Class: FunctionExpression

Inherits:
Object
  • Object
show all
Defined in:
lib/expressions/function_expression.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(function, arguments) ⇒ FunctionExpression

Returns a new instance of FunctionExpression.



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# File 'lib/expressions/function_expression.rb', line 7

def initialize(function, arguments)
  @function = function
  @arguments = arguments.map { |each| PredicateLiteral.parse(each) }
end

Class Method Details

.parse(array) ⇒ Object 



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# File 'lib/expressions/function_expression.rb', line 3

def self.parse(array)
  self.new(array[1], array[2..-1])
end

Instance Method Details

#build_arel(arel_table) ⇒ Object 



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# File 'lib/expressions/function_expression.rb', line 12

def build_arel(arel_table)
  arguments = @arguments.map { |each| each.build_arel(arel_table) }
  case @function
    # when "sum:"
    when "count:"
      return arguments.first.count()
    # when "min:"
    # when "max:"
    # when "average:"
    when "first:"
      object = @arguments.first.build_arel(arel_table)
      raise "first:(#{object}) not supported by Arel"
      return object

    when "last:"
      object = @arguments.first.build_arel(arel_table)
      raise "last::(#{object}) not supported by Arel"
      return object

    when "fromObject:index:"
      object = @arguments.first.build_arel(arel_table)
      index = @arguments.second.build_arel (arel_table)
      raise "fromObject:(#{object})index:(#{index}) not supported by Arel"
      return object[index]

    when "add:to:"
      return arguments.reduce(:+)

    when "from:substract:"
      return arguments.reduce(:-)

    when "multiply:by:"
      return arguments.reduce(:*)

    when "divide:by:"
      return arguments.reduce(:/)

    # when "sqrt:"

    when "raise:to:"
      return arguments.reduce(:**)

    # when "abs:"
    # when "now:"
    # when "ln:"
    # when "exp:"
    # when "ceiling:"
    # when "random:"
    # when "modulus:by:"
    # when "chs:"

    else
      raise "Unknown function #{@function} #{arguments}"
  end
end