1. My Four
Preferences

2. My Four
Preferences
in my Perl Web practice

5. Architecture and music

11. Danube

14. My Four
Preferences
in my Perl Web practice

15. 1. Parsing URLs with grammar
2. .ini configuration files
3. WWW::Page
4. XSLT

16. 0.
Perl 5.10

17. 1.
Parsing URLs with grammar

18. URL is . . .

19. URL is . . .
a string

20. URL is . . .
a string,
a set of parts

21. URL is . . .
a string,
a set of parts,
a container of parameters

22. Blog URL scheme

23. Blog URL scheme
/

24. Blog URL scheme
/
/message‐uri/

25. Blog URL scheme
/
/message‐uri/
/tag/tag‐name/

26. Blog URL scheme
/
/message‐uri/
/tag/tag‐name/
/post/

27. Blog URL scheme
/
/message‐uri/
/tag/tag‐name/
/post/
/message‐uri/post/

28. Blog URL scheme
/
/message‐uri/
/tag/tag‐name/
/post/
/message‐uri/post/
/message‐uri/comments/

29. How to parse?

30. How to parse?
RewriteRules in .htaccess

31. How to parse?
RewriteRules in .htaccess
^$ /index.pl?page=home

32. How to parse?
RewriteRules in .htaccess
^$ /index.pl?page=home
^post/?$ /post.pl

33. How to parse?
RewriteRules in .htaccess
^$ /index.pl?page=home
^post/?$ /post.pl
^([^/]+)/? /index.pl?page=$1

34. How to parse?
RewriteRules in .htaccess
^$ /index.pl?page=home
^post/?$ /post.pl
^([^/]+)/? /index.pl?page=$1
etc.

35. How to parse?
RewriteRules in .htaccess
Bad: involves programming
outside Perl

36. How to parse?
Regular expressions

37. How to parse?
Regular expressions
given ($uri) {
when (/^/$/) {...}
}

38. How to parse?
Regular expressions
given ($uri) {
when (/^/$/) {...}
when (/^/post/?/) {...}
}

39. How to parse?
Regular expressions
given ($uri) {
when (/^/$/) {...}
when (/^/post/?/) {...}
# (regexes as in .htaccess)
}

40. How to parse?
Regular expressions
Bad: rules are not obvious

41. How to parse?
split builtin

42. How to parse?
split builtin
@parts = split m{/}, $uri;
given (scalar @parts) {
when (1) {...}
when (2) {...}
}

43. How to parse?
split builtin
Bad: boring

44. How to parse?
Grammars

45. How to parse?
Grammars
Cool!

46. How to parse?
Grammars
Cool!
Easy to maintain

47. How to parse?
Grammars
Cool!
Easy to maintain
But might be slow

48. How to parse?
Grammars
Cool!
Easy to maintain
But might be slow . . .
up to 100 times over regexes.

49. Gramars
Parse::RecDescent
today
Perl 6 grammars
tomorrow

50. Gramars
Parse::RecDescent
today
Perl 6 grammars
after Christmas

51. uri : post EOL
| view EOL

52. uri : post EOL
| view EOL
post : post‐message
| post‐comment

53. uri : post EOL
| view EOL
post : post‐message
| post‐comment
view : view‐message
| view‐tag

54. uri : post EOL
| view EOL
post : post‐message
| post‐comment
view : view‐message
| view‐tag
view‐message : ‘/’ word ‘/’

55. uri : post EOL
| view EOL
post : post‐message
| post‐comment
view : view‐message
| view‐tag
view‐message : ‘/’ word ‘/’
view‐tag : ‘/tag/’ word ‘/’

56. uri : post EOL
| view EOL
post : post‐message
| post‐comment
view : view‐message
| view‐tag
view‐message : ‘/’ word ‘/’
view‐tag : ‘/tag/’ word ‘/’
word : /w+/

57. uri : post EOL
| view EOL
post : post‐message
| post‐comment
view : view‐message
| view‐tag
view‐message : ‘/’ word ‘/’
view‐tag : ‘/tag/’ word ‘/’
word : /w+/
post‐message : ‘/post/’

58. uri : post EOL
| view EOL
post : post‐message
| post‐comment
view : view‐message
| view‐tag
view‐message : ‘/’ word ‘/’
view‐tag : ‘/tag/’ word ‘/’
word : /w+/
post‐message : ‘/post/’
post‐comment : view‐message ‘/post/’

59. Actions in grammars

60. uri : post EOL
| view EOL

61. uri : post EOL {
$action = ‘post’;
}
| view EOL

62. uri : post EOL {
$action = ‘post’;
}
| view EOL {
$action = ‘view’;
}

63. view‐message : ‘/’ word ‘/’
view‐tag : ‘/tag/’ word ‘/’

64. view‐message : ‘/’ word ‘/’ {
$msg_sid = $item{word};
}
view‐tag : ‘/tag/’ word ‘/’

65. view‐message : ‘/’ word ‘/’ {
$msg_sid = $item{word};
}
view‐tag : ‘/tag/’ word ‘/’ {
$action = ‘view‐tag’;
$tag = $item{word};
}

66. http://example.com/twincity/
$action = ‘view’;
$msg_sid = ‘twincity’;

67. http://example.com/twincity/
$action = ‘view’;
$msg_sid = ‘twincity’;
http://example.com/tag/workshop/
$action = ‘view‐tag’;
$tag = ‘workshop’;

68. my %uri = (
'/' => {
'type' => 'index',
},
'/alpha/' => {
'type' => 'section',
'sectionUri' => 'alpha',
'sectionPage' => 1,
},
'/beta‐2/34/14/' => {
'type' => 'message',
'sectionUri' => 'beta',
'sectionPage' => 2,
'threadID' => 34,
'threadPage' => 1,
'messageID' => 14,
},
'/‐/' => {
'type' => '404',
});

69. for $uri (keys %uri) {
$parser‐>parse($uri);
cmp_deeply(
$parser‐>{data},
$uri{$uri},
$uri
);
}

70. Grammars are
logical

71. Grammars are
logical,
easy to extend

72. Grammars are
logical,
easy to extend,
cacheable

73. Grammars are
logical,
easy to extend,
cacheable,
easy to test

74. 2.
.ini configuration files

75. Application =
code + configuration

76. Example: blog
number of messages per page

77. #!/usr/bin/perl
my $MSG_PER_PAGE = 10;

78. #!/usr/bin/perl
my $MSG_PER_PAGE = 10;

79. Load configuration
from external file

80. Load configuration
from external non-Perl file

81. <config>
<page_length>10</page_length>
</config>

82. Question:
XML
or
JSON
or
YAML
?

83. Answer:
Windows INI

84. [page]
length=10

85. [section]
page_length=10
[thread]
page_length=10
[obsene]
replacement=***
[preview]
last_posts=31
last_message_length=200

86. global.ini local.ini

87. global.ini local.ini
[page]
length=10
[db] [db]
host=db.int host=localhost
port=3333 port=3306

88. use Config::INI::Access;
config‐>load(quot;conf/config.iniquot;);

89. use Config::INI::Access;
config‐>load(quot;conf/config.iniquot;);
config‐>load(quot;conf/local.iniquot;);

90. use Config::INI::Access;
config‐>load(quot;conf/config.iniquot;);
config‐>load(quot;conf/local.iniquot;);
say config‐>db‐>host;

91. [db]
host=localhost
port=3306
say config‐>db‐>host;

92. 3.
WWW::Page

93. WWW::Page
is a kinda MVC

94. http://example.com/some/page

95. http://example.com/some/page
/www/example.com/some/page/index.xml

96. http://example.com/some/page
/www/example.com/some/page/index.xml
XML

97. http://example.com/some/page
/www/example.com/some/page/index.xml
XML
Perl
XML

98. http://example.com/some/page
/www/example.com/some/page/index.xml
XML
Perl
XML
XSLT
HTML

99. http://example.com/some/page
/www/example.com/some/page/index.xml
XML
Perl
XML
XSLT
HTML
Browser

100. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

101. use WWW::Page;
use encoding 'utf‐8';
my $page = new WWW::Page ({
'xslt‐root' => quot;../data/xslquot;,
});
print $page‐>as_string();

102. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

103. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

104. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
sub Import::Client::keywordList
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

105. package Import::Client;
sub keywordList
{
my ($this, $page, $node, $args) = @_;
my $sth = $dbh‐>prepare(
quot;select keyword, uri from keywordsquot;);
$sth‐>execute();
while (my ($keyword, $uri) = $sth‐>fetchrow_array())
{
my $item =
$page‐>{'xml'}‐>createElement ('item');
$item‐>appendText($keyword);
$item‐>setAttribute('uri', $uri);
$node‐>appendChild($item);
}
return $node;
}

106. package Import::Client;
sub keywordList
{
my ($this, $page, $node, $args) = @_;
my $sth = $dbh‐>prepare(
quot;select keyword, uri from keywordsquot;);
$sth‐>execute();
while (my ($keyword, $uri) = $sth‐>fetchrow_array())
{
my $item =
$page‐>{'xml'}‐>createElement ('item');
$item‐>appendText($keyword);
$item‐>setAttribute('uri', $uri);
$node‐>appendChild($item);
}
return $node;
}

107. package Import::Client;
sub keywordList
{
my ($this, $page, $node, $args) = @_;
my $sth = $dbh‐>prepare(
quot;select keyword, uri from keywordsquot;);
$sth‐>execute();
while (my ($keyword, $uri) = $sth‐>fetchrow_array())
{
my $item =
$page‐>{'xml'}‐>createElement ('item');
$item‐>appendText($keyword);
$item‐>setAttribute('uri', $uri);
$node‐>appendChild($item);
}
return $node;
}

108. package Import::Client;
sub keywordList
{
my ($this, $page, $node, $args) = @_;
my $sth = $dbh‐>prepare(
quot;select keyword, uri from keywordsquot;);
$sth‐>execute();
while (my ($keyword, $uri) = $sth‐>fetchrow_array())
{
my $item =
$page‐>{'xml'}‐>createElement ('item');
$item‐>appendText($keyword);
$item‐>setAttribute('uri', $uri);
$node‐>appendChild($item);
}
return $node;
}

109. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

110. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

111. <keyword‐list>
<item uri=quot;http://perl.org/quot;>Perl</item>
<item uri=quot;http://dev.perl.org/quot;>Perl 6</item>
<item uri=quot;http://bbc.co.uk/quot;>Perl on rails</item>
</keyword‐list>

112. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<keyword‐list> . . . </keyword‐list>
</manifest>
<content>
<month‐calendar> . . . </month‐calendar>
</content>
</page>

113. XML
XSLT
HTML
Browser

114. Possible improvements

115. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<page:keyword‐list remote=quot;host2quot;>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

116. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<page:keyword‐list remote=quot;host2quot;>
</manifest>
<content>
<page:month‐calendar cache=quot;memcachedquot;/>
</content>
</page>

117. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<page:keyword‐list remote=quot;host2quot;>
</manifest>
<content>
<page:month‐calendar cache=quot;xmlquot;/>
</content>
</page>

118. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<page:keyword‐list remote=quot;host2quot;>
</manifest>
<content>
<page:month‐calendar transform=quot;other.xslquot;/>
</content>
</page>

119. 4.
XSLT

120. Not .WHAT XSLT is
but .WHY I use it

121. 4a.
XSLT: divide and power

122. website =
logic + layout

123. website =
Perl-code + HTML

124. website =
Perl-code + XML+XSLT

125. website =
Perl-code + XML+XSLT
Perl programmer XSLT coder

126. website =
Perl-code + XML+XSLT
Perl programmer XSLT coder

127. 4b.
XSLT: multiple languages

128. en.xml
<strings>
<months>
<item>January</item>
<item>February</item>
. . .
<item>December</item>
</months>
</strings>

129. de.xml
<strings>
<months>
<item>Januar</item>
<item>Februar</item>
. . .
<item>Dezember</item>
</months>
</strings>

130. at.xml
<strings>
<months>
<item>Jänner</item>
<item>Februar</item>
. . .
<item>Dezember</item>
</months>
</strings>

131. <xsl:variable name=quot;strquot;>
<xsl:copy‐of select=quot;
document(
concat($lang, ‘.xml’)
)quot;/>
</xsl:variable>

132. <xsl:variable name=quot;strquot;>
<xsl:copy‐of select=quot;
document(
concat($lang, ‘.xml’)
)/stringsquot;/>
</xsl:variable>

133. <date day=quot;7quot; month=quot;11quot; year=quot;2008quot;/>

134. <date day=quot;7quot; month=quot;11quot; year=quot;2008quot;/>
<xsl:value‐of select=quot;@dayquot;/>

135. <date day=quot;7quot; month=quot;11quot; year=quot;2008quot;/>
<xsl:value‐of select=quot;@yearquot;/>

136. <date day=quot;7quot; month=quot;11quot; year=quot;2008quot;/>
<xsl:value‐of
select=quot;$str/months/item[@month]quot;/>

137. 4b.
XSLT: multiple layouts

138. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

139. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;pda/view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

140. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;iphone/view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

141. <?xml version=quot;1.0quot; encoding=quot;UTF‐8quot;?>
<page
import=quot;Import::Clientquot;
transform=quot;rss/view.xslquot;
xmlns:page=quot;urn:www‐pagequot;>
<manifest>
<title>WWW::Page Web‐Site</title>
<locale>en‐gb</locale>
<page:keyword‐list/>
</manifest>
<content>
<page:month‐calendar/>
</content>
</page>

142. website =
Perl-code + XML+XSLT
Perl programmer XSLT coder

143. website =
Perl-code + XML+XSLT
Perl programmer XSLT coder
XSLT coder
XSLT coder
XSLT coder

144. __END__
Andrew Shitov
http://andy.sh | mail@andy.sh