1. YAML: A New Language for Data INGY presents: YAML@ YAPC

2. YAML: A New Language for Data &whois("Brian Ingerson"); Libraries and Mainframes Assembler to Perl Term::Scraper Inline YAML use YourBrainForOnceDude; ActiveState FatPort DataBuilt

3. YAML: A New Language for Data What is YAML? Your Average Meat Loaf? Yasser Arafat Making Lasers? You'll Argue My Logic? YAGNI Ass Mutha Load? whY Are Mongers Laughing? Yet Another Module Legend? Yet Another Markup Language ??? YAML Ain’t Markup Language!

4. YAML: A New Language for Data What is YAML? YAML is a Data Serialization Language. A New Language for Data Modeled after Perl-like structures But not just intended for Perl XML is a Markup Language Sort of... We use XML mostly for serialization

5. YAML: A New Language for Data YAML Design Goals YAML design goals: - YAML documents are very readable by humans. - YAML interacts well with scripting languages. - YAML uses host languages native data structures. - YAML has a consistent information model. - YAML enables stream-based processing. - YAML is expressive and extensible. - YAML is easy to implement. (cat | ysh)

6. YAML: A New Language for Data Ingy's Design Goals To achieve Human/Computer Nirvana High Data/Markup (Signal/Noise) Ratio To be the world's best Data::Dumper To be great for Configs, Caches, and Logs One Serialization to Rule Them All...... and in the YAML bind them. Other Goals: Unicode based Speedy parsing Alternative to XML (for some applications)

7. YAML: A New Language for Data Where YAML Came From Inline.pm Data::Denter Clark Evans Oren Ben-Kiki sml-dev yaml-core mailing list mini P5P 2000+ messages last year irc.debian.org #yaml Summits

8. YAML: A New Language for Data Data::Denter and Inline md5 : cc9b569052f4daa5b343b1dcb94dd2bc name : e_cc9b language : C date_compiled : Wed Jun 12 12:48:00 2002 inline_version : 0.43 ILSM : % module : Inline::C suffix : bundle type : compiled Config : % apiversion : 5.005 archname : darwin ccflags : -g -pipe -pipe -fno-common osname : darwin osvers : 1.4 so : dylib version : 5.6.0

9. YAML: A New Language for Data Influences --- scripting languages: - Perl - Python - C - Java standards: - RFC0822 (MAIL) - RFC1866 (HTML) - RFC2045 (MIME) - RFC2396 (URI) protocols: - SAX - SOAP - XML

10. YAML: A New Language for Data YAML Syntax Basics Mappings Sequences Streams and Documents Comments Scalars Simple Quoted Block Folded Wiki Escaping Anchors & Aliases

11. YAML: A New Language for Data Mappings A YAML mapping is like a Perl hash Unordered Key/Value pairs Separated by ': ' (space is mandatory) --- name: Benjamin rank: Private serial number: 1234567890 12:34 PM: My favorite time

12. YAML: A New Language for Data Sequences A YAML sequence is like a Perl array An ordered collection of data YAML has a bullet like syntax '- ' --- - red - white - blue - pinko

13. YAML: A New Language for Data A YAML Grocery List --- Fruits: - Apples - Tomatoes Veggies: - Spinach - Broccoli Meats: - Burgers - Shrimp Household: - Candles - Incense - Toilet Duck

14. YAML: A New Language for Data The Matrix --- - - 3 - 5 - 7 - - 0 - 7 - - 9 - 1

15. YAML: A New Language for Data Outline - Intro - Part 1: - Up - Down - Side to Side - Part 2: - Here - There - Underwear - Part 3: - The Good - The Bad - The Ingy

16. YAML: A New Language for Data Comments Comments/blank lines can go almost anywhere Must not be ambiguous with content Comments begin '# ' (almost like Perl) # comment before document --- #DIRECTIVE # comment foo: bar # inline comment phone: number #555-1234 ### Comment fact: fiction --- blue: bird # Comment

17. YAML: A New Language for Data Scalars A YAML scalar is like a Perl scalar YAML has many scalar forms TMTOWTDI --- simple: look ma, no quotes quoted: - 'Single quoted. Like Perl, no escapes' - "Double quotes.\nLike Perl, has escapes" - | A YAML block scalar. Much like Perl's here-document.

18. YAML: A New Language for Data Simple (unquoted) Scalar Can use for almost all simple values Some content limitations --- simple key: simple value this value: can span multiple lines but the key cannot. it would need quotes stuff: - foo - 42 - 3.14 - 192.168.2.98 - m/^(.*)\//

19. YAML: A New Language for Data Single Quoted Scalar No escapes (like Perl) Use when simple won't work --- 'key contains: colon': '$19.99' or: ' value has leading/trailing whitespace ' 'key spans lines': 'double ticks \ for ''escaping'''

20. YAML: A New Language for Data Double Quoted Scalar Allows escaping (like Perl) --- The spec says: "The double quoted style variant adds escaping to the 'single quoted' style variant." like this: "null->\z newline->\n bell->\a smiley->\u263a" self escape: "Brian \"Ingy\" Ingerson"

21. YAML: A New Language for Data Block Scalar Blocks are like here-docs on vitamins Newlines are hard Termination is determined by indentation --- what is this: | is it: a YAML mapping or just: a string chomp me: |- sub foo { print "Love me do!"; }

22. YAML: A New Language for Data Embedding YAML in YAML No Escaping of Markup Required Simply use the Block Form YAML Test Suite does this --- #YAML:1.0 old doc: | --- #YAML:1.0 tools: - XML - XSLT new doc: | --- #YAML:1.0 tools: - YAML - cYATL

23. YAML: A New Language for Data Folded Scalar Folded scalars work like HTML Single newlines indicate a space character. Empty lines mean a hard newline --- - > Copyright © 2001 Brian Ingerson, Clark Evans & Oren Ben-Kiki, all rights reserved. This document may be freely copied provided that it is not modified. Next paragraph. - foo

24. YAML: A New Language for Data Wiki Content Similar to POD or some Wikis Indented text preserves line endings --- The YAML Specification starts out by saying: > YAML(tm) (rhymes with "camel") is a straightforward machine parsable data serialization format designed for human readability and interaction with scripting languages such as Perl and Python. YAML documents are very readable by humans. YAML interacts well with scripting languages. YAML uses host languages' native data structures. Please join us, the mailing list is at SourceForge.

25. YAML: A New Language for Data Nested Scalar Key Sometimes you want fancy blocks for map keys Know what I mean? --- ? >+ Even a key can: 1) Be Folded 2) Have Wiki : cool, eh?

26. YAML: A New Language for Data Anchors and Aliases YAML can handle duplicate and recursive data It uses an alias mechanism Aliases do not span documents --- Hey Jude: &chorus - na, na, na, - &4 na, na, na, na, - *4 - Hey Jude. - *chorus

27. YAML: A New Language for Data A Hard Example Here is an example of preserving hard refs Not sexy, but neither are hard refs... use YAML; $a=\\\\\\\\"foo"; $b=$$$$a; print Dump [$a,$b],[$b,$a];

28. YAML: A New Language for Data Using YAML.pm Just like Data::Dumper perl -MData::Dumper -e 'print Dumper \%INC' perl -MYAML -e 'print Dump \%INC' 10 character savings over D::D Basic API Dump Load Other Functions: DumpFile LoadFile freeze(), thaw() # POE Object Oriented # Not discussed

29. YAML: A New Language for Data YAML vs Data::Dumper YAML Pros: Cleaner format Safe deserialization Hashes sorted by default Escapes unprintables Supports GLOB, CODE, Regexp and Filehandle Interacts with Ruby, Python, Java etc Data::Dumper Pros: Familiar Perl Syntax Fast C implementation Mature

30. YAML: A New Language for Data Using YAML in Perl Code my $calendar = Load <<'...'; jan: [january, 31] feb: [february, 28] mar: [march, 31] apr: [april, 30] may: [may, 31] jun: [june, 30] jul: [july, 31] aug: [august, 31] sep: [september, 30] oct: [october, 31] nov: [november, 30] dec: [december, 31]... $july_days = $calendar->{jul}[1];

31. YAML: A New Language for Data Some Real YAML Applications yaml2outline phone2yaml xyx YAML.pm uses YAML! Changes Test suite perl test-prd.pl

32. YAML: A New Language for Data A Quick Tour of the YAML Spec http://www.yaml.org/spec 1.Intro 2.Preview Nice Examples 3.Information Models 4.Serialization Syntax 160 productions 5.Transfer Methods

33. YAML: A New Language for Data Intermediate YAML Syntax Whitespace...... is the devil Headers and Directives Inline Collections Complex Keys Transfer Families Implicit Typing YAML Builtin Types Perl Builtin Types

34. YAML: A New Language for Data Whitespace There is a special room in the hot place reserved for the person who invented tabs. YAML has it harder than Python By default YAML disallows TABS for indenting But we have #TAB just in case Modern editors will have YAML support Keep computing tidy. Burn all tabs!

35. YAML: A New Language for Data Indentation Rules Use same number of spaces for a given scope --- two: - few four: - more blocks: - | # Beware the TAB sub spoon { -------- fork } - |2 QTY DESC PRICE 1) 3 Blind Mice Free 2) 5 Dollar Bill $10.00

36. YAML: A New Language for Data Headers and Directives Headers start all documents Directives and top level qualifiers go there Two directives: #YAML & #TAB First document can be headerless headerless: first document --- #YAML:1.0 #TAB:NONE --- > folded top level scalar --- &1 recurse: *1 --- - simple header

37. YAML: A New Language for Data Inline Collections So far YAML structure resembles Python Time for a little TMTOWTDI!!! --- seq: [ 14, 34, 55 ] map: {purple: rain, blue: skies} mixed: {sizes: [9, 11], shapes: [round]} span: {players: [who, what, I don't know], positions: [first, second, third]}

38. YAML: A New Language for Data The Matrix Revisited # Inline sequences make data more compact --- - [3, 5, 7] - [0, 0, 7] -[9, 1, 1] # Above is identical to below --- [[3, 5, 7], [0, 0, 7], [9, 1, 1]] # A 3D Matrix --- - [[3, 5, 7], [0, 0, 7], [9, 1, 1]] - [[0, 0, 7], [9, 1, 1], [3, 5, 7]] - [[9, 1, 1], [3, 5, 7], [0, 0, 7]]

39. YAML: A New Language for Data Complex Keys In Perl, all hash keys are strings YAML doesn't have that restriction YAML is Perl6 enabled! --- ? - Kane - Kudra : engaged [Damian, Dominus]: engaging

40. YAML: A New Language for Data Transfer Families In YAML, every node has a type These types can be user defined Every type has a unique URI same: - 42 - !int 42 - !yaml.org/int 42 - !http://yaml.org/int 42 perl: - !perl/Foo::Bar {} - !perl.yaml.org/Foo::Bar {} - !http://perl.yaml.org/Foo::Bar {}

41. YAML: A New Language for Data More Transfer Families You can define your own types '^' is used for abbreviating URI's may someday be real schema locations domain specific document: - !http://foobar.org/foo [] - !foobar.org/^foo - !^bar xxx - !^baz yyy

42. YAML: A New Language for Data Implicit Typing Simple (unquoted) Strings have implicit types These types have predefined regexps --- - 42 # integer - -3.14 # floating point - 6.02e+23 # scientific notation - 0xCAFEBABE # hexadecimal int - 2001-09-11 # ISO8601 time - '2001-09-11' # string - + # boolean true - (false) # alternate boolean - ~ # null (undef in Perl) - 123 Main St # string

43. YAML: A New Language for Data Roundtripping YAML processes should preserve types Especially within a language/application domain Should warn otherwise Python preserves Perl typeglobs (!perl/glob:) Perl preserves !python/tuple Gets complicated with complex keys, etc YAML::Node is the Perl roundtripping object A tied hash/array/scalar w/ YAML magic

44. YAML: A New Language for Data YAML Builtin Types YAML has a good number of builtin types Some are implicit, some aren't --- - !str YAML, YAML, YAML! - !int 42 - !float 0.707 - !time 2001-12-14T21:59:43.10-05:00 - !bool 1 - !null 0 - !binary MWYNG84BwwEeECcgggoBADs=

45. YAML: A New Language for Data Perl Builtin Types Perl also has a number of official types These are under YAML/Ingy's control !http://perl.yaml.org/type --- - !perl/Foo::Bar {} # hash-based class - !perl/@Foo::Bar [] # array-based class - !perl/$Foo::Bar '' # scalar-based class - !perl/glob: # typeglob - !perl/code: # code reference - !perl/ref: # hard reference - !perl/regexp: # regular expression - !perl/regexp:Foo::Bar # blessed regexp

46. YAML: A New Language for Data Introducing the YAML Shell ysh - the YAML Shell Perl => YAML YAML => Perl Term::Readline support Logging Great way to learn Perl Distributed with YAML.pm

47. YAML: A New Language for Data Fun With GLOBs in ysh *foo *INC *ARGV *$ *_ *STDIN *YAML:: [*x, *y]

48. YAML: A New Language for Data Perl's Symbol Table (The Full Monty!) ysh -uc -i4 -L *main:: 10000+ lines recursive (main::) ISA, IO:, CODE: &6, ENV:, Config:(tied!), INC:, SIG:, Bits:, Offsets:, *|

49. YAML: A New Language for Data More ysh Fun open $fh, $0; open $fh[0], $0; seek $fh, 100, 0; close $fh; scalar `perl -h` fork < Changes Roundtripping $x = \$x;

50. YAML: A New Language for Data The World Wide YAML Shell http://wwysh.yaml.org Regression Test Farm Multiple Implementations

51. YAML: A New Language for Data Self Serializing Objects YAML::Node Family URI Ordered keys Foo::yaml_dump() Foo::yaml_load()

52. YAML: A New Language for Data Advanced YAML Concepts YAML::Node Information Models YAML Schemas YPATH & YATL YAML::Node YAML::Bless()

53. YAML: A New Language for Data YAML::Node Need more control? YAML::Node is the ticket Tied wrapper abound a plain hash, array or scalar Contains extra info: YAML Family Key order YAML::Bless($node) $y->bless($foo); Associates a ynode with a regular node YAML::Blessed($node) May be a way to support complex keys in Perl

54. YAML: A New Language for Data Information Models Syntax Model parser/emitter Serial Model loader/dumper Generic Model application loader/dumpers Native Model user application (your script)

55. YAML: A New Language for Data YAML and Schemas Key Order Optional Fields Validation (enums) Structure

56. YAML: A New Language for Data YAML Schema --- #YAML:1.0 NAME: AddressEntry HASH: - NAME: Name HASH: - NAME: First - NAME: Last OPTIONAL: yes - NAME: EmailAddresses ARRAY: yes - NAME: Phone ARRAY: yes HASH: - NAME: Type OPTIONAL: yes - NAME: Number

57. YAML: A New Language for Data YAML Instance w/ Schema --- #YAML:1.0 AddressEntry: Name: First: Brian EmailAddresses: - ingy@CPAN.org - ingy@ttul.org Phone: - Type: Work Number: 604-333-4567 - Number: 843-444-5678

58. YAML: A New Language for Data libyaml - The core YAML engine One engine for Perl, Python, Tcl, Ruby, PHP Maybe Java?? YAML.pm will bind using Inline! Thank you Neil! Thank you Clark!

59. YAML: A New Language for Data YAML People Clark Evans - Father of YAML - libyaml,Python Oren Ben-Kiki - The Master Mind - Java Brian Ingerson - Perl Watchdog - YAML.pm Neil Watkiss - Boy Wonder - libyaml Steve and Ryan - The XP factor - Python, Ruby Rolf Veen - The German Connection - Java Jason Diamond - The Lost Soul - C# Neil Kandalgoankar - brev - YAML.py.old Shane Caraveo - Mr 10 Rings - YAML.php.old Andrew Kurn - The Philosopher Preben Peppe Guldber - vim Master - yaml.syn Why - The Lucky Stiff - YAML.rb

60. YAML: A New Language for Data Resources: www.yaml.org http://www.yaml.org http://www.yaml.org/spec yaml-core@lists.sourceforge.net http://wiki.yaml.org perldoc YAML http://wwysh.yaml.org

61. YAML: A New Language for Data THE END...