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![Ouch!
$ perl some_script.pl
Out of memory!
$
$ perl some_script.pl
Killed.
$
$ perl some_script.pl
$
Someone shouts: "Hey! My process has been killed!"
$ perl some_script.pl
[...later...] "Umm, what's taking so long?"](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-22-2048.jpg)
![$ perl -e 'system("cat /proc/$$/maps")'
address perms ... pathname
00400000-00401000 r-xp ... /.../perl-5.NN.N/bin/perl
00601000-00602000 rw-p ... /.../perl-5.NN.N/bin/perl
0087f000-008c1000 rw-p ... [heap]
7f858cba1000-7f8592a32000 r--p ... /usr/lib/locale/locale-archive-rpm
7f8592c94000-7f8592e1a000 r-xp ... /lib64/libc-2.12.so
7f8592e1a000-7f859301a000 ---p ... /lib64/libc-2.12.so
7f859301a000-7f859301e000 r--p ... /lib64/libc-2.12.so
7f859301e000-7f859301f000 rw-p ... /lib64/libc-2.12.so
7f859301f000-7f8593024000 rw-p ...
...other libs...
7f8593d1b000-7f8593e7c000 r-xp ... /.../lib/5.NN.N/x86_64-linux/CORE/libperl.so
7f8593e7c000-7f859407c000 ---p ... /.../lib/5.NN.N/x86_64-linux/CORE/libperl.so
7f859407c000-7f8594085000 rw-p ... /.../lib/5.NN.N/x86_64-linux/CORE/libperl.so
7f85942a6000-7f85942a7000 rw-p ...
7fff61284000-7fff6129a000 rw-p ... [stack]
7fff613fe000-7fff61400000 r-xp ... [vdso]
ffffffffff600000-ffffffffff601000 r-xp ... [vsyscall]](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-26-2048.jpg)
![Devel::Size
• Gives you a measure of the size of a data structure
$ perl -MDevel::Size=total_size -le 'print total_size( 0 )'
24
$ perl -MDevel::Size=total_size -le 'print total_size( [] )'
64
$ perl -MDevel::Size=total_size -le 'print total_size( {} )'
120
$ perl -MDevel::Size=total_size -le 'print total_size( [ 1..100 ] )'
3264
• Is very fast, and accurate for most simple data types.
• Has limitations and bugs, but is the best tool we have.](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-37-2048.jpg)
![Space in Hiding
✦ Perl tends to consume extra memory to save time
✦ This can lead to surprises, for example:
✦ sub foo {
my $var = "X" x 10_000_000;
}
foo(); # ~20MB still used after return!
✦ sub bar{
my $var = "X" x 10_000_000;
bar($_[0]-1) if $_[0]; # recurse
}
bar(50); # ~1GB still used after return!](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-40-2048.jpg)
![Series and Reduction
‣ say 1, 2, 4 ... 1024;
1 2 4 8 16 32 64 128 256 512 1024
‣ my @fib = 1, 1, *+* ... *; # infinite
say @fib[^10]; # 0..9
1 1 2 3 5 8 13 21 34 55 89
‣ say [*] 1..10; # reduction, use any operator
3628800
‣ sub postfix:<!>($n) { [*] 1..$n }
say 10!
3628800](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-68-2048.jpg)
![Multiple Dispatch
‣ multi fact(0) { 1 }
multi fact($n) { $n * fact($n – 1) }
‣ multi fib(0) { 0 }
multi fib(1) { 1 }
multi fib($n) { fib($n – 1) + fib($n – 2) }
‣ multi quicksort([]) { () }
multi quicksort([$pivot, *@rest]) {
my @before = @rest.grep(* < $pivot);
my @after = @rest.grep(* >= $pivot);
(quicksort(@before), $pivot, quicksort(@after))
}](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-69-2048.jpg)
![Native Call Interface
sub PQexecPrepared(
- OpaquePointer $conn,
Str $statement_name,
Int $n_params,
CArray[Str] $param_values,
CArray[int] $param_length,
CArray[int] $param_formats,
Int $resultFormat)
- returns OpaquePointer
is native('libpq')
{ ... }
Also supports structures and callbacks.](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-70-2048.jpg)
![my @suits = < ♣ ♢ ♡ ♠ >;
my @ranks = 2..10, < J Q K A >;
# concatenate each rank with each suit
my @deck = @ranks X~ @suits;
# create hash of card to points value
my %points = @deck Z ( (2..10, 10, 10, 10, 11)
X+ (0,0,0,0) );
# grab five cards from the deck
my @hand = @deck.pick(5);
# display my hand
say ~@hand;
# tell me how many points it's worth
say [+] %points{@hand};](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-71-2048.jpg)
![@xyz»++ # increment all elements of @xyz
@x = @a »min« @b # @x is smallest of @a and @b
$mean = ([+] @a) / @a # calculate mean of @a
$sumsq = [+] (@x »**» 2) # sum of squares of @x
$fact = [*] 1..$n # $n factorial
for %hash.kv -> $k, $v { say "$k: $v" }](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-72-2048.jpg)
![module JSON::Tiny;
proto to-json($) is export {*}
multi to-json(Real:D $d) { ~$d }
multi to-json(Bool:D $d) { $d ?? 'true' !! 'false'; }
multi to-json(Str:D $d) {
'"'
~ $d.trans(['"', '', "b", "f", "n", "r", "t"]
=> ['"', '', 'b', 'f', 'n', 'r', 't'])
.subst(/<-[c32..c126]>/, { ord(~$_).fmt('u%04x') }, :g)
~ '"'
}
multi to-json(Positional:D $d) {
return '[ ' ~ $d.map(&to-json).join(', ') ~ ' ]';
}
multi to-json(Hash:D $d) {
return '{ '~ $d.map({ to-json(.key)~' : '~to-json(.value) }).join(', ')~ ' }';
}
multi to-json(Any:U $) { 'null' }
multi to-json(Any:D $s) { die "Can't serialize an object of type "~$s.WHAT.perl}
use JSON::Tiny::Actions;
use JSON::Tiny::Grammar;
sub from-json($text) is export {
my $a = JSON::Tiny::Actions.new();
my $o = JSON::Tiny::Grammar.parse($text, :actions($a));
return $o.ast;
}](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-74-2048.jpg)
![grammar JSON::Tiny::Grammar;
rule TOP { ^ [ <object> | <array> ] $ }
rule object { '{' ~ '}' <pairlist> }
rule pairlist { <?> <pair> * % , }
rule pair { <?> <string> ':' <value> }
rule array { '[' ~ ']' <arraylist> }
rule arraylist { <?> <value>* % [ , ] }
proto token value {*};
token value:sym<number> {
'-'?
[ 0 | <[1..9]> <[0..9]>* ]
[ . <[0..9]>+ ]?
[ <[eE]> [+|-]? <[0..9]>+ ]?
}
token value:sym<true> { <sym> };
token value:sym<false> { <sym> };
token value:sym<null> { <sym> };
token value:sym<object> { <object> };
token value:sym<array> { <array> };
token value:sym<string> { <string> }
token string { " ~ " ( <str> | <str_escape> )* }
token str { <-["tn]>+ }
token str_escape { <["/bfnrt]> | u <xdigit>**4 }](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-75-2048.jpg)
![class JSON::Tiny::Actions;
method TOP($/) { make $/.values.[0].ast };
method object($/) { make $<pairlist>.ast.hash }
method pairlist($/) { make $<pair>>>.ast.flat }
method pair($/) { make $<string>.ast => $<value>.ast }
method array($/) { make $<arraylist>.ast }
method arraylist($/) { make [$<value>>>.ast] }
method string($/) {
make $0.elems == 1
?? ($0[0].<str> || $0[0].<str_escape>).ast
!! join '', $0.list.map({ (.<str> || .<str_escape>).ast });
}
method value:sym<number>($/) { make +$/.Str }
method value:sym<string>($/) { make $<string>.ast }
method value:sym<true>($/) { make Bool::True }
method value:sym<false>($/) { make Bool::False }
method value:sym<null>($/) { make Any }
method value:sym<object>($/) { make $<object>.ast }
method value:sym<array>($/) { make $<array>.ast }
method str($/) { make ~$/ }
method str_escape($/) {
if $<xdigit> {
make chr(:16($<xdigit>.join));
} else {
my %h = '' => "", '/' => "/", 'b' => "b", 'n' => "n",
't' => "t", 'f' => "f", 'r' => "r", '"' => """;
make %h{~$/};
}
}](https://image.slidesharecdn.com/skycon12-121007161710-phpapp02/75/Perl-at-SkyCon-12-76-2048.jpg)
Uploaded byTim Bunce
Perl at SkyCon'12
The document discusses memory profiling and performance profiling techniques for Perl programs, highlighting tools like devel::nytprof and devel::size. It covers how to use these tools for tracking CPU usage, memory consumption, and generating detailed reports on subroutine performance. Additionally, it touches on the evolution of Perl over 25 years and introduces the concept of Perl 6, emphasizing the language's adaptability and rich ecosystem.
More Related Content
Perl at SkyCon'12
- 1.
- 2. Perl Code Profiling MemoryProfiling Perl 5 Perl 6 Tim Bunce - SkyCon’12
- 3. Devel::NYTProf Perl Source CodeProfiler Tim Bunce - SkyCon’12
- 4. Devel::DProf Is Broken $perl -we 'print "sub s$_ { sqrt(42) for 1..100 }; s$_({});n" for 1..1000' > x.pl $ perl -d:DProf x.pl $ dprofpp -r Total Elapsed Time = 0.108 Seconds Real Time = 0.108 Seconds Exclusive Times %Time ExclSec CumulS #Calls sec/call Csec/c Name 9.26 0.010 0.010 1 0.0100 0.0100 main::s76 9.26 0.010 0.010 1 0.0100 0.0100 main::s323 9.26 0.010 0.010 1 0.0100 0.0100 main::s626 9.26 0.010 0.010 1 0.0100 0.0100 main::s936 0.00 - -0.000 1 - - main::s77 0.00 - -0.000 1 - - main::s82
- 5. Profiling 101 The Basics
- 6. What To Measure? CPU Time Real Time Subroutines ? ? Statements ? ?
- 7. Devel::NYTProf Does it all
- 8. Running NYTProf perl -d:NYTProf ... perl -MDevel::NYTProf ... Configure profiler via the NYTPROF env var perldoc Devel::NYTProf for the details To profile code that’s invoked elsewhere: PERL5OPT=-d:NYTProf NYTPROF=file=/tmp/nytprof.out:addpid=1:...
- 9. Reporting: KCachegrind • KCachegrindcall graph - new and cool - contributed by C. L. Kao. - requires KCachegrind $ nytprofcg # generates nytprof.callgraph $ kcachegrind # load the file via the gui
- 10.
- 11. Reporting: HTML • HTMLreport - page per source file, annotated with times and links - subroutine index table with sortable columns - interactive Treemap of subroutine times - generates Graphviz dot file of call graph - -m (--minimal) faster generation but less detailed $ nytprofhtml # writes HTML report in ./nytprof/... $ nytprofhtml --file=/tmp/nytprof.out.793 --open
- 13. Summary Links to annotated source code Link to sortable table of all subs Timings for perl builtins
- 15. Color coding basedon Overall time spent in and below this sub Median Average Deviation relative to rest of this file (in + below) Time between starting this perl statement and starting the next. So includes overhead of calls to perl subs. Timings for each location calling into, or out of, the subroutine
- 17. Treemap showing relative proportions of exclusive time Boxes represent subroutines Colors only used to show packages (and aren’t pretty yet) Hover over box to see details Click to drill-down one level in package hierarchy
- 18.
- 19.
- 20. Questions? For more details see Slides: http://www.slideshare.net/Tim.Bunce/develnytprof-v4-at-yapceu-201008-4906467 Screencast: http://blip.tv/timbunce/devel-nytprof-yapc-asia-2012-6376582
- 21. Perl Memory Use Tim Bunce @ SkyCon’12
- 22. Ouch! $ perl some_script.pl Outof memory! $ $ perl some_script.pl Killed. $ $ perl some_script.pl $ Someone shouts: "Hey! My process has been killed!" $ perl some_script.pl [...later...] "Umm, what's taking so long?"
- 23.
- 24. $ perl -e'system("cat /proc/$$/stat")' # $$ = pid 4752 (perl) S 4686 4752 4686 34816 4752 4202496 536 0 0 0 0 0 0 0 20 0 1 0 62673440 123121664 440 18446744073709551615 4194304 4198212 140735314078128 140735314077056 140645336670206 0 0 134 0 18446744071579305831 0 0 17 10 0 0 0 0 0 0 0 0 0 0 4752 111 111 111 $ perl -e 'system("cat /proc/$$/statm")' 30059 441 346 1 0 160 0 $ perl -e 'system("ps -p $$ -o vsz,rsz,sz,size")' VSZ RSZ SZ SZ 120236 1764 30059 640 $ perl -e 'system("top -b -n1 -p $$")' ... PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 13063 tim 20 0 117m 1764 1384 S 0.0 0.1 0:00.00 perl $ perl -e 'system("cat /proc/$$/status")' ... VmPeak:! 120236 kB VmSize:! 120236 kB <- total (code, libs, stack, heap etc.) VmHWM:! 1760 kB VmRSS:! 1760 kB <- how much of the total is resident in physical memory VmData:! 548 kB <- data (heap) VmStk:! 92 kB <- stack VmExe:! 4 kB <- code VmLib:! 4220 kB <- libs, including libperl.so VmPTE:! 84 kB VmPTD:! 28 kB VmSwap:! 0 kB ... Further info on unix.stackexchange.com
- 25. C Program Code int main(...) { ... } Read-only Data eg “String constants” Read-write Data un/initialized variables Heap (not to scale!) Shared Lib Code Shared Lib R/O Data repeated for each lib Shared Lib R/W Data // C Stack (not the perl stack) System
- 26. $ perl -e'system("cat /proc/$$/maps")' address perms ... pathname 00400000-00401000 r-xp ... /.../perl-5.NN.N/bin/perl 00601000-00602000 rw-p ... /.../perl-5.NN.N/bin/perl 0087f000-008c1000 rw-p ... [heap] 7f858cba1000-7f8592a32000 r--p ... /usr/lib/locale/locale-archive-rpm 7f8592c94000-7f8592e1a000 r-xp ... /lib64/libc-2.12.so 7f8592e1a000-7f859301a000 ---p ... /lib64/libc-2.12.so 7f859301a000-7f859301e000 r--p ... /lib64/libc-2.12.so 7f859301e000-7f859301f000 rw-p ... /lib64/libc-2.12.so 7f859301f000-7f8593024000 rw-p ... ...other libs... 7f8593d1b000-7f8593e7c000 r-xp ... /.../lib/5.NN.N/x86_64-linux/CORE/libperl.so 7f8593e7c000-7f859407c000 ---p ... /.../lib/5.NN.N/x86_64-linux/CORE/libperl.so 7f859407c000-7f8594085000 rw-p ... /.../lib/5.NN.N/x86_64-linux/CORE/libperl.so 7f85942a6000-7f85942a7000 rw-p ... 7fff61284000-7fff6129a000 rw-p ... [stack] 7fff613fe000-7fff61400000 r-xp ... [vdso] ffffffffff600000-ffffffffff601000 r-xp ... [vsyscall]
- 27. $ perl -e'system("cat /proc/$$/smaps")' # note ‘smaps’ not ‘maps’ address perms ... pathname ... 7fb00fbc1000-7fb00fd22000 r-xp ... /.../5.10.1/x86_64-linux/CORE/libperl.so Size: 1412 kB <- size of executable code in libperl.so Rss: 720 kB <- amount that's currently in physical memory Pss: 364 kB Shared_Clean: 712 kB Shared_Dirty: 0 kB Private_Clean: 8 kB Private_Dirty: 0 kB Referenced: 720 kB Anonymous: 0 kB AnonHugePages: 0 kB Swap: 0 kB KernelPageSize: 4 kB MMUPageSize: 4 kB ... repeated for every segment ... ... repeated for every segment ...
- 28. Memory Pages ✦ Process view: ✦ Single large memory space. Simple. ✦ Operating System view: ✦ Memory is divided into pages ✦ Pages are loaded to physical memory on demand ✦ Mapping can change without the process knowing
- 29. C Program Code Read-only Data Memory is divided into pages Page size is typically 4KB Read-write Data Heap ← Page ‘resident’ in physical memory ← Page not resident RSS “Resident Set Size” is how much process memory is Shared Lib Code currently in physical memory Shared Lib R/O Data Shared Lib R/W Data C Stack System
- 30. Key Point ✦ Don’t use Resident Set Size (RSS) ✦ It can shrink even while the process size grows. ✦ Heap size or Total memory size is a good indicator.
- 31.
- 32. Heap ← Your perl stuff goes here • Heap is managed by malloc() • Memory freed is rarely returned to the operating system • Heap grows but rarely shrinks
- 33. Perl Data Anatomy Integer (IV) String (PV) Number with a string Head Body Data Illustrations from illguts
- 34.
- 35. Glob (GV) Symbol Table (Stash) Sub (CV) lots of tiny chunks!
- 36. Devel::Peek • Gives you a textual view of data $ perl -MDevel::Peek -e '%a = (42 => "Hello World!"); Dump(%a)' SV = IV(0x1332fd0) at 0x1332fe0 REFCNT = 1 FLAGS = (TEMP,ROK) RV = 0x1346730 SV = PVHV(0x1339090) at 0x1346730 REFCNT = 2 FLAGS = (SHAREKEYS) ARRAY = 0x1378750 (0:7, 1:1) KEYS = 1 FILL = 1 MAX = 7 Elt "42" HASH = 0x73caace8 SV = PV(0x1331090) at 0x1332de8 REFCNT = 1 FLAGS = (POK,pPOK) PV = 0x133f960 "Hello World!"0 CUR = 12 <= length in use LEN = 16 <= amount allocated
- 37. Devel::Size • Gives you a measure of the size of a data structure $ perl -MDevel::Size=total_size -le 'print total_size( 0 )' 24 $ perl -MDevel::Size=total_size -le 'print total_size( [] )' 64 $ perl -MDevel::Size=total_size -le 'print total_size( {} )' 120 $ perl -MDevel::Size=total_size -le 'print total_size( [ 1..100 ] )' 3264 • Is very fast, and accurate for most simple data types. • Has limitations and bugs, but is the best tool we have.
- 38.
- 39. What? ✦ Track memory size over time? ✦ See where memory is allocated and freed? ✦ Experiments with Devel::NYTProf ✦ Turned out to not seem useful
- 40. Space in Hiding ✦ Perl tends to consume extra memory to save time ✦ This can lead to surprises, for example: ✦ sub foo { my $var = "X" x 10_000_000; } foo(); # ~20MB still used after return! ✦ sub bar{ my $var = "X" x 10_000_000; bar($_[0]-1) if $_[0]; # recurse } bar(50); # ~1GB still used after return!
- 41.
- 42. The Plan ✦ Extend Devel::Size ✦ Add a C-level callback hook ✦ Add some kind of "data path name" for the callback to use ✦ Add a function to Devel::Size to return the size of everything ✦ Stream the data to disk ✦ Write tools to visualize the data ✦ Add multi-phase scan 1. scan symbol tables, skip where ref count > 1 2. process the skipped items 3. scan arenas for other values (e.g. leaks) ✦ Write tool to compare two sets of data
- 43. The Status ✓ Add a C-level callback hook ✓ Add some kind of "data path name" for the callback to use ✓ Add a function to Devel::Size to return the size of everything. ✓ Stream the data to disk ✓ Write tools to visualize the data • Will become a separate distribution • “Devel::SizeMeGraph”? • Source repo available by Sunday • Ready to demonstrate
- 44.
- 45. Questions? For more details see Full slides: http://www.slideshare.net/Tim.Bunce/perl-memory-use-yapcasia2012 Screencast: http://blip.tv/timbunce/perl-memory-use-and-devel-sizeme-at-yapc- asia-2012-6381282 Tim.Bunce@pobox.com http://blog.timbunce.org @timbunce
- 46. Perl A Summary ofthe Onions Tim Bunce – SkyCon’12
- 47.
- 48. - Perl 5 isn’t the new kid on the block - Perl is 25 years old - Perl 5 is 18 years old - A mature language with a mature culture
- 49. From “The Stateof the Onion 10” by Larry Wall, 2006
- 50. - Perl is 25 years old - Perl 5 is 18 years old - Perl 6 was conceived 12 years ago - Perl 6 “Rakudo Star” is 2 years old
- 51. “CPAN is mylanguage, Perl is my VM” - Vast library of free code modules on “CPAN” - Over 5,100 active authors (making releases) - Over 26,000 distributions (110,000 modules) - ~1,000 uploads per month (by ~500 authors) - ~250 new distributions per month - Automated smoke testing for all uploads
- 52.
- 53. Dependency Analysis availablefor all Modules http://deps.cpantesters.org/?module=Moose;perl=latest
- 54.
- 55. Perl 5 Development -5.10 – 2007 - 5.12 – 2010 - 5.14 – 2011 - 5.16 – 2012 - 5.17.4 latest monthly development release - 5.18 – due May 2013
- 56. Perl 5 NewFeatures - Refactored internals many fixes, more speed, less memory - New language features (state, say, //, autodie, ...) - Language feature management - Unicode 6.1 and many new Unicode features - Many powerful new regex features See http://www.slideshare.net/rjbs/whats-new-in-perl-v510-v516
- 57.
- 58. Demo Regexp::Debuger See http://www.youtube.com/watch?v=zcSFIUiMgAs
- 59. A Culture ofTesting -2002: Perl 5.8.0 had 26,725 core tests +41,666 more for bundled libraries etc. -2007: Perl 5.10.0 has 78,883 core tests +109,427 -2010: Perl 5.11.5 has 191,008 core tests +167,015 -2012: Perl 5.16.0 has 262,370 core tests +261,776
- 60. Perl 6 Another memberof the Perl language family
- 61. Learn it once,use it many times. Learn as you go. Many acceptable levels of competence. Multiple ways to say the same thing. No shame in borrowing. Indeterminate dimensionality. Local ambiguity is okay. Natural Language Punctuation by prosody and inflection. Principles in Perl Disambiguation by number, case and word order. Topicalization. Discourse structure. Pronominalization. No theoretical axes to grind. Style not enforced except by peer pressure. Cooperative design. “Inevitable” Divergence. http://www.wall.org/~larry/natural.html
- 62. Timeline 2000: Perl 6conceived (after a smashed coffee mug) 2001-2004: Initial design docs 2005: First prototype, pugs (in Haskell) 2005+ Continual radical evolution (the whirlpool) 2010: 1st Rakudo Star release 2012: 17th Rakudo Star release Mostly implemented in Perl6 (>60% and rising)
- 63. “If we'd donePerl 6 on a schedule, you'd have it by now. And it would be crap.” —Larry Wall, 2002 “Do it right.” and “It's ready when it's ready.” Freedom to explore deeply and change “Truly radical and far-reaching improvements over the past few years.”
- 64. “We've spent adecade stealing the very best ideas from the best programming languages, and making them simple and practical for mortal developers to use.” —Damian Conway
- 65. “Should be calledPerl 8 or Perl 9” “feedback at many levels from multiple implementations”
- 66. Multiple Implementations Twomain implementations: Rakudo - built on Parrot Compiler Toolchain Niecza - targeting the CLR (.NET and Mono) Plus: STD, viv, Perlito, Pugs and others Work on a JVM implementation is starting All sharing a common test suite See http://perl6.org/compilers
- 67. Some Perl 6Features Rich set of operators and meta-operators Rich type system Rich object system, including roles/traits A full Meta Object Protocol Multiple dispatch using types and expressive signatures Gradual typing Lazy lists and iterators, with controllable eagerness Deep introspection Native Call Interface Representational polymorphism Powerful matching and parsing with subclassable grammars
- 68. Series and Reduction ‣ say 1, 2, 4 ... 1024; 1 2 4 8 16 32 64 128 256 512 1024 ‣ my @fib = 1, 1, *+* ... *; # infinite say @fib[^10]; # 0..9 1 1 2 3 5 8 13 21 34 55 89 ‣ say [*] 1..10; # reduction, use any operator 3628800 ‣ sub postfix:<!>($n) { [*] 1..$n } say 10! 3628800
- 69. Multiple Dispatch ‣ multi fact(0) { 1 } multi fact($n) { $n * fact($n – 1) } ‣ multi fib(0) { 0 } multi fib(1) { 1 } multi fib($n) { fib($n – 1) + fib($n – 2) } ‣ multi quicksort([]) { () } multi quicksort([$pivot, *@rest]) { my @before = @rest.grep(* < $pivot); my @after = @rest.grep(* >= $pivot); (quicksort(@before), $pivot, quicksort(@after)) }
- 70. Native Call Interface subPQexecPrepared( - OpaquePointer $conn, Str $statement_name, Int $n_params, CArray[Str] $param_values, CArray[int] $param_length, CArray[int] $param_formats, Int $resultFormat) - returns OpaquePointer is native('libpq') { ... } Also supports structures and callbacks.
- 71. my @suits = < ♣ ♢ ♡ ♠ >; my @ranks = 2..10, < J Q K A >; # concatenate each rank with each suit my @deck = @ranks X~ @suits; # create hash of card to points value my %points = @deck Z ( (2..10, 10, 10, 10, 11) X+ (0,0,0,0) ); # grab five cards from the deck my @hand = @deck.pick(5); # display my hand say ~@hand; # tell me how many points it's worth say [+] %points{@hand};
- 72. @xyz»++ # increment all elements of @xyz @x = @a »min« @b # @x is smallest of @a and @b $mean = ([+] @a) / @a # calculate mean of @a $sumsq = [+] (@x »**» 2) # sum of squares of @x $fact = [*] 1..$n # $n factorial for %hash.kv -> $k, $v { say "$k: $v" }
- 73. Example Module JSON::Tiny https://github.com/moritz/json
- 74. module JSON::Tiny; proto to-json($)is export {*} multi to-json(Real:D $d) { ~$d } multi to-json(Bool:D $d) { $d ?? 'true' !! 'false'; } multi to-json(Str:D $d) { '"' ~ $d.trans(['"', '', "b", "f", "n", "r", "t"] => ['"', '', 'b', 'f', 'n', 'r', 't']) .subst(/<-[c32..c126]>/, { ord(~$_).fmt('u%04x') }, :g) ~ '"' } multi to-json(Positional:D $d) { return '[ ' ~ $d.map(&to-json).join(', ') ~ ' ]'; } multi to-json(Hash:D $d) { return '{ '~ $d.map({ to-json(.key)~' : '~to-json(.value) }).join(', ')~ ' }'; } multi to-json(Any:U $) { 'null' } multi to-json(Any:D $s) { die "Can't serialize an object of type "~$s.WHAT.perl} use JSON::Tiny::Actions; use JSON::Tiny::Grammar; sub from-json($text) is export { my $a = JSON::Tiny::Actions.new(); my $o = JSON::Tiny::Grammar.parse($text, :actions($a)); return $o.ast; }
- 75. grammar JSON::Tiny::Grammar; rule TOP { ^ [ <object> | <array> ] $ } rule object { '{' ~ '}' <pairlist> } rule pairlist { <?> <pair> * % , } rule pair { <?> <string> ':' <value> } rule array { '[' ~ ']' <arraylist> } rule arraylist { <?> <value>* % [ , ] } proto token value {*}; token value:sym<number> { '-'? [ 0 | <[1..9]> <[0..9]>* ] [ . <[0..9]>+ ]? [ <[eE]> [+|-]? <[0..9]>+ ]? } token value:sym<true> { <sym> }; token value:sym<false> { <sym> }; token value:sym<null> { <sym> }; token value:sym<object> { <object> }; token value:sym<array> { <array> }; token value:sym<string> { <string> } token string { " ~ " ( <str> | <str_escape> )* } token str { <-["tn]>+ } token str_escape { <["/bfnrt]> | u <xdigit>**4 }
- 76. class JSON::Tiny::Actions; method TOP($/) { make $/.values.[0].ast }; method object($/) { make $<pairlist>.ast.hash } method pairlist($/) { make $<pair>>>.ast.flat } method pair($/) { make $<string>.ast => $<value>.ast } method array($/) { make $<arraylist>.ast } method arraylist($/) { make [$<value>>>.ast] } method string($/) { make $0.elems == 1 ?? ($0[0].<str> || $0[0].<str_escape>).ast !! join '', $0.list.map({ (.<str> || .<str_escape>).ast }); } method value:sym<number>($/) { make +$/.Str } method value:sym<string>($/) { make $<string>.ast } method value:sym<true>($/) { make Bool::True } method value:sym<false>($/) { make Bool::False } method value:sym<null>($/) { make Any } method value:sym<object>($/) { make $<object>.ast } method value:sym<array>($/) { make $<array>.ast } method str($/) { make ~$/ } method str_escape($/) { if $<xdigit> { make chr(:16($<xdigit>.join)); } else { my %h = '' => "", '/' => "/", 'b' => "b", 'n' => "n", 't' => "t", 'f' => "f", 'r' => "r", '"' => """; make %h{~$/}; } }
- 77. Perl 6 Already fullof awesome Hundreds of examples on http://rosettacode.org Developers happy to stay in stealth mode for now Get ahead of the revolution: http://perl6.org
- 78.
- 79. Perl has a massivelibrary of reusable code has a culture of best practice and testing has a happy welcoming growing community has a great future in Perl 5 and Perl 6 is a great language for getting your job done for the last 25 years, and the next 25!
- 80. Questions? See also http://www.slideshare.net/Tim.Bunce/perl-myths-200909 http://perlmonks.org http://search.cpan.org http://rakudo.org/how-to-help http://blog.timbunce.org @timbunce
- 81.