YAML with perl
思うところあってYAMLについてお勉強。
YAML 1.1ドキュメントを読んでみる(blockquote部分は超適当訳)。
パーサは YAML.pm v0.66。Perl v5.8.7 (on Cygwin)。
サンプルスクリプト
#!/usr/bin/perl use strict; use warnings; use YAML; use Data::Dumper; my @datareflist = Load(<<'EOF'); # something yaml code EOF print ">||\n##### yaml #####\n"; print Dump @datareflist; print "\n##### data #####\n"; print Dumper @datareflist; print "||<\n";
Collections
YAML では block collection のスコープを示すためにインデントを使う。
Block sequence を記述するためにはエントリのアタマに dash and space ('- ')を使う。
Mapping を記述するためには colon and space (': ')を使う。
Example 2.1. Sequence of Scalars(ball players)
- Mark McGwire - Sammy Sosa - Ken Griffey
##### yaml #####
---
- Mark McGwire
- Sammy Sosa
- Ken Griffey
##### data #####
$VAR1 = [
'Mark McGwire',
'Sammy Sosa',
'Ken Griffey'
];Example 2.2. Mapping Scalars to Scalars(player statistics)
hr: 65 # Home runs avg: 0.278 # Batting average rbi: 147 # Runs Batted In
##### yaml #####
---
avg: '0.278 # Batting average'
hr: '65 # Home runs'
rbi: '147 # Runs Batted In'
##### data #####
$VAR1 = {
'hr' => '65 # Home runs',
'avg' => '0.278 # Batting average',
'rbi' => '147 # Runs Batted In'
};Example 2.3. Mapping Scalars to Sequences (ball clubs in each league)
american: - Boston Red Sox - Detroit Tigers - New York Yankees national: - New York Mets - Chicago Cubs - Atlanta Braves
##### yaml #####
---
american:
- Boston Red Sox
- Detroit Tigers
- New York Yankees
national:
- New York Mets
- Chicago Cubs
- Atlanta Braves
##### data #####
$VAR1 = {
'american' => [
'Boston Red Sox',
'Detroit Tigers',
'New York Yankees'
],
'national' => [
'New York Mets',
'Chicago Cubs',
'Atlanta Braves'
]
};Example 2.4. Sequence of Mappings (players’ statistics)
- name: Mark McGwire hr: 65 avg: 0.278 - name: Sammy Sosa hr: 63 avg: 0.288
##### yaml #####
---
- avg: 0.278
hr: 65
name: Mark McGwire
- avg: 0.288
hr: 63
name: Sammy Sosa
##### data #####
$VAR1 = [
{
'hr' => '65',
'avg' => '0.278',
'name' => 'Mark McGwire'
},
{
'hr' => '63',
'avg' => '0.288',
'name' => 'Sammy Sosa'
}
];
YAML はインデントのかわりにスコープを明示する indicators を明示する、flow style ももっている。
Flow sequence はコンマで区切られた、'[]'中のリストで記述する。
Flow mappings は同様に '{}' 中のリストで記述する。
Example 2.5. Sequence of Sequences
- [name , hr, avg ] - [Mark McGwire, 65, 0.278] - [Sammy Sosa , 63, 0.288]
##### yaml #####
---
-
- name
- hr
- avg
-
- Mark McGwire
- 65
- 0.278
-
- Sammy Sosa
- 63
- 0.288
##### data #####
$VAR1 = [
[
'name',
'hr',
'avg'
],
[
'Mark McGwire',
'65',
'0.278'
],
[
'Sammy Sosa',
'63',
'0.288'
]
];Example 2.6. Mapping of Mappings
Mark McGwire: {hr: 65, avg: 0.278} Sammy Sosa: { hr: 63, avg: 0.288 }
これ、そのままだと YAML.pl はエラーになる。'{}' 内を複数行にするとダメみたいだ。
YAML Error: Inconsistent indentation level Code: YAML_PARSE_ERR_INCONSISTENT_INDENTATION Line: 3 Document: 1
##### yaml #####
---
Mark McGwire:
avg: 0.278
hr: 65
Sammy Sosa:
avg: 0.288
hr: 63
##### data #####
$VAR1 = {
'Mark McGwire' => {
'hr' => '65',
'avg' => '0.278'
},
'Sammy Sosa' => {
'hr' => '63',
'avg' => '0.288'
}
};
Structures
YAMLでは3つの dash ('---')を使って stream 中の documents をわける。
3つの dots ('...') は、communication channels 中で使うための、新しい documents のはじまらない、document のおわりを示す。
Comment 行は Octothrope (hash, sharp, number sign ともいう: '#') ではじまる。
Example 2.7. Two Documents in a Stream (each with a leading comment)
# Ranking of 1998 home runs --- - Mark McGwire - Sammy Sosa - Ken Griffey # Team ranking --- - Chicago Cubs - St Louis Cardinals
##### yaml #####
---
- Mark McGwire
- Sammy Sosa
- Ken Griffey
---
- Chicago Cubs
- St Louis Cardinals
##### data #####
$VAR1 = [
'Mark McGwire',
'Sammy Sosa',
'Ken Griffey'
];
$VAR2 = [
'Chicago Cubs',
'St Louis Cardinals'
];Example 2.8. Play by Play Feed from a Game
--- time: 20:03:20 player: Sammy Sosa action: strike (miss) ... --- time: 20:03:47 player: Sammy Sosa action: grand slam ...
YAML.pm は '...' を解釈しないのか?
YAML Error: Invalid element in map Code: YAML_LOAD_ERR_BAD_MAP_ELEMENT Line: 5 Document: 1
くりかえされる nodes は anchor ( ampersand '&')によって示される。
それらは以降 (asterisk '*' による参照で) aliase される。
Example 2.9. Single Document with Two Comments
--- hr: # 1998 hr ranking - Mark McGwire - Sammy Sosa rbi: # 1998 rbi ranking - Sammy Sosa - Ken Griffey
'hr: # 1998 hr ranking' みたいな '#' がアタマにこない場合のコメントは YAML.pm は解釈しないみたいだ。Example 2.2 でもコメントのつもりがまとめて文字列扱いされてるし。
YAML Error: Inconsistent indentation level Code: YAML_PARSE_ERR_INCONSISTENT_INDENTATION Line: 3 Document: 1
Example 2.10. Node for "Sammy Sosa" appears twice in this document
--- hr: - Mark McGwire # Following node labeled SS - &SS Sammy Sosa rbi: - *SS # Subsequent occurrence - Ken Griffey
##### yaml #####
---
hr:
- Mark McGwire
- Sammy Sosa
rbi:
- Sammy Sosa
- Ken Griffey
##### data #####
$VAR1 = {
'hr' => [
'Mark McGwire',
'Sammy Sosa'
],
'rbi' => [
'Sammy Sosa',
'Ken Griffey'
]
};
Question mark and space ('? ') は複合(complex) mapping key を示す。
Block collection の中では、"key: value" の対は '- ', ': ' または '? ' のすぐ後ろに記述することができる。
Example 2.11. Mapping between Sequences
? - Detroit Tigers - Chicago cubs : - 2001-07-23 ? [ New York Yankees, Atlanta Braves ] : [ 2001-07-02, 2001-08-12, 2001-08-14 ]
これもそのままだと YAML.pm は解釈してくれない。このへんまでオトす。
? [Detroit Tigers, Chicago cubs] : [2001-07-23] ? [ New York Yankees, Atlanta Braves ] : [ 2001-07-02, 2001-08-12, 2001-08-14 ]
##### yaml #####
---
ARRAY(0x1037ad2c):
- 2001-07-23
##### data #####
$VAR1 = {
'ARRAY(0x1037ad2c)' => [
'2001-07-23'
]
};何で1つ目のエントリしか読まないんだ? バグ?
? [ New York Yankees, Atlanta Braves ] : [ 2001-07-02, 2001-08-12, 2001-08-14 ] ? [ Detroit Tigers, Chicago cubs ] : [ 2001-07-23 ]
順番入れ替えたらちゃんと二つ出たぞ。バグっぽいなあ。
##### yaml #####
---
ARRAY(0x1037acb8):
- 2001-07-02
- 2001-08-12
- 2001-08-14
ARRAY(0x103851ac):
- 2001-07-23
##### data #####
$VAR1 = {
'ARRAY(0x103851ac)' => [
'2001-07-23'
],
'ARRAY(0x1037acb8)' => [
'2001-07-02',
'2001-08-12',
'2001-08-14'
]
};Example 2.12. In-Line Nested Mapping
--- # products purchased - item : Super Hoop quantity: 1 - item : Basketball quantity: 4 - item : Big Shoes quantity: 1
##### yaml #####
---
- item: Super Hoop
quantity: 1
- item: Basketball
quantity: 4
- item: Big Shoes
quantity: 1
##### data #####
$VAR1 = [
{
'quantity' => '1',
'item' => 'Super Hoop'
},
{
'quantity' => '4',
'item' => 'Basketball'
},
{
'quantity' => '1',
'item' => 'Big Shoes'
}
];
Scalars
(すべての改行に意味を持つ) Scalar content は litteral style ('|') を使って、block form の中に記述することができる。
各改行を(empty または "more indented" line をのぞいて)空白としておりたたまれる folded style ('>') もある。
Example 2.13. In literals, newlines are preserved
# ASCII Art --- | \//||\/|| // || ||__
##### yaml ##### --- "\\//||\\/||\n// || ||__\n" ##### data ##### $VAR1 = '\\//||\\/|| // || ||__ ';
Example 2.14. In the plain scalar, newlines become spaces
---
Mark McGwire's
year was crippled
by a knee injury.
これも YAmL.pm ではエラーになる。Plain scalar は書けないということか??
YAML Error: Expected separator '---' Code: YAML_PARSE_ERR_NO_SEPARATOR Line: 2 Document: 2
Example 2.15. Folded newlines are preserved for "more indented" and blank lines
> Sammy Sosa completed another fine season with great stats. 63 Home Runs 0.288 Batting Average What a year!
これもそのままだとダメ。アタマをちょっとだけかきかえる。
--- > Sammy Sosa completed another fine season with great stats. 63 Home Runs 0.288 Batting Average What a year!
##### yaml ##### --- | Sammy Sosa completed another fine season with great stats. 63 Home Runs 0.288 Batting Average What a year! ##### data ##### $VAR1 = 'Sammy Sosa completed another fine season with great stats. 63 Home Runs 0.288 Batting Average What a year! ';
Example 2.16. Indentation determines scope
name: Mark McGwire accomplishment: > Mark set a major league home run record in 1998. stats: | 65 Home Runs 0.278 Batting Average
##### yaml #####
---
accomplishment: "Mark set a major league home run record in 1998.\n"
name: Mark McGwire
stats: |
65 Home Runs
0.278 Batting Average
##### data #####
$VAR1 = {
'accomplishment' => 'Mark set a major league home run record in 1998.
',
'stats' => '65 Home Runs
0.278 Batting Average
',
'name' => 'Mark McGwire'
};
YAMLの flow scalars は plain style と quoted styles がある。
Double-quoted style は escape sequences を提供する。
Single-quoted style は escaping が不要なときに便利。
すべての flow scalars は複数行にできる; 改行は常におりたたまれる。
Example 2.17. Quoted Scalars
unicode: "Sosa did fine.\u263A"control: "\b1998\t1999\t2000\n" hexesc: "\x13\x10 is \r\n" single: '"Howdy!" he cried.' quoted: ' # not a ''comment''.' tie-fighter: '|\-*-/|'
##### yaml #####
---
control: "\\b1998\t1999\t2000\n"
hexesc: "\x13\x10 is \r\n"
quoted: " # not a 'comment'."
single: '"Howdy!" he cried.'
tie-fighter: '|\-*-/|'
unicode: Sosa did fine.\u263A
##### data #####
$VAR1 = {
'single' => '"Howdy!" he cried.',
'tie-fighter' => '|\\-*-/|',
'unicode' => 'Sosa did fine.\\u263A',
'quoted' => ' # not a \'comment\'.',
'hexesc' => ' is
',
'control' => '\\b1998 1999 2000
'
};Example 2.18. Multi-line Flow Scalars
plain: This unquoted scalar spans many lines. quoted: "So does this quoted scalar.\n"
これもそのままだと YAML.pm ではエラーになる。複数行の plain scalar はうけつけないのか。
Tags
YAML では、untagged nodes は application に依存した型(type) をあたえる。
一般的な例として、YAML tag repository では "seg", "map", "str" types が使われている。
そのほか、"int", "float", "null", "bool", "set" などもある。
Example 2.19. Integers
canonical: 12345 decimal: +12,345 sexagesimal: 3:25:45 octal: 014 hexadecimal: 0xC
##### yaml #####
---
canonical: 12345
decimal: '+12,345'
hexadecimal: 0xC
octal: 014
sexagesimal: 3:25:45
##### data #####
$VAR1 = {
'octal' => '014',
'sexagesimal' => '3:25:45',
'canonical' => '12345',
'hexadecimal' => '0xC',
'decimal' => '+12,345'
};普通に全部文字列として解釈されているような。
Example 2.20. Floating Point
canonical: 1.23015e+3exponential: 12.3015e+02 sexagesimal: 20:30.15 fixed: 1,230.15 negative infinity: -.inf not a number: .NaN
##### yaml #####
---
canonical: 1.23015e+3
exponential: 12.3015e+02
fixed: '1,230.15'
negative infinity: -.inf
not a number: .NaN
sexagesimal: 20:30.15
##### data #####
$VAR1 = {
'sexagesimal' => '20:30.15',
'canonical' => '1.23015e+3',
'negative infinity' => '-.inf',
'fixed' => '1,230.15',
'not a number' => '.NaN',
'exponential' => '12.3015e+02'
};Example 2.21. Miscellaneous
null: ~ true: y false: n string: '12345'
##### yaml #####
---
false: n
null: ~
string: 12345
true: y
##### data #####
$VAR1 = {
'false' => 'n',
'string' => '12345',
'true' => 'y',
'null' => undef
};Example 2.22. Timestamps
canonical: 2001-12-15T02:59:43.1Z iso8601: 2001-12-14t21:59:43.10-05:00 spaced: 2001-12-14 21:59:43.10 -5 date: 2002-12-14
##### yaml #####
---
canonical: 2001-12-15T02:59:43.1Z
date: 2002-12-14
iso8601: 2001-12-14t21:59:43.10-05:00
spaced: 2001-12-14 21:59:43.10 -5
##### data #####
$VAR1 = {
'canonical' => '2001-12-15T02:59:43.1Z',
'date' => '2002-12-14',
'iso8601' => '2001-12-14t21:59:43.10-05:00',
'spaced' => '2001-12-14 21:59:43.10 -5'
};やっぱり全部普通に文字列になってるよな。
型の明示は exclamation point ('!') を使った tag によってできる。
Global tags は URIs と handle による shorthand で特定されるだろう。
Application-specific local tags も利用できる。
Example 2.23. Various Explicit Tags
--- not-date: !!str 2002-04-28 picture: !!binary | R0lGODlhDAAMAIQAAP//9/X 17unp5WZmZgAAAOfn515eXv Pz7Y6OjuDg4J+fn5OTk6enp 56enmleECcgggoBADs= application specific tag: !something | The semantics of the tag above may be different for different documents.
##### yaml #####
---
application specific tag: |
The semantics of the tag
above may be different for
different documents.
not-date: 2002-04-28
picture: |
R0lGODlhDAAMAIQAAP//9/X
17unp5WZmZgAAAOfn515eXv
Pz7Y6OjuDg4J+fn5OTk6enp
56enmleECcgggoBADs=
##### data #####
$VAR1 = {
'not-date' => '2002-04-28',
'application specific tag' => 'The semantics of the tag
above may be different for
different documents.
',
'picture' => 'R0lGODlhDAAMAIQAAP//9/X
17unp5WZmZgAAAOfn515eXv
Pz7Y6OjuDg4J+fn5OTk6enp
56enmleECcgggoBADs=
'
};Example 2.24. Global Tags
%TAG ! tag:clarkevans.com,2002: --- !shape # Use the ! handle for presenting # tag:clarkevans.com,2002:circle - !circle center: &ORIGIN {x: 73, y: 129} radius: 7 - !line start: *ORIGIN finish: { x: 89, y: 102 } - !label start: *ORIGIN color: 0xFFEEBB text: Pretty vector drawing.
エラーになった。
YAML Error: Can't parse inline implicit value '' Code: YAML_PARSE_ERR_BAD_INLINE_IMPLICIT Line: 1 Document: 1
%TAG という記述そのものが解釈できないのか?
Example 2.25. Unordered Sets
# sets are represented as a # mapping where each key is # associated with the empty string --- !!set ? Mark McGwire ? Sammy Sosa ? Ken Griff
これもエラー。
YAML Error: Invalid element in map Code: YAML_LOAD_ERR_BAD_MAP_ELEMENT Line: 6 Document: 1
Example 2.26. Ordered Mappings
# ordered maps are represented as # a sequence of mappings, with # each mapping having one key --- !!omap - Mark McGwire: 65 - Sammy Sosa: 63 - Ken Griffy: 58
##### yaml #####
--- !!omap
- Mark McGwire: 65
- Sammy Sosa: 63
- Ken Griffy: 58
##### data #####
$VAR1 = [
{
'Mark McGwire' => '65'
},
{
'Sammy Sosa' => '63'
},
{
'Ken Griffy' => '58'
}
];
