Class: ERB

Inherits:
Object
  • Object
show all
Defined in:
lib/erb.rb,
lib/erb.rb,
lib/erb.rb,
lib/erb.rb,
lib/erb.rb

Overview

– ERB::DefMethod

Defined Under Namespace

Modules: DefMethod, Util Classes: Compiler

Constant Summary collapse

Revision =

‘

'$Date$'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(str, safe_level = nil, trim_mode = nil, eoutvar = '_erbout') ⇒ ERB

Constructs a new ERB object with the template specified in str.

An ERB object works by building a chunk of Ruby code that will output the completed template when run. If safe_level is set to a non-nil value, ERB code will be run in a separate thread with $SAFE set to the provided level.

If trim_mode is passed a String containing one or more of the following modifiers, ERB will adjust its code generation as listed:

% enables Ruby code processing for lines beginning with % <> omit newline for lines starting with <% and ending in %> > omit newline for lines ending in %>

eoutvar can be used to set the name of the variable ERB will build up its output in. This is useful when you need to run multiple ERB templates through the same binding and/or when you want to control where output ends up. Pass the name of the variable to be used inside a String.

Example

require "erb"

# build data class
class Listings
  PRODUCT = { :name => "Chicken Fried Steak",
              :desc => "A well messages pattie, breaded and fried.",
              :cost => 9.95 }

  attr_reader :product, :price

  def initialize( product = "", price = "" )
    @product = product
    @price = price
  end

  def build
    b = binding
    # create and run templates, filling member data variebles
    ERB.new(<<-'END_PRODUCT'.gsub(/^\s+/, ""), 0, "", "@product").result b
      <%= PRODUCT[:name] %>
      <%= PRODUCT[:desc] %>
    END_PRODUCT
    ERB.new(<<-'END_PRICE'.gsub(/^\s+/, ""), 0, "", "@price").result b
      <%= PRODUCT[:name] %> -- <%= PRODUCT[:cost] %>
      <%= PRODUCT[:desc] %>
    END_PRICE
  end
end

# setup template data
listings = Listings.new
listings.build

puts listings.product + "\n" + listings.price

Generates

Chicken Fried Steak
A well messages pattie, breaded and fried.

Chicken Fried Steak -- 9.95
A well messages pattie, breaded and fried.



687
688
689
690
691
692
693
 
# File 'lib/erb.rb', line 687

def initialize(str, safe_level=nil, trim_mode=nil, eoutvar='_erbout')
  @safe_level = safe_level
  compiler = ERB::Compiler.new(trim_mode)
  set_eoutvar(compiler, eoutvar)
  @src = compiler.compile(str)
  @filename = nil
end

Instance Attribute Details

#filename ⇒ Object

The optional filename argument passed to Kernel#eval when the ERB code is run



700
701
702
 
# File 'lib/erb.rb', line 700

def filename
  @filename
end

#src ⇒ Object (readonly)

The Ruby code generated by ERB



696
697
698
 
# File 'lib/erb.rb', line 696

def src
  @src
end

Class Method Details

.version ⇒ Object

Returns revision information for the erb.rb module.



242
243
244
 
# File 'lib/erb.rb', line 242

def self.version
  "erb.rb [2.0.4 #{ERB::Revision.split[1]}]"
end

Instance Method Details

#def_class(superklass = Object, methodname = 'result') ⇒ Object

:nodoc:



757
758
759
760
761
 
# File 'lib/erb.rb', line 757

def def_class(superklass=Object, methodname='result')  # :nodoc:
  cls = Class.new(superklass)
  def_method(cls, methodname)
  cls
end

#def_method(mod, methodname, fname = '(ERB)') ⇒ Object

:nodoc:



747
748
749
 
# File 'lib/erb.rb', line 747

def def_method(mod, methodname, fname='(ERB)')  # :nodoc:
  mod.module_eval("def #{methodname}\n" + self.src + "\nend\n", fname, 0)
end

#def_module(methodname = 'erb') ⇒ Object

:nodoc:



751
752
753
754
755
 
# File 'lib/erb.rb', line 751

def def_module(methodname='erb')  # :nodoc:
  mod = Module.new
  def_method(mod, methodname)
  mod
end

#result(b = TOPLEVEL_BINDING) ⇒ Object

Executes the generated ERB code to produce a completed template, returning the results of that code. (See ERB#new for details on how this process can be affected by safe_level.)

b accepts a Binding or Proc object which is used to set the context of code evaluation.



735
736
737
738
739
740
741
742
743
744
745
 
# File 'lib/erb.rb', line 735

def result(b=TOPLEVEL_BINDING)
  if @safe_level
    th = Thread.start { 
	$SAFE = @safe_level
	eval(@src, b, (@filename || '(erb)'), 1)
    }
    return th.value
  else
    return eval(@src, b, (@filename || '(erb)'), 1)
  end
end

#run(b = TOPLEVEL_BINDING) ⇒ Object

Generate results and print them. (see ERB#result)



723
724
725
 
# File 'lib/erb.rb', line 723

def run(b=TOPLEVEL_BINDING)
  print self.result(b)
end

#set_eoutvar(compiler, eoutvar = '_erbout') ⇒ Object

Can be used to set eoutvar as described in ERB#new. It’s probably easier to just use the constructor though, since calling this method requires the setup of an ERB compiler object.



707
708
709
710
711
712
713
714
715
716
717
718
719
720
 
# File 'lib/erb.rb', line 707

def set_eoutvar(compiler, eoutvar = '_erbout')
  compiler.put_cmd = "#{eoutvar}.concat"
  compiler.insert_cmd = "#{eoutvar}.concat"

  cmd = []
  cmd.push "#{eoutvar} = ''"
  
  compiler.pre_cmd = cmd

  cmd = []
  cmd.push(eoutvar)

  compiler.post_cmd = cmd
end