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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
40年くらいプログラマだよ
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
Complex embedded systems with concurrency and GUI
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Gallstones
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
I wrote them in 1999-2000
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
I wrote them in 1999-2000
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
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Makoto Inoue
Web Developer @ New Bamboo (UK)
Translator of “The dRuby Book”
Rails is A Follower
what we can learn from dRuby’s metaprogramming magic
Masatoshi SEKI
Makoto Inoue
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
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Big Bird.
(scaling twitter)
Rinda
• Shared Queue (TupleSpace)
• Built with DRb
• RingyDingy makes it stupid easy
• See Eric Hodel’s documentation
• O(N) for take(). Sigh.
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
第205回toRubyは2024-06-05
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情報デザインのロゴ
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About me
Masatoshi Seki
Ruby Core Committer (dRuby, Rinda, ERB)
toRuby / Tochigi Ruby Meetup
Pokémon TCG, WCS 2010 Tochigi Pref. winner
RubyKaigi 2022, 2023
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https://www.pokemon-card.com/ex/sv4/
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https://tcg.pokemon.com/en-us/expansions/paradox-rift/
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Agenda
ERB conjecture
Rails-compatible ERB
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Ancient
ERB conjecture
ERB予想
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1999
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Before ERB
When I posted a template engine that replaces &entity;, Shugo told me
about his plans for eRuby.
ruby-dev:5286 (1999-02-19) Re: htmlelem.rb (Re: HTML generator)
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1999
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eRuby specs
ePerlの影響を強くうけているみたいだぞ
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print ≒ <%= .. %> !?
I'm not the one implementing it
(Tsundere)
ePerl! ?
Shugo CEO was a part-time
worker at the time.
1999
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ePerl !?
e is for embedded. 文書にPerlが埋め込まれてる感じみたい
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... !> !?
mod_perl !!!
1999
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I'll write it
embedding control structures 😊
CGI-oriented 😭
CGIに寄せすぎでは？
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1999
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Hello, World.
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Hello, World. print "Hello, World.\n"
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Hello, World.
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<% print "Hello, World!" %> <%= "Hello, World! %>
print "\n" print "Hello, World!" print "Hello, World!" print "
\n"Slide 22
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control structure
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-
<% ENV.each do |row| %>
- <%= row[0] %> <% end %>
- \n"
ENV.each do |row|
print "
- "; print row[0]; print " \n" end print "
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Remember CGI?
$stdout → HTTP response
CGI・おぼえていますか
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puts %Q{Content-Type: text/html}
puts
puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{
- }
ENV.each do |row|
puts %Q!
- #{row[0]} ! end puts %Q{
- TERM_PROGRAM ...
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Remember CGI?
$stdout → HTTP response
CGI・おぼえていますか
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puts %Q{Content-Type: text/html}
puts
puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{
- }
ENV.each do |row|
puts %Q!
- #{row[0]} ! end puts %Q{
- TERM_PROGRAM ...
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Rewrite puts to eRuby
Stringの式展開では制御構造が書きにくい（書ける？）のだがeRubyならかんたん
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puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{}
puts %Q{
- }
ENV.each do |row|
puts %Q!
- #{row[0]} ! end puts %Q{
-
<% ENV.each do |row| %>
- <%= row[0] %> <% end %>
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This specification is not good
CGI programming style will change in the near future
Page generation becomes more complex
Will change to something more server-like
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1999
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becomes more complex
Part of the page will be generated by a method
Helper?
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report hoge
-
<% result.each do |row| %>
- <%= format_date(row.date) %> <% end %>
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becomes more complex
nest
common header, navigation, footer and content
標準出力に出すよりも連結した方がよいのでは？
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ERB conjecture
<%= header %>
<%= navi %>
<%= content %>
<%= footer %>
1999
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CGI programming model will change
A long-lived server is required due to preprocessing costs and
information exchange between requests.
e.g. dRuby + ERB
Concurrency and $stdout will conflict
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ERB conjecture
1999
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ERb and ERbLight
ERb - eRuby's spec, like a command
ERbLight - eRuby w/o $stdout, String concatenation
a library, build the page using String instead of puts()
Support writing Ruby applications using eRuby notation
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1999
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Ruby x 256 book
Legendary hacker explains the power of this specification
2001, ASCII
たださんとartonさんがeRuby/dRubyを絶賛するすごい本
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2001
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renamed ERbLight to ERB
And ERB was included in Ruby's standard library.
ERb is obsolete
ERb is obsolete
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2003
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25 years have passed
almost correct !
ERB-inspired libraries make me happy
Merb, Rails... 自分用のライブラリは自分で書いてるけど、そういうものがあるのはうれしい
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2024
ERB conjecture
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Usage
ERB.new, ERB#result
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>> ERB.new('Hello World').result
=> "Hello World"
>> ERB.new('1 + 1 = <%= 1 + 1 %>').result
=> "1 + 1 = 2"
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ERB#src
Translate eRuby to Ruby
_erboutという変数に結果を連結する
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-
<% list.each do |row| %>
- <%= row %> <% end %>
- \n".freeze
; list.each do |row| ; _erbout.<< "\n
- ".freeze ; _erbout.<<(( row ).to_s); _erbout.<< " \n".freeze ; end ; _erbout.<< "\n
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ERB#result with binding
binding
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-
<% list.each do |row| %>
- <%= row %> <% end %>
- \n\n
- 1 li>\n\n
- two \n\n
- 3.0 li>\n\n
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ERB#def_method
def_method(mod, methodname, fname='(ERB)')
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class Foo
def initialize(arg)
@list = arg
end
ERB.new(<
<% @list.each do |row| %>
<%= row %>
<% end %>
EOS
end
Foo#bar
instance var
unpopular features
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ERB#def_method
Avoid parsing the source multiple times
Compose with small template objects
Used only in Ikezawa's products
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unpopular features
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Proc in template
Case study: Create a survey page with similar questions repeatedly
Each question has a large table with an answer column
Element IDs and form names must be unique
Write in one template
↑矢板市北部で一番Herokuを使ってる「情報デザイン」のロゴ
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Q
A
Q
A
Q
A
Q
A
Q
A
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Actual survey page
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Each question has an answer sheet... !?
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Each cell has detailed answer tables
10MB HTML
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Proc in template
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<% t = Proc.new do |arg| %>
Answer column for <%= arg %>
... <% end %>Question 1
this is the first question <% t.call("q1") %>Question 2
That's the second question <% t.call("q2") %>Question 1
this is the first questionAnswer column for q1
...Question 2
That's the second questionAnswer column for q2
... callSlide 44
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Proc in template
いやなことを思い出した
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<% t = Proc.new do |arg| %>
Answer column for <%= arg %>
... <% end %>Question 1
this is the first question <% t.call("q1") %>Question 2
That's the second question <% t.call("q2") %>Question 1
this is the first questionAnswer column for q1
...Question 2
That's the second questionAnswer column for q2
... callSlide 45
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Future
Rails-compatible ERB
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RubyConf 2014
https://speakerdeck.com/a_matsuda/template-engines-in-ruby
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2014
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I tried
やりましょう
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I noticed this 2 years ago,
!
And asked Seki-san if we could
extend ERB to be "Rails
compatible" before Ruby 2.0
release
2012
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and gave up
できませんでした
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But gave up.
!
Because he didn't like this part in ActionView + Erubis
!
BLOCK_EXPR = /\s+(do|\{)(\s*\|[^|]*\|)?\s*\Z/
!
This code scans the template with the Regexp and
detects the Ruby block, but this kind of code could be
imperfect
!
So this is not acceptable as an ERB spec, said Seki-
san.
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Railsに正規表現でブロックの開始を検知して処理を切り替えるコードがあった
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That is why this syntax is
not acceptable in ERB
<%= form_for @article do |f| %>
...
<% end %>
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Maybe it's solved
I noticed this while writing the slides for RWC2023.
https://gist.github.com/seki/610a42932a85209aaa33547ae983bbdf
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2023
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<%= ... %>
to_s
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<%= 1i ** 0.5 %>
#coding:UTF-8
_erbout = +''; _erbout.<<(( 1i ** 0.5 ).to_s); _erbout.<< "\n".freeze
; _erbout
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<%= ... %> with block
ブロック付きメソッドを <%= ... %>に置くのが難しい
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<%= form_with do %>
...
<% end %>
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<%= ... %> with block
こうなっちゃう
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<%= form_with do %>
...
<% end %>
#coding:UTF-8
_erbout = +''; _erbout.<<(( form_with do ).to_s); _erbout.<< "\n ...
\n".freeze
; end ; _erbout.<< "\n".freeze
; _erbout
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(( ... ).to_s)
((...).to_s)の括弧がじゃまなのでバッファクラスへ移動すればよい？
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<%= form_with do %>
...
<% end %>
#coding:UTF-8
_erbout = +''; _erbout.<<(( form_with do ).to_s); _erbout.<< "\n ...
\n".freeze
; end ; _erbout.<< "\n".freeze
; _erbout
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Customizable
Rubyへの変換方法はカスタマイズできる
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<%= form_with do %>
...
<% end %>
#coding:UTF-8
_erbout = +''; _erbout.<<(( form_with do ).to_s); _erbout.<< "\n ...
\n".freeze
; end ; _erbout.<< "\n".freeze
; _erbout
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Ruby is difficult
Rubyむずかしい
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_erbout << h("str") # OK
_erbout << h "str" # SyntaxError
<<と括弧なし
のメソッド呼び
出し
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Ruby is difficult
Rubyむずかしい
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_erbout << h("str") # OK
_erbout << h "str" # SyntaxError
_erbout.concat h "str" # OK but ....
_erbout.concat form_with "arg" do |arg| # NG
... #
end # concatʹϒϩοΫ͕Δ
<<と括弧なし
のメソッド呼び
出し
<<でなくふつうのメソッド呼び出しにしても
このブロックはconcatのブロック引数になる
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Ruby is difficult
Rubyむずかしい
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_erbout << h("str") # OK
_erbout << h "str" # SyntaxError
_erbout = h "str" #
_erbout = form_with "arg" do |arg| #
...
end
_erbout.concat h "str" # OK but ....
_erbout.concat form_with "arg" do |arg| # NG
... #
end # concatʹϒϩοΫ͕Δ
代入なら大丈夫なのに...
<<と括弧なし
のメソッド呼び
出し
<<でなくふつうのメソッド呼び出しにしても
このブロックはconcatのブロック引数になる
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Addition Asignment
+= works fine
代入しながらメソッド呼べばよい?
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_erbout += h "str" # OK
_erbout += form_with "arg" do |arg| # OK
...
end
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ERBOut
result buffer
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class ERBOut
Buffer = String # SafeBuffer if rails
def initialize(s='')
@str = Buffer.new(s)
end
def to_s
@str
end
def <<(other)
@str << other
end
def +(other)
@str << other.to_s
self
end
def capture(*arg, &block)
save = @str
@str = Buffer.new
yield(*arg)
return @str
ensure
@str = save
end
end
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ERBOut
result buffer
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class ERBOut
Buffer = String # SafeBuffer if rails
def initialize(s='')
@str = Buffer.new(s)
end
def to_s
@str
end
def <<(other)
@str << other
end
def +(other)
@str << other.to_s
self
end
def capture(*arg, &block)
save = @str
@str = Buffer.new
yield(*arg)
return @str
ensure
@str = save
end
end
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ERBOut
result buffer
many tricks
+
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class ERBOut
Buffer = String # SafeBuffer if rails
def initialize(s='')
@str = Buffer.new(s)
end
def to_s
@str
end
def <<(other)
@str << other
end
def +(other)
@str << other.to_s
self
end
def capture(*arg, &block)
save = @str
@str = Buffer.new
yield(*arg)
return @str
ensure
@str = save
end
end
normalize and
concatenate
return itself
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ERBOut
result buffer
many tricks
+
capture
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class ERBOut
Buffer = String # SafeBuffer if rails
def initialize(s='')
@str = Buffer.new(s)
end
def to_s
@str
end
def <<(other)
@str << other
end
def +(other)
@str << other.to_s
self
end
def capture(*arg, &block)
save = @str
@str = Buffer.new
yield(*arg)
return @str
ensure
@str = save
end
end
save
restore
call block and
capture
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なんかできちゃった
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<%= form_with do %>
...
<% end %>
#coding:UTF-8
_erbout = ERB::ERBOut.new; _erbout += form_with do ; _erbout <<
"\n ...\n".freeze
; end ; _erbout << "\n".freeze
; _erbout.to_s
result buffer
addition assignment
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capture
ブロックのローカル変数をさわってcaptureのしかけを呼び出す
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def capture(*arg, &block)
block.binding.local_variable_get(:_erbout).capture(*arg, &block)
end
<% it = capture do %>
...
<% end %>
このブロックのbinding
local var :_erbout of block
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I want someone to make it work in a Rails environment.
I made no progress since last year
進捗ダメです
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Agenda
ERB conjecture
Rails-compatible ERB
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One more thing ...
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One more thing ...
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