15 for more examples of forking and reaping moribund children. Note that if your forked child inherits system file descriptors like STDIN and STDOUT that are actually connected by a pipe or socket, then the remote server (such as, say, a CGI script or a backgrounded job launched from a remote shell) won�t think you�re done, even if you exit the parent process. You should reopen those to /dev/null if this is an issue.

Note from the Author or Editor:
Delete the last two paragraphs of the fork section: they're duplicates.

Did you mean "The Socket module has a ...": The Socket module is a gethostinfo function that works for addresses in all common forms, including IPv6.

Note from the Author or Editor:
Change as noted

Did you mean "# 0 1 2": This function translates a protocol number to its corresponding name. The return value in list context is: # 1 2 3 ($name, $aliases, $protocol_number) = getprotobynumber(6);

Note from the Author or Editor:
Change as noted

Did you mean "# 0 1 2": These functions iterate through the /etc/protocols file. In list context, the return value from getprotoent is: # 1 2 3 ($name, $aliases, $protocol_number) = getprotoent();

Note from the Author or Editor:
It should be # 0 1 2 in both cases on this page

You mention 'use feature "fc"' in the 'lc' section (and the one for 'uc'), but not in the one for 'fc': Instead, use the fc (foldcase) function, either from the CPAN Unicode::CaseFold module, or via use feature "fc" in v5.16 or later.

Note from the Author or Editor:
Change the fc function on page 860 from reading simply "New to v5.16" to reading "New to v5.16 where it is enabled with C<use feature "fc">," � and of course set the C<> as a literal.

Did you mean something like this: $thisday = qw(Sun Mon Tue Wed Thu Fri Sat)[(localtime)[6]]; Don't get me wrong; I'm not the code police. It's just that it's been so long since I programmed with bare words, this looked like a syntax error: $thisday = (Sun,Mon,Tue,Wed,Thu,Fri,Sat)[(localtime)[6]];

Note from the Author or Editor:
Quote each word in the list for strict complacence.

The "use" in "use IPC::SysV" is different than where that phrase is used elsewhere (e.g., further down that page): This function calls the System V IPC msgget(2) syscall. See msgget(2) for details. The function returns the message queue ID, or undef if there is an error. Before calling, you should use IPC::SysV.

Note from the Author or Editor:
Set the "use" as a literal, like the other one.

I think you mean "$dec_perms" instead of "$perms": $dec_perms = (stat("filename"))[2] & 07777; $oct_perm_str = sprintf "%o", $perms;

Note from the Author or Editor:
Change $perms to $dec_perms

"To find the codepoint for a character gives it name as a string, use the charnames::vianame functions from the charnames pragma." should maybe be something like: "To find the codepoint for a character that gives its name as a string, use the charnames::vianame function from the charnames pragma."

Note from the Author or Editor:
It should read: "given its name as a string", and "functions" should be changed to "function".

The text states that the 'say' keyword: "...is available only when the "say" feature is enabled; see the section "Terms and List Operators (Leftward)" on page 97 in Chapter 3. This is an incorrect citation; this section is not relevant to enabling the "say" feature and does not refer to it at all. The correct citation would be to the section on the feature pragma on page 1017.

Note from the Author or Editor:
Change as noted

The sentence says, "print" but the example says, "say": Since a print function is a LIST operator, you have to say: say "Length is ", scalar(@ARRAY);

Note from the Author or Editor:
Change to "Since a say function is a LIST operator"

Did you mean "effects"? (Please don't hit me.) (A timeout of 0 affects a poll.)

Note from the Author or Editor:
Change "affects" back to "effects" per Camel3.

s/\.systems/systems/; One should probably not (attempt to) mix buffered I/O (like read or <HANDLE>) with select, except as permitted by POSIX, and even then only on truly POSIX .systems. Use sysread instead

Note from the Author or Editor:
The period at the front of the line should be its end.

The index references a unknown comparison operator: "cpm". Should have been "cmp".

Note from the Author or Editor:
Change as noted

Change : cdebugger ommand to debugger command. Also, change underPrint to undefPrint

Note from the Author or Editor:
Change as noted