Class: Hpreserve::Filters

Inherits:
Object
  • Object
show all
Defined in:
lib/hpreserve/filters.rb

Overview

Acts as a sandbox to run filters in, most everything except the self.parse method was stolen from Liquid’s Strainer class. Almost all the standard class methods (especially instance_eval) are undefined, and respond_to? is modified to only return true on methods defined by the filter modules registered.

Constant Summary collapse

@@filter_modules = 
[]
@@required_methods = 
%w(__send__ __id__ debugger run inspect methods respond_to? extend)

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.create ⇒ Object 



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# File 'lib/hpreserve/filters.rb', line 20

def self.create
  filterset = Filters.new
  @@filter_modules.each { |m| filterset.extend m }
  filterset
end

.parse(str = '') ⇒ Object

The filter parser expects a string formatted similar to an html element’s “style” attribute:

* <tt>filter="date: %d %b; truncate_words: 15, ...; capitalize"</tt>

(to provide an example of two currently filters you wouldn’t use together…) (todo: better examples fool!). Filters are separated by semicolons and are executed in order given. If the filter needs arguments, those are given after a colon and separated by commas.



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# File 'lib/hpreserve/filters.rb', line 35

def self.parse(str='')
  str.split(';').inject([]) do |memo, rule|
    list = rule.split(':')
    filter = list.shift.strip
    set = [filter]
    unless list.empty?
      list = list.join(':')               # get us back to our original string
      list = list.split(',')              # becase we care about something else
      set += list.collect {|a| a.strip }  # get rid of any pesky whitespace
    end
    memo << set
  end
end

.register(filterset) ⇒ Object 



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# File 'lib/hpreserve/filters.rb', line 13

def self.register(filterset)
  [filterset].flatten.each do |mod|
    raise StandardError("passed filter is not a module") unless mod.is_a?(Module)
    @@filter_modules << mod
  end
end

Instance Method Details

#inspect ⇒ Object

:nodoc keeping inspect around simply to make irb happy.



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# File 'lib/hpreserve/filters.rb', line 53

def inspect; end

#respond_to?(method) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/hpreserve/filters.rb', line 55

def respond_to?(method)
  method_name = method.to_s
  return false if method_name =~ /^__/ 
  return false if @@required_methods.include?(method_name)
  super
end

#run(filter, node, *args) ⇒ Object 



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# File 'lib/hpreserve/filters.rb', line 62

def run(filter, node, *args)
  
  __send__(filter, node, *args) if respond_to?(filter)
end