perl5100delta.1

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

it's possible to do something like
.Sp
.Vb 3
\&    foreach my $name (keys %+) {
\&        print "content of buffer \*(Aq$name\*(Aq is $+{$name}\en";
\&    }
.Ve
.Sp
The \f(CW\*(C`%\-\*(C'\fR hash is a bit more complete, since it will contain array refs
holding values from all capture buffers similarly named, if there should
be many of them.
.Sp
\&\f(CW\*(C`%+\*(C'\fR and \f(CW\*(C`%\-\*(C'\fR are implemented as tied hashes through the new module
\&\f(CW\*(C`Tie::Hash::NamedCapture\*(C'\fR.
.Sp
Users exposed to the .NET regex engine will find that the perl
implementation differs in that the numerical ordering of the buffers
is sequential, and not \*(L"unnamed first, then named\*(R". Thus in the pattern
.Sp
.Vb 1
\&   /(A)(?<B>B)(C)(?<D>D)/
.Ve
.Sp
\&\f(CW$1\fR will be 'A', \f(CW$2\fR will be 'B', \f(CW$3\fR will be 'C' and \f(CW$4\fR will be 'D' and not
\&\f(CW$1\fR is 'A', \f(CW$2\fR is 'C' and \f(CW$3\fR is 'B' and \f(CW$4\fR is 'D' that a .NET programmer
would expect. This is considered a feature. :\-) (Yves Orton)
.IP "Possessive Quantifiers" 4
.IX Item "Possessive Quantifiers"
Perl now supports the \*(L"possessive quantifier\*(R" syntax of the \*(L"atomic match\*(R"
pattern. Basically a possessive quantifier matches as much as it can and never
gives any back. Thus it can be used to control backtracking. The syntax is
similar to non-greedy matching, except instead of using a '?' as the modifier
the '+' is used. Thus \f(CW\*(C`?+\*(C'\fR, \f(CW\*(C`*+\*(C'\fR, \f(CW\*(C`++\*(C'\fR, \f(CW\*(C`{min,max}+\*(C'\fR are now legal
quantifiers. (Yves Orton)
.IP "Backtracking control verbs" 4
.IX Item "Backtracking control verbs"
The regex engine now supports a number of special-purpose backtrack
control verbs: (*THEN), (*PRUNE), (*MARK), (*SKIP), (*COMMIT), (*FAIL)
and (*ACCEPT). See perlre for their descriptions. (Yves Orton)
.IP "Relative backreferences" 4
.IX Item "Relative backreferences"
A new syntax \f(CW\*(C`\eg{N}\*(C'\fR or \f(CW\*(C`\egN\*(C'\fR where \*(L"N\*(R" is a decimal integer allows a
safer form of back-reference notation as well as allowing relative
backreferences. This should make it easier to generate and embed patterns
that contain backreferences. See \*(L"Capture buffers\*(R" in perlre. (Yves Orton)
.ie n .IP """\eK"" escape" 4
.el .IP "\f(CW\eK\fR escape" 4
.IX Item "K escape"
The functionality of Jeff Pinyan's module Regexp::Keep has been added to
the core. In regular expressions you can now use the special escape \f(CW\*(C`\eK\*(C'\fR
as a way to do something like floating length positive lookbehind. It is
also useful in substitutions like:
.Sp
.Vb 1
\&  s/(foo)bar/$1/g
.Ve
.Sp
that can now be converted to
.Sp
.Vb 1
\&  s/foo\eKbar//g
.Ve
.Sp
which is much more efficient. (Yves Orton)
.IP "Vertical and horizontal whitespace, and linebreak" 4
.IX Item "Vertical and horizontal whitespace, and linebreak"
Regular expressions now recognize the \f(CW\*(C`\ev\*(C'\fR and \f(CW\*(C`\eh\*(C'\fR escapes that match
vertical and horizontal whitespace, respectively. \f(CW\*(C`\eV\*(C'\fR and \f(CW\*(C`\eH\*(C'\fR
logically match their complements.
.Sp
\&\f(CW\*(C`\eR\*(C'\fR matches a generic linebreak, that is, vertical whitespace, plus
the multi-character sequence \f(CW"\ex0D\ex0A"\fR.
.ie n .Sh """say()"""
.el .Sh "\f(CWsay()\fP"
.IX Subsection "say()"
\&\fIsay()\fR is a new built-in, only available when \f(CW\*(C`use feature \*(Aqsay\*(Aq\*(C'\fR is in
effect, that is similar to \fIprint()\fR, but that implicitly appends a newline
to the printed string. See \*(L"say\*(R" in perlfunc. (Robin Houston)
.ie n .Sh "Lexical $_"
.el .Sh "Lexical \f(CW$_\fP"
.IX Subsection "Lexical $_"
The default variable \f(CW$_\fR can now be lexicalized, by declaring it like
any other lexical variable, with a simple
.PP
.Vb 1
\&    my $_;
.Ve
.PP
The operations that default on \f(CW$_\fR will use the lexically-scoped
version of \f(CW$_\fR when it exists, instead of the global \f(CW$_\fR.
.PP
In a \f(CW\*(C`map\*(C'\fR or a \f(CW\*(C`grep\*(C'\fR block, if \f(CW$_\fR was previously my'ed, then the
\&\f(CW$_\fR inside the block is lexical as well (and scoped to the block).
.PP
In a scope where \f(CW$_\fR has been lexicalized, you can still have access to
the global version of \f(CW$_\fR by using \f(CW$::_\fR, or, more simply, by
overriding the lexical declaration with \f(CW\*(C`our $_\*(C'\fR. (Rafael Garcia-Suarez)
.ie n .Sh "The ""_"" prototype"
.el .Sh "The \f(CW_\fP prototype"
.IX Subsection "The _ prototype"
A new prototype character has been added. \f(CW\*(C`_\*(C'\fR is equivalent to \f(CW\*(C`$\*(C'\fR but
defaults to \f(CW$_\fR if the corresponding argument isn't supplied. (both \f(CW\*(C`$\*(C'\fR
and \f(CW\*(C`_\*(C'\fR denote a scalar). Due to the optional nature of the argument, you
can only use it at the end of a prototype, or before a semicolon.
.PP
This has a small incompatible consequence: the \fIprototype()\fR function has
been adjusted to return \f(CW\*(C`_\*(C'\fR for some built-ins in appropriate cases (for
example, \f(CW\*(C`prototype(\*(AqCORE::rmdir\*(Aq)\*(C'\fR). (Rafael Garcia-Suarez)
.Sh "\s-1UNITCHECK\s0 blocks"
.IX Subsection "UNITCHECK blocks"
\&\f(CW\*(C`UNITCHECK\*(C'\fR, a new special code block has been introduced, in addition to
\&\f(CW\*(C`BEGIN\*(C'\fR, \f(CW\*(C`CHECK\*(C'\fR, \f(CW\*(C`INIT\*(C'\fR and \f(CW\*(C`END\*(C'\fR.
.PP
\&\f(CW\*(C`CHECK\*(C'\fR and \f(CW\*(C`INIT\*(C'\fR blocks, while useful for some specialized purposes,
are always executed at the transition between the compilation and the
execution of the main program, and thus are useless whenever code is
loaded at runtime. On the other hand, \f(CW\*(C`UNITCHECK\*(C'\fR blocks are executed
just after the unit which defined them has been compiled. See perlmod
for more information. (Alex Gough)
.ie n .Sh "New Pragma, ""mro"""
.el .Sh "New Pragma, \f(CWmro\fP"
.IX Subsection "New Pragma, mro"
A new pragma, \f(CW\*(C`mro\*(C'\fR (for Method Resolution Order) has been added. It
permits to switch, on a per-class basis, the algorithm that perl uses to
find inherited methods in case of a multiple inheritance hierarchy. The
default \s-1MRO\s0 hasn't changed (\s-1DFS\s0, for Depth First Search). Another \s-1MRO\s0 is
available: the C3 algorithm. See mro for more information.
(Brandon Black)
.PP
Note that, due to changes in the implementation of class hierarchy search,
code that used to undef the \f(CW*ISA\fR glob will most probably break. Anyway,
undef'ing \f(CW*ISA\fR had the side-effect of removing the magic on the \f(CW@ISA\fR
array and should not have been done in the first place. Also, the
cache \f(CW*::ISA::CACHE::\fR no longer exists; to force reset the \f(CW@ISA\fR cache,
you now need to use the \f(CW\*(C`mro\*(C'\fR \s-1API\s0, or more simply to assign to \f(CW@ISA\fR
(e.g. with \f(CW\*(C`@ISA = @ISA\*(C'\fR).
.ie n .Sh "\fIreaddir()\fP may return a ""short filename"" on Windows"
.el .Sh "\fIreaddir()\fP may return a ``short filename'' on Windows"
.IX Subsection "readdir() may return a short filename on Windows"
The \fIreaddir()\fR function may return a \*(L"short filename\*(R" when the long
filename contains characters outside the \s-1ANSI\s0 codepage.  Similarly
\&\fICwd::cwd()\fR may return a short directory name, and \fIglob()\fR may return short
names as well.  On the \s-1NTFS\s0 file system these short names can always be
represented in the \s-1ANSI\s0 codepage.  This will not be true for all other file
system drivers; e.g. the \s-1FAT\s0 filesystem stores short filenames in the \s-1OEM\s0
codepage, so some files on \s-1FAT\s0 volumes remain unaccessible through the
\&\s-1ANSI\s0 APIs.
.PP
Similarly, $^X, \f(CW@INC\fR, and \f(CW$ENV\fR{\s-1PATH\s0} are preprocessed at startup to make
sure all paths are valid in the \s-1ANSI\s0 codepage (if possible).
.PP
The \fIWin32::GetLongPathName()\fR function now returns the \s-1UTF\-8\s0 encoded
correct long file name instead of using replacement characters to force
the name into the \s-1ANSI\s0 codepage.  The new \fIWin32::GetANSIPathName()\fR
function can be used to turn a long pathname into a short one only if the
long one cannot be represented in the \s-1ANSI\s0 codepage.
.PP
Many other functions in the \f(CW\*(C`Win32\*(C'\fR module have been improved to accept
\&\s-1UTF\-8\s0 encoded arguments.  Please see Win32 for details.
.Sh "\fIreadpipe()\fP is now overridable"
.IX Subsection "readpipe() is now overridable"
The built-in function \fIreadpipe()\fR is now overridable. Overriding it permits
also to override its operator counterpart, \f(CW\*(C`qx//\*(C'\fR (a.k.a. \f(CW\*(C`\`\`\*(C'\fR).
Moreover, it now defaults to \f(CW$_\fR if no argument is provided. (Rafael
Garcia-Suarez)
.Sh "Default argument for \fIreadline()\fP"
.IX Subsection "Default argument for readline()"
\&\fIreadline()\fR now defaults to \f(CW*ARGV\fR if no argument is provided. (Rafael
Garcia-Suarez)
.Sh "\fIstate()\fP variables"
.IX Subsection "state() variables"
A new class of variables has been introduced. State variables are similar
to \f(CW\*(C`my\*(C'\fR variables, but are declared with the \f(CW\*(C`state\*(C'\fR keyword in place of
\&\f(CW\*(C`my\*(C'\fR. They're visible only in their lexical scope, but their value is
persistent: unlike \f(CW\*(C`my\*(C'\fR variables, they're not undefined at scope entry,
but retain their previous value. (Rafael Garcia-Suarez, Nicholas Clark)
.PP
To use state variables, one needs to enable them by using
.PP
.Vb 1
\&    use feature \*(Aqstate\*(Aq;
.Ve
.PP
or by using the \f(CW\*(C`\-E\*(C'\fR command-line switch in one-liners.
See \*(L"Persistent variables via \fIstate()\fR\*(R" in perlsub.
.Sh "Stacked filetest operators"
.IX Subsection "Stacked filetest operators"
As a new form of syntactic sugar, it's now possible to stack up filetest
operators. You can now write \f(CW\*(C`\-f \-w \-x $file\*(C'\fR in a row to mean
\&\f(CW\*(C`\-x $file && \-w _ && \-f _\*(C'\fR. See \*(L"\-X\*(R" in perlfunc.
.Sh "\s-1\fIUNIVERSAL::DOES\s0()\fP"
.IX Subsection "UNIVERSAL::DOES()"
The \f(CW\*(C`UNIVERSAL\*(C'\fR class has a new method, \f(CW\*(C`DOES()\*(C'\fR. It has been added to
solve semantic problems with the \f(CW\*(C`isa()\*(C'\fR method. \f(CW\*(C`isa()\*(C'\fR checks for
inheritance, while \f(CW\*(C`DOES()\*(C'\fR has been designed to be overridden when
module authors use other types of relations between classes (in addition
to inheritance). (chromatic)
.PP
See \*(L"$obj\->\s-1DOES\s0( \s-1ROLE\s0 )\*(R" in \s-1UNIVERSAL\s0.
.Sh "Formats"
.IX Subsection "Formats"
Formats were improved in several ways. A new field, \f(CW\*(C`^*\*(C'\fR, can be used for
variable-width, one-line-at-a-time text. Null characters are now handled
correctly in picture lines. Using \f(CW\*(C`@#\*(C'\fR and \f(CW\*(C`~~\*(C'\fR together will now
produce a compile-time error, as those format fields are incompatible.
perlform has been improved, and miscellaneous bugs fixed.
.Sh "Byte-order modifiers for \fIpack()\fP and \fIunpack()\fP"
.IX Subsection "Byte-order modifiers for pack() and unpack()"
There are two new byte-order modifiers, \f(CW\*(C`>\*(C'\fR (big-endian) and \f(CW\*(C`<\*(C'\fR
(little-endian), that can be appended to most \fIpack()\fR and \fIunpack()\fR template
characters and groups to force a certain byte-order for that type or group.
See \*(L"pack\*(R" in perlfunc and perlpacktut for details.
.ie n .Sh """no VERSION"""
.el .Sh "\f(CWno VERSION\fP"
.IX Subsection "no VERSION"
You can now use \f(CW\*(C`no\*(C'\fR followed by a version number to specify that you
want to use a version of perl older than the specified one.
.ie n .Sh """chdir""\fP, \f(CW""chmod""\fP and \f(CW""chown"" on filehandles"
.el .Sh "\f(CWchdir\fP, \f(CWchmod\fP and \f(CWchown\fP on filehandles"
.IX Subsection "chdir, chmod and chown on filehandles"
\&\f(CW\*(C`chdir\*(C'\fR, \f(CW\*(C`chmod\*(C'\fR and \f(CW\*(C`chown\*(C'\fR can now work on filehandles as well as
filenames, if the system supports respectively \f(CW\*(C`fchdir\*(C'\fR, \f(CW\*(C`fchmod\*(C'\fR and
\&\f(CW\*(C`fchown\*(C'\fR, thanks to a patch provided by Gisle Aas.
.Sh "\s-1OS\s0 groups"
.IX Subsection "OS groups"
\&\f(CW$(\fR and \f(CW$)\fR now return groups in the order where the \s-1OS\s0 returns them,
thanks to Gisle Aas. This wasn't previously the case.
.Sh "Recursive sort subs"
.IX Subsection "Recursive sort subs"
You can now use recursive subroutines with \fIsort()\fR, thanks to Robin Houston.
.Sh "Exceptions in constant folding"
.IX Subsection "Exceptions in constant folding"
The constant folding routine is now wrapped in an exception handler, and
if folding throws an exception (such as attempting to evaluate 0/0), perl
now retains the current optree, rather than aborting the whole program.
Without this change, programs would not compile if they had expressions that
happened to generate exceptions, even though those expressions were in code
that could never be reached at runtime. (Nicholas Clark, Dave Mitchell)
.ie n .Sh "Source filters in @INC"
.el .Sh "Source filters in \f(CW@INC\fP"
.IX Subsection "Source filters in @INC"
It's possible to enhance the mechanism of subroutine hooks in \f(CW@INC\fR by
adding a source filter on top of the filehandle opened and returned by the
hook. This feature was planned a long time ago, but wasn't quite working
until now. See \*(L"require\*(R" in perlfunc for details. (Nicholas Clark)
.Sh "New internal variables"
.IX Subsection "New internal variables"
.ie n .IP """${^RE_DEBUG_FLAGS}""" 4
.el .IP "\f(CW${^RE_DEBUG_FLAGS}\fR" 4
.IX Item "${^RE_DEBUG_FLAGS}"
This variable controls what debug flags are in effect for the regular
expression engine when running under \f(CW\*(C`use re "debug"\*(C'\fR. See re for
details.
.ie n .IP """${^CHILD_ERROR_NATIVE}""" 4
.el .IP "\f(CW${^CHILD_ERROR_NATIVE}\fR" 4
.IX Item "${^CHILD_ERROR_NATIVE}"
This variable gives the native status returned by the last pipe close,
backtick command, successful call to \fIwait()\fR or \fIwaitpid()\fR, or from the
\&\fIsystem()\fR operator. See perlrun for details. (Contributed by Gisle Aas.)
.ie n .IP """${^RE_TRIE_MAXBUF}""" 4
.el .IP "\f(CW${^RE_TRIE_MAXBUF}\fR" 4
.IX Item "${^RE_TRIE_MAXBUF}"
See \*(L"Trie optimisation of literal string alternations\*(R".
.ie n .IP """${^WIN32_SLOPPY_STAT}""" 4
.el .IP "\f(CW${^WIN32_SLOPPY_STAT}\fR" 4
.IX Item "${^WIN32_SLOPPY_STAT}"
See \*(L"Sloppy stat on Windows\*(R".
.Sh "Miscellaneous"
.IX Subsection "Miscellaneous"
\&\f(CW\*(C`unpack()\*(C'\fR now defaults to unpacking the \f(CW$_\fR variable.
.PP
\&\f(CW\*(C`mkdir()\*(C'\fR without arguments now defaults to \f(CW$_\fR.
.PP
The internal dump output has been improved, so that non-printable characters
such as newline and backspace are output in \f(CW\*(C`\ex\*(C'\fR notation, rather than