RubyKaigi2009
Erubis
makoto kuwata <kwa@kuwata-lab.com>
http://www.kuwata-lab.com/
copyright(c) 2009 kuwata-lab.com all rights reserved.
1

‣
‣
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2

Agenda
‣ Part 1. Erubis
‣ Part 2. eRuby
‣ Part 3.
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3

Part 1. Erubis
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4

Erubis
‣ pure Ruby eRuby
‣
• http://jp.rubyist.net/magazine/?0022-FasterThanC
‣
• HTML
•
• PHP, Java, JS, C, Perl, Scheme
• ...
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5

Ruby program:
require 'rubygems' #
require 'erubis'
str = File.read('template.eruby')
eruby = Erubis::Eruby.new(str)
print eruby.result(binding())
command-line:
$ erubis template.eruby #
$ erubis -x template.eruby # Ruby
$ erubis -z template.eruby #
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HTML
str =<<END <%= %>
<%= var %> <%== %>
<%== var %>
END
eruby = Erubis::Eruby.new(str, :escape=>true)
puts eruby.result(:var=>"<B&B>")
output:
&lt;B&am;&gt;
<B&B>
(choosability)
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7

‣ <% %> [% %]
[% for x in @list %]
<li>[%= x %]</li>
[% end %] !
## Ruby
Erubis::Eruby.new(str, :pattern=>'[% %]')
## command-line
$ erubis -p '[% %]' file.eruby
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8

Binding Hash Object
Hash Object
hash = { @title = "Example"
:title => "Example", @items = [1, 2, 3]
:items => [1, 2, 3], } erubis =
erubis = Erubis::Eruby.new(str)
Erubis::Eruby.new(str) puts erubis.evaluate(self)
puts erubis.result(hash)
<h1><%= title%></h1> <h1><%= @title%></h1>
<% for x in items %> <% for x in @items %>
<% end %> <% end %>
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9

Enhancer
‣ Erubis module
## <%= %> HTML
module EscapeEnhancer
def add_expr(src, code, indicator)
if indicator == '='
src << " _buf<<escapeXml(#{code})"
elsif indicator == '=='
src << " _buf<<(#{code}).to_s;"
end
end Erubis
end
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10

Enhancer (cont')
### Enhancer
### ( : print() )
module StdoutEnhancer _buf=""
def add_preamble(src) _buf=$stdout
src << "_buf = $stdout;"
end
def add_postamble(src)
src << "n""n"
end _buf.to_s
end "" ( )
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11

Enhancer
include/extend
### Ruby
class MyEruby < Erubis::Eruby
include Erubis::EscapeEnhancer
include Erubis::PercentLineEnhancer
end
puts MyEruby.new(str).result(:items=>[1,2,3])
,
### command-line
$ erubis -E Escape,Percent file.eruby
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12

Enhancer
‣ EscapeEnhancer : HTML
‣ PercentLineEnhancer : '%'
‣ InterporationEnhancer : _buf<<"#{ }"
‣ DeleteIndentEnhancer : HTML
‣ StdoutEnhancer : _buf="" _buf=$stdout
‣ ... (erubis -h )
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13

‣ (
)
### command-line
$ erubis -c '{arr: [A, B, C]}' template.eruby # YAML
$ erubis -c '@arr=%w[A B C]' template.eruby # Ruby
<% for x in @arr %> <li>A</li>
<li><%= x %></li> <li>B</li>
<% end %> <li>C</li>
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‣ *.yaml *.rb
$ erubis -f data.yaml template.eruby # YAML
$ erubis -f data.rb template.eruby # Ruby
data.yaml data.rb
title: Example @title = "Example"
items: @items =
- name: Foo [ {"name"=>"Foo"},
- name: Bar {"name"=>"Bar"}, ]
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15

‣ <%=== %>
<%=== @var %> 2
### Ruby
$stderr.puts("*** debug: @var=#{@var.inspect}")
###
*** debug: @var=["A", "B", "C"]
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‣ PHP, Java, JS, C, Perl,Scheme ( )
<% for (i=0; i<n; i++) { %> (C )
<li><%= "%d", i %> printf()
<% } %>
#line 1 "file.ec" (erubis -xl c file.ec )
for (i=0; i<n; i++) {
fputs("<li>", stdout); fprintf(stdout, "%d", i);
fputs("n", stdout); }
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17

‣ Erubis
• HTML
•
• Enhancer
• /
•
• PHP, Java, JS, C, Perl, Scheme
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18

Part 2. eRuby
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‣ binding()
•
i=0 ### file.erb
str = File.read('file.erb') <% for i in 1..3 %>
ERB.new(str).result(binding) <li><%= i %></li>
p i #=> 3 <% end %>
!
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20

‣ binding()
•
•
b = Bingind.new
b[:title] = "Example" …
b[:items] = [1, 2, 3]
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ERB
‣( )
‣ Struct
• http://d.hatena.ne.jp/m_seki/20080528/1211909590
Foo = Struct.new(:title, :items)
class Foo
def env; binding(); end
end
ctx = Foo.new("Example", [1,2,3])
ERB.new(str).result(ctx.env)
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22

Erubis
‣ Binding Hash
erubis.result(:items=>[1, 2, 3])
def result(b=TOPLEVEL_BINDING)
if b.is_a?(Hash)
s = b.collect{|k,v| "#{k}=b[#{k.inspect}];"}.join
b = binding()
eval s, b Binding
end
return eval(@src, b)
end
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23

Erubis
‣ Binding Object
@items = [1, 2, 3]; <% for x in @items %>
erubis.evaluate(self) <% end %>
def evaluate(ctx) Hash
if ctx.is_a?(Hash)
hash = ctx; ctx = Object.new
hash.each {|k,v|
ctx.instance_variable_set("@#{k}", v) }
end
return ctx.instance_eval(@src)
end copyright(c) 2009 kuwata-lab.com all rights reserved.
24

ERB
1. 8.6 Erubis::Eruby
ERB
1. 8.7 Erubis::Eruby
ERB
1.9.1 Erubis::Eruby
0 10 20 30
(sec)
(by eval)
(eRuby→Ruby)
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25

ERB
‣
‣
•
class Foo
extend ERB::DefMethod
def_erb_method('render', 'template.erb')
end
print Foo.new.render
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26

Erubis
‣
• Ruby *.cache
•2 *.cache
eruby = Erubis::Eruby.load_file("file.eruby")
print eruby.result()
CGI
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27

Erubis
‣ Proc
•
•
instance_eval
def evaluate(ctx) Proc
@proc ||= eval(@src)
ctx.instance_eval(@proc)
end
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28

‣
• HTML
<ul>
<ul>
<% for x in @list %> <li>AAA</li>
<li><%= x %></li>
<% end %> <li>BBB</li>
</ul>
</ul>
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29

ERB
‣ trim mode
• ">" : "%>"
• "<>" : "<%" "%>"
• "-" : "<%-" "-%>"
• "%" : "%"
• "%>", "%<>", "-" : "%" ">"/"<>"/"-"
ERB.new(str, nil, "%<>")
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30

Erubis
‣
• <% %>
• <%= %>
<ul> <ul>
<% for x in @list %> AAA
<%= x %> BBB
<% end %> CCC
</ul> </ul>
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31

ERB Erubis
eRuby
× ( )
( )
×
( ) ( )
× ( )
( )
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‣
• [ruby-list:18894] eRuby (?)
‣
• <% %> <%= %>
•
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‣ <%= %> HTML
!
• eRuby HTML
•
‣ ?
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34

ERB
‣( )
‣
•
String
• http://www2a.biglobe.ne.jp/~seki/ruby/erbquote.html
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35

Erubis
‣ Erubis
•
eruby = Erubis::Eruby.new(str, :escape=>true)
# or eruby = Erubis::EscapedEruby.new(str)
puts eruby.evaluate(ctx)
Hi <%= @name %>! #
Hi <%== @name %>! #
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36

<% unless @items.blank? %>
<table>
<tbody>
<% @items.each do |item| %>
<tr class="item" id="item-<%=item.id%>">
<td class="item-id"><%= item.id %></td>
<td class="item-name">
<% if item.url && !item.url.empty? %>
<a href="<%= item.url %>"><%=item.name%></a>
<% else %>
<span><%=item.name%></span>
<% end %>
</td>
</tr> HTML Ruby
<% end %>
</tbody> end
</table> (do end 100 )
<% end %>
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37

ERB
‣ ( erb -x )
$ erb -x foo.eruby
_erbout = ''; unless @items.blank? ;
_erbout.concat "n"
_erbout.concat "<table>n"
_erbout.concat " <tr class="record">n"
$ erb -x foo.eruby | ruby -wc
Syntax OK
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38

Erubis
‣
• -x : Ruby
• -X : HTML
• -N : (number)
• -U : 1 (unique)
• -C : (compact)
• -z :
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39

$ cat foo.eruby
<% unless @items.blank? %>
<table>
<% @items.each_with_index do|x, i| %>
<tr class="record">
<td><%= i +1 %></td>
<td><%=h x %></td>
</tr>
<% end %>
</table>
<% end %>
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40

-x Ruby
$ erubis -x foo.eruby
_buf = ''; unless @items.blank?
_buf << '<table>
'; @items.each_with_index do|x, i|
_buf << ' <tr class="record">
<td>'; _buf << ( i +1 ).to_s; _buf << '</td>
<td>'; _buf << (h x ).to_s; _buf << '</td>
</tr>
'; end
_buf << '</table>
'; end
_buf.to_s
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41

-X
$ erubis -X foo.eruby
_buf = ''; unless @items.blank?
@items.each_with_index do|x, i|
_buf << ( i +1 ).to_s;
_buf << (h x ).to_s;
end
end
_buf.to_s
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42

-N (number)
$ erubis -XN foo.eruby
1: _buf = ''; unless @items.blank?
2:
3: @items.each_with_index do|x, i|
4:
5: _buf << ( i +1 ).to_s;
6: _buf << (h x ).to_s;
7:
8: end
9:
10: end
11: _buf.to_s
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43

-U (uniq)
$ erubis -XNU foo.eruby
1: _buf = ''; unless @items.blank?
3: @items.each_with_index do|x, i|
5: _buf << ( i +1 ).to_s;
6: _buf << (h x ).to_s;
8: end
10: end
11: _buf.to_s
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44

-C (compact)
$ erubis -XNC foo.eruby
1: _buf = ''; unless @items.blank?
3: @items.each_with_index do|x, i|
5: _buf << ( i +1 ).to_s;
6: _buf << (h x ).to_s;
8: end
10: end
11: _buf.to_s
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45

<%= %>
<%= form_for :user do %>
<div>
<%= text_field :name %>
</div>
<% end %> eRuby
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46

<%= %>
<%= 10.times do %>
Hello
<% end %>
!
_buf = "";
_buf << ( 10.times do ).to_s;
_buf << " Hellon";
end
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47

ERB+Rails
‣ (_erbout)
!
form_for()
… _erbout
<% form_for do %> _erbout = ""
Hello form_for do
<% end %> _erbout.concat("Hello")
end
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48

Erubis+Merb
‣ Erubis
<%= form_for do %> @_buf << (form_for do;
Hello @_buf << "Hellon"
<% end =%> end);
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49

‣ eRuby
‣ (kool!)
‣
• @_buf
‣
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50

‣ eRuby
eRuby
•
•
•
•
• HTML
•
•
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51

Part 3.
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52

‣
<ul> print "<ul>n"
<% for x in @a %> for x in @a
<li><%=x%></li> print "<li>#{x}</li>n"
<% end %> end
</ul> print "</u>n"
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53

<ul> s = File.read('foo.eruby')
<li><%=x%></li> e = Erubis::Eruby.new(s)
</ul> puts e.evaluate(:x=>1)
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54

‣ ?
<%#ARGS: items, name='guest' %>
Hello <%= name %>!
<% for x in items %>
<li><%=x%></li>
<% end %>
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55

‣ HTML
•
<html> <html>
<body>
<body> !( )
</body>
<h1><%=@title%></h1> </html>
<ul id="menulist">
<% for x in @items %> <h1><%=@title%></h1>
<li><%=x%></li> <ul id="menulist">
</ul>
<% end %>
</ul> <% for x in @items %>
</body> <li><%= x %></li>
</html> <% end %>
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56

‣ Django
....
{% block pagetitle %}
<h1>{{title}}</h1>
{% endblock %}
.... (method override)
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57

AOP
‣ AOP : Aspect Oriented Programming
• /
<table>
"for x in @a" •HTML
<tr>
<td> "print x"
</tr> •
"end"
</table>
( )
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58

‣ HTML View
• …
‣ HTML String
(http://www.oiwa.jp/~yutaka/tdiary/20051229.html)
• /
• Python str unicode
• HTML+String
• HTML (SQL )
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59

‣
‣
• AOP …
‣
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60

‣
• http://jp.rubyist.net/magazine/?0024-TemplateSystem
‣
• http://jp.rubyist.net/magazine/?0024-TemplateSystem2
‣ Erubis
• http://www.kuwata-lab.com/erubis/
‣
• http://www.kuwata-lab.com/tenjin/
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61

one more thing
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62

Tenjin - template engine replacing eRuby
‣ ERB Erubis
• eRuby
•
‣ Tenjin :
• /
•
- ...
• http://www.kuwata-lab.com/tenjin/
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63

thank you
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