Class: VORuby::ADQL::AliasSelectionItem

Inherits:

SelectionItem

• Object
• SelectionItem
• VORuby::ADQL::AliasSelectionItem

Defined in:

lib/voruby/adql/adql.rb,
lib/voruby/adql/transforms.rb

Overview

Used to select an expression as a new alias column.

Instance Attribute Summary

• #as ⇒ Object

  Returns the value of attribute as.

• #expression ⇒ Object

  Returns the value of attribute expression.

Class Method Summary

• .from_xml(node) ⇒ Object

Instance Method Summary

• #initialize(expression, as = nil) ⇒ AliasSelectionItem constructor

  A new instance of AliasSelectionItem.

• #to_adqls ⇒ Object
• #to_s ⇒ Object

Constructor Details

#initialize(expression, as = nil) ⇒ AliasSelectionItem

Returns a new instance of AliasSelectionItem.

# File 'lib/voruby/adql/adql.rb', line 726

def initialize(expression, as=nil)
  self.expression = expression
  self.as = as
end

Instance Attribute Details

#as ⇒ Object

Returns the value of attribute as.

# File 'lib/voruby/adql/adql.rb', line 724

def as
  @as
end

#expression ⇒ Object

Returns the value of attribute expression.

# File 'lib/voruby/adql/adql.rb', line 723

def expression
  @expression
end

Class Method Details

.from_xml(node) ⇒ Object

# File 'lib/voruby/adql/adql.rb', line 745

def self.from_xml(node)
 as = node.attributes['As']
 expr_node = REXML::XPath.first(node, 'Expression')
 expr = ScalarExpression.from_xml(expr_node)
 return AliasSelectionItem.new(expr, as)
end

Instance Method Details

#to_adqls ⇒ Object

# File 'lib/voruby/adql/transforms.rb', line 153

def to_adqls
  if self.as
    "#{self.expression.to_adqls} AS #{self.as}"
  else
    self.expression.to_adqls
  end
end

#to_s ⇒ Object

# File 'lib/voruby/adql/adql.rb', line 741

def to_s
  "{expression=#{self.expression},as=#{self.as}}"
end