class WillPaginate::ViewHelpers::LinkRendererBase

links. It is used by will_paginate helper internally.
This class does the heavy lifting of actually building the pagination

def current_page 

def current_page
  @collection.current_page
end

def pagination 

def pagination
  items = @options[:page_links] ? windowed_page_numbers : []
  items.unshift :previous_page
  items.push :next_page
end

def prepare(collection, options)

* +options+ are forwarded from +will_paginate+ view helper
that conforms to that API
* +collection+ is a WillPaginate::Collection instance or any other object 
def prepare(collection, options)
  @collection = collection
  @options    = options
  # reset values in case we're re-using this instance
  @total_pages = nil
end

def total_pages 

def total_pages
  @total_pages ||= @collection.total_pages
end

def windowed_page_numbers

:outer_window options.
Calculates visible page numbers using the :inner_window and 
def windowed_page_numbers
  inner_window, outer_window = @options[:inner_window].to_i, @options[:outer_window].to_i
  window_from = current_page - inner_window
  window_to = current_page + inner_window
  
  # adjust lower or upper limit if either is out of bounds
  if window_to > total_pages
    window_from -= window_to - total_pages
    window_to = total_pages
  end
  if window_from < 1
    window_to += 1 - window_from
    window_from = 1
    window_to = total_pages if window_to > total_pages
  end
  
  # these are always visible
  middle = window_from..window_to
  # left window
  if outer_window + 3 < middle.first # there's a gap
    left = (1..(outer_window + 1)).to_a
    left << :gap
  else # runs into visible pages
    left = 1...middle.first
  end
  # right window
  if total_pages - outer_window - 2 > middle.last # again, gap
    right = ((total_pages - outer_window)..total_pages).to_a
    right.unshift :gap
  else # runs into visible pages
    right = (middle.last + 1)..total_pages
  end
  
  left.to_a + middle.to_a + right.to_a
end