-New regexp routines derived from Henry Spencer's.
- Support for /(foo|bar)/.
- Support for /(foo)*/ and /(foo)+/.
- \s for whitespace, \S nonwhitespace
- \d for digit, \D nondigit
+Changes to perl
+---------------
-Local variables in blocks, subroutines and evals.
+Apart from little bug fixes, here are the new features:
-Recursive subroutine calls are now supported.
+Perl can now handle binary data correctly and has functions to pack and
+unpack binary structures into arrays or lists. You can now do arbitrary
+ioctl functions.
-Array values may now be interpolated into lists:
- unlink 'foo', 'bar', @trashcan, 'tmp';
+You can do i/o with sockets and select.
-File globbing via <*.foo>.
+You can now write packages with their own namespace.
-Use of <> in array contexts returns the whole file or glob list:
- unlink <*.foo>;
+You can now pass things to subroutines by reference.
-New iterator for normal arrays, foreach, that allows both read and write:
- foreach $elem ($array) {
- $elem =~ s/foo/bar/;
- }
+The debugger now has hooks in the perl parser so it doesn't get confused.
+The debugger won't interfere with stdin and stdout. New debugger commands:
+ n Single step around subroutine call.
+ l min+incr List incr+1 lines starting at min.
+ l List incr+1 more lines.
+ l subname List subroutine.
+ b subname Set breakpoint at first line of subroutine.
+ S List subroutine names.
+ D Delete all breakpoints.
+ A List line actions.
+ < command Define command before prompt.
+ > command Define command after prompt.
+ ! number Redo command (default previous command).
+ ! -number Redo numberth to last command.
+ h -number Display last number commands (default all).
+ p expr Same as \"print DBout expr\".
-Ability to open pipe to a forked off script for secure pipes in setuid scripts.
+The rules are more consistent about where parens are needed and
+where they are not. In particular, unary operators and list operators now
+behave like functions if they're called like functions.
-File inclusion via
- do 'foo.pl';
+There are some new quoting mechanisms:
+ $foo = q/"'"'"'"'"'"'"/;
+ $foo = qq/"'"''$bar"''/;
+ $foo = q(hi there);
+ $foo = <<'EOF' x 10;
+ Why, it's the old here-is mechanism!
+ EOF
-More file tests, including -t to see if, for instance, stdin is
-a terminal. File tests now behave in a more correct manner. You can do
-file tests on filehandles as well as filenames. The special filetests
--T and -B test a file to see if it's text or binary.
+You can now work with array slices (note the initial @):
+ @foo[1,2,3];
+ @foo{'Sun','Mon','Tue','Wed','Thu','Fri','Sat'} = (1,2,3,4,5,6,7);
+ @foo{split} = (1,1,1,1,1,1,1);
-An eof can now be used on each file of the <> input for such purposes
-as resetting the line numbers or appending to each file of an inplace edit.
+There's now a range operator that works in array contexts:
+ for (1..15) { ...
+ @foo[3..5] = ('time','for','all');
+ @foo{'Sun','Mon','Tue','Wed','Thu','Fri','Sat'} = 1..7;
-Assignments can now function as lvalues, so you can say things like
- ($HOST = $host) =~ tr/a-z/A-Z/;
- ($obj = $src) =~ s/\.c$/.o/;
+You can now reference associative arrays as a whole:
+ %abc = %def;
+ %foo = ('Sun',1,'Mon',2,'Tue',3,'Wed',4,'Thu',5,'Fri',6,'Sat',7);
-You can now do certain file operations with a variable which holds the name
-of a filehandle, e.g. open(++$incl,$includefilename); $foo = <$incl>;
+Associative arrays can now be bound to a dbm or ndbm file. Perl automatically
+caches references to the dbm file for you.
-You can now a subroutine indirectly through a scalar variable:
- $which = 'xyz';
- do $which('foo'); # calls xyz
+An array or associative array can now be assigned to as part of a list, if
+it's the last thing in the list:
+ ($a,$b,@rest) = split;
-Warnings are now available (with -w) on use of uninitialized variables and on
-identifiers that are mentioned only once, and on reference to various
-undefined things.
+An array or associative array may now appear in a local() list.
+ local(%assoc);
+ local(@foo) = @_;
-The -S switch causes perl to search the PATH for the script so that you can say
- eval "exec /usr/bin/perl -S $0 $*"
- if $running_under_some_shell;
+Array values may now be interpolated into strings:
+ `echo @ARGV`;
+ print "first three = @list[0..2]\n";
+ print "@ENV{keys(ENV)}";
+ ($" is used as the delimiter between array elements)
-Reset now resets arrays and associative arrays as well as string variables.
+Array sizes may be interpolated into strings:
+ print "The last element is $#foo.\n";
-Assigning off the end of an array now nulls out any intervening values.
+Array values may now be returned from subroutines, evals, and do blocks.
-$#foo is now an lvalue. You can preallocate or truncate arrays, or recover
-values lost to prior truncation.
+Lists of values in formats may now be arbitrary expressions, separated
+by commas.
-$#foo is now indexed to $[ properly.
+Subroutine names are now distinguished by prefixing with &. You can call
+subroutines without using do, and without passing any argument list at all:
+ $foo = &min($a,$b,$c);
+ $num = &myrand;
-s/foo/bar/i optimization bug fixed.
+You can use the new -u switch to cause perl to dump core so that you can
+run undump and produce a binary executable image. Alternately you can
+use the "dump" operator after initializing any variables and such.
-The $x = "...$x..."; bug is fixed.
+Perl now optimizes splits that are assigned directly to an array, or
+to a list with fewer elements than the split would produce, or that
+split on a constant string.
-The @ary = (1); bug is now fixed. You can even say @ary = 1;
+Perl now optimizes on end matches such as /foo$/;
-$= now returns the correct value.
+Perl now recognizes {n,m} in patterns to match preceding item at least n times
+and no more than m times. Also recognizes {n,} and {n} to match n or more
+times, or exactly n times. If { occurs in other than this context it is
+still treated as a normal character.
-Several of the larger files are now split into smaller pieces for easier
-compilation.
+Perl now optimizes "next" to avoid unnecessary longjmps and subroutine calls.
-Pattern matches evaluated in an array context now return ($1, $2...).
+Perl now optimizes appended input: $_ .= <>;
-There is now a wait operator.
+Substitutions are faster if the substituted text is constant, especially
+when substituting at the beginning of a string. This plus the previous
+optimization let you run down a file comparing multiple lines more
+efficiently. (Basically the equivalents of sed's N and D are faster.)
-There is now a sort operator.
+Similarly, combinations of shifts and pushes on the same array are much
+faster now--it doesn't copy all the pointers every time you shift (just
+every n times, where n is approximately the length of the array plus 10,
+more if you pre-extend the array), so you can use an array as a shift
+register much more efficiently:
+ push(@ary,shift(@ary));
+or
+ shift(@ary); push(@ary,<>);
-The requirement of parens around certain expressions when taking their value
-has been lifted. In particular, you can say
- $x = print "foo","bar";
- $x = unlink "foo","bar";
- chdir "foo" || die "Can't chdir to foo\n";
+The shift operator used inside subroutines now defaults to shifting
+the @_ array. You can still shift ARGV explicitly, of course.
+
+The @_ array which is passed to subroutines is a local array, but the
+elements of it are passed by reference now. This means that if you
+explicitly modify $_[0], you are actually modifying the first argument
+to the routine. Assignment to another location (such as the usual
+local($foo) = @_ trick) causes a copy of the value, so this will not
+affect most scripts. However, if you've modified @_ values in the
+subroutine you could be in for a surprise. I don't believe most people
+will find this a problem, and the long term efficiency gain is worth
+a little confusion.
+
+Perl now detects sequences of references to the same variable and builds
+switch statements internally wherever reasonable.
+
+The substr function can take offsets from the end of the string.
+
+The substr function can be assigned to in order to change the interior of a
+string in place.
+
+The split function can return as part of the returned array any substrings
+matched as part of the delimiter:
+ split(/([-,])/, '1-10,20')
+returns
+ (1,'-',10,',',20)
+
+If you specify a maximum number of fields to split, the truncation of
+trailing null fields is disabled.
+
+You can now chop lists.
+
+Perl now uses /bin/csh to do filename globbing, if available. This means
+that filenames with spaces or other strangenesses work right.
+
+Perl can now report multiple syntax errors with a single invocation.
+
+Perl syntax errors now give two tokens of context where reasonable.
+
+Perl will now report the possibility of a runaway multi-line string if
+such a string ends on a line with a syntax error.
+
+The assumed assignment in a while now works in the while modifier as
+well as the while statement.
+
+Perl can now warn you if you use numeric == on non-numeric string values.
+
+New functions:
+ mkdir and rmdir
+ getppid
+ getpgrp and setpgrp
+ getpriority and setpriority
+ chroot
+ ioctl and fcntl
+ flock
+ readlink
+ lstat
+ rindex - find last occurrence of substring
+ pack and unpack - turn structures into arrays and vice versa
+ read - just what you think
+ warn - like die, only not fatal
+ dbmopen and dbmclose - bind a dbm file to an associative array
+ dump - do core dump so you can undump
+ reverse - turns an array value end for end
+ defined - does an object exist?
+ undef - make an object not exist
+ vec - treat string as a vector of small integers
+ fileno - return the file descriptor for a handle
+ wantarray - was subroutine called in array context?
+ opendir
+ readdir
+ telldir
+ seekdir
+ rewinddir
+ closedir
+ syscall
+ socket
+ bind
+ connect
+ listen
+ accept
+ shutdown
+ socketpair
+ getsockname
+ getpeername
+ getsockopt
+ setsockopt
+ getpwnam
+ getpwuid
+ getpwent
+ setpwent
+ endpwent
+ getgrnam
+ getgrgid
+ getgrent
+ setgrent
+ endgrent
+ gethostbyname
+ gethostbyaddr
+ gethostent
+ sethostent
+ endhostent
+ getnetbyname
+ getnetbyaddr
+ getnetent
+ setnetent
+ endnetent
+ getprotobyname
+ getprotobynumber
+ getprotoent
+ setprotoent
+ endprotoent
+ getservbyname
+ getservbyport
+ getservent
+ setservent
+ endservent
+
+Changes to s2p
+--------------
+
+In patterns, s2p now translates \{n,m\} correctly to {n,m}.
+
+In patterns, s2p no longer removes backslashes in front of |.
+
+In patterns, s2p now removes backslashes in front of [a-zA-Z0-9].
+
+S2p now makes use of the location of perl as determined by Configure.
+
+
+Changes to a2p
+--------------
+
+A2p can now accurately translate the "in" operator by using perl's new
+"defined" operator.
+
+A2p can now accurately translate the passing of arrays by reference.
-The manual is now not lying when it says that perl is generally faster than
-sed. I hope.
https://perl5.git.perl.org / perl5.git / blobdiff