Class: Alf::Engine::Wrap

Inherits:
Object
  • Object
show all
Includes:
Cog
Defined in:
lib/alf/engine/wrap.rb

Overview

Wraps attributes under as a sub-tuple

Constant Summary

Constants included from Cog

Cog::EMPTY_CHILDREN, Cog::EMPTY_OPTIONS

Instance Attribute Summary collapse

Attributes included from Compiler::Cog

#compiler, #expr

Instance Method Summary collapse

Methods included from Cog

#children, #each, #options, #to_s

Methods included from Compiler::Cog

#cog_orders, #orderedby?, #relation_type, #to_ascii_tree, #to_cog, #to_relation

Constructor Details

#initialize(operand, attributes, as, allbut, expr = nil, compiler = nil) ⇒ Wrap

Creates a SetAttr instance



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# File 'lib/alf/engine/wrap.rb', line 22

def initialize(operand, attributes, as, allbut, expr = nil, compiler = nil)
  super(expr, compiler)
  @operand = operand
  @attributes = attributes
  @as = as
  @allbut = allbut
end

Instance Attribute Details

#allbut ⇒ Boolean (readonly)

Returns Allbut wrapping?.

Returns:

  • (Boolean) —

    Allbut wrapping?



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# File 'lib/alf/engine/wrap.rb', line 19

def allbut
  @allbut
end

#as ⇒ AttrName (readonly)

Returns Name of the introduced wrapped attribute.

Returns:

  • (AttrName) —

    Name of the introduced wrapped attribute



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# File 'lib/alf/engine/wrap.rb', line 16

def as
  @as
end

#attributes ⇒ AttrList (readonly)

Returns Attributes to wrap.

Returns:

  • (AttrList) —

    Attributes to wrap



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# File 'lib/alf/engine/wrap.rb', line 13

def attributes
  @attributes
end

#operand ⇒ Enumerable (readonly)

Returns The operand.

Returns:

  • (Enumerable) —

    The operand



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# File 'lib/alf/engine/wrap.rb', line 10

def operand
  @operand
end

Instance Method Details

#_each ⇒ Object 



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# File 'lib/alf/engine/wrap.rb', line 31

def _each
  operand.each do |tuple|
    rest, key = @attributes.split_tuple(tuple, @allbut)
    key[@as] = rest
    yield key
  end
end

#arguments ⇒ Object 



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# File 'lib/alf/engine/wrap.rb', line 39

def arguments
  [ attribute ]
end