Class: Liquid::For

Inherits:
Block show all
Defined in:
lib/liquid/standardtags.rb

Constant Summary collapse

Syntax = 
/(\w+)\s+in\s+(#{AllowedVariableCharacters}+)/

Instance Attribute Summary

Attributes inherited from Tag

#nodelist

Instance Method Summary collapse

Methods inherited from Block

#block_delimiter, #block_name, #create_variable, #end_tag, #parse, #unknown_tag

Methods inherited from Tag

#name, #parse

Constructor Details

#initialize(markup, tokens) ⇒ For

Returns a new instance of For.



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# File 'lib/liquid/standardtags.rb', line 93

def initialize(markup, tokens)
  super

  if markup =~ Syntax
    @variable_name = $1
    @collection_name = $2
    @name = "#{$1}-#{$2}"
    @attributes = {}
    markup.scan(TagAttributes) do |key, value|
      @attributes[key] = value
    end        
  else
    raise SyntaxError.new("Syntax Error in 'for loop' - Valid syntax: for [item] in [collection]")
  end
end

Instance Method Details

#render(context) ⇒ Object 



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# File 'lib/liquid/standardtags.rb', line 109

def render(context)        
  context.registers[:for] ||= Hash.new(0)
  
  collection = context[@collection_name]
  
  return '' if collection.nil? or collection.empty?
  
  range = (0..collection.length)
  
  if @attributes['limit'] or @attributes['offset']
    
    
    offset = 0
    if @attributes['offset'] == 'continue'
      offset = context.registers[:for][@name] 
    else          
      offset = context[@attributes['offset']] || 0
    end
    
    limit  = context[@attributes['limit']]

    range_end = limit ? offset + limit : collection.length
    
    range = (offset..range_end-1)
    
    # Save the range end in the registers so that future calls to 
    # offset:continue have something to pick up
    context.registers[:for][@name] = range_end
  end
          
  result = []
  segment = collection[range]
  return '' if segment.nil?        

  context.stack do 
    length = segment.length
    
    segment.each_with_index do |item, index|
      context[@variable_name] = item
      context['forloop'] = {
        'name'    => @name,
        'length'  => length,
        'index'   => index + 1, 
        'index0'  => index, 
        'rindex'  => length - index,
        'rindex0' => length - index -1,
        'first'   => (index == 0),
        'last'    => (index == length - 1) }
      
      result << render_all(@nodelist, context)
    end
  end
  
  # Store position of last element we rendered. This allows us to do 
  
  result 
end