Class: Arel::Header

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/arel/algebra/header.rb

Instance Method Summary collapse

Constructor Details

#initialize(attrs = []) ⇒ Header

Returns a new instance of Header.



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# File 'lib/arel/algebra/header.rb', line 5

def initialize(attrs = [])
  @attributes = attrs.to_ary
  @names = Hash.new do |h,k|
    h[k] = @attributes.detect { |a| a.named?(k) }
  end
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/arel/algebra/header.rb', line 24

def ==(other)
  to_set == other.to_set
end

#[](key) ⇒ Object 



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# File 'lib/arel/algebra/header.rb', line 17

def [](key)
  case key
  when String, Symbol then find_by_name(key)
  when Attribute      then find_by_attribute(key)
  end
end

#bind(relation) ⇒ Object 



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# File 'lib/arel/algebra/header.rb', line 38

def bind(relation)
  Header.new(map { |a| a.bind(relation) })
end

#each(&block) ⇒ Object 



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# File 'lib/arel/algebra/header.rb', line 12

def each(&block)
  to_ary.each(&block)
  self
end

#index(i) ⇒ Object

TMP



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# File 'lib/arel/algebra/header.rb', line 43

def index(i)
  to_ary.index(i)
end

#to_ary ⇒ Object 



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# File 'lib/arel/algebra/header.rb', line 34

def to_ary
  @attributes
end

#union(other) ⇒ Object Also known as: | 



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# File 'lib/arel/algebra/header.rb', line 28

def union(other)
  new(to_ary | other)
end