57 lines
1.2 KiB
Ruby
57 lines
1.2 KiB
Ruby
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# frozen_string_literal: true
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# This module handles element positions in a list.
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module Sidebars
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module Concerns
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module PositionableList
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def add_element(list, element)
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return unless element
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list << element
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end
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def insert_element_before(list, before_element, new_element)
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return unless new_element
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index = index_of(list, before_element)
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if index
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list.insert(index, new_element)
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else
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list.unshift(new_element)
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end
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end
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def insert_element_after(list, after_element, new_element)
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return unless new_element
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index = index_of(list, after_element)
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if index
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list.insert(index + 1, new_element)
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else
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add_element(list, new_element)
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end
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end
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def replace_element(list, element_to_replace, new_element)
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return unless new_element
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index = index_of(list, element_to_replace)
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return unless index
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list[index] = new_element
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end
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private
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# Classes including this method will have to define
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# the way to identify elements through this method
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def index_of(list, element)
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raise NotImplementedError
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end
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end
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end
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end
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