Class: Keisan::AST::Times

Inherits:
ArithmeticOperator show all
Defined in:
lib/keisan/ast/times.rb

Constant Summary

Constants inherited from Operator

Operator::ARITIES, Operator::ARITY_PRIORITY_ASSOCIATIVITY, Operator::ASSOCIATIVITIES, Operator::ASSOCIATIVITY_OF_PRIORITY, Operator::PRIORITIES

Instance Attribute Summary

Attributes inherited from Parent

#children

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Operator

#arity, arity, associativity, #associativity, associativity_of_priority, #evaluate_assignments, #priority, priority, #symbol, #to_s, #value

Methods inherited from Parent

#==, #deep_dup, #freeze, #replace, #unbound_functions, #unbound_variables

Methods inherited from Node

#!, #%, #&, #*, #**, #+, #+@, #-, #-@, #/, #<, #<=, #>, #>=, #^, #and, #coerce, #deep_dup, #equal, #evaluate_assignments, #evaluated, #false?, #not_equal, #or, #replace, #simplified, #to_cell, #to_node, #true?, #unbound_functions, #unbound_variables, #value, #well_defined?, #|, #~

Constructor Details

#initialize(children = [], parsing_operators = []) ⇒ Times

Returns a new instance of Times.



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# File 'lib/keisan/ast/times.rb', line 4

def initialize(children = [], parsing_operators = [])
  super
  convert_divide_to_inverse!
end

Class Method Details

.symbol ⇒ Object 



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# File 'lib/keisan/ast/times.rb', line 9

def self.symbol
  :*
end

Instance Method Details

#blank_value ⇒ Object 



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# File 'lib/keisan/ast/times.rb', line 13

def blank_value
  1
end

#differentiate(variable, context = nil) ⇒ Object 



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# File 'lib/keisan/ast/times.rb', line 53

def differentiate(variable, context = nil)
  # Product rule
  Plus.new(
    children.map.with_index do |child,i|
      Times.new(
        children.slice(0,i) + [child.differentiate(variable, context)] + children.slice(i+1,children.size)
      )
    end
  ).simplify(context)
end

#evaluate(context = nil) ⇒ Object 



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# File 'lib/keisan/ast/times.rb', line 17

def evaluate(context = nil)
  children[1..-1].inject(children.first.evaluate(context)) {|total, child| total * child.evaluate(context)}
end

#simplify(context = nil) ⇒ Object 



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# File 'lib/keisan/ast/times.rb', line 21

def simplify(context = nil)
  context ||= Context.new

  super(context)

  # Commutative, so pull in operands of any `Times` operators
  @children = children.inject([]) do |new_children, cur_child|
    case cur_child
    when Times
      new_children + cur_child.children
    else
      new_children << cur_child
    end
  end

  constants, non_constants = *children.partition {|child| child.is_a?(Number)}
  constant = constants.inject(Number.new(1), &:*).simplify(context)

  return Number.new(0) if constant.value(context) == 0

  if non_constants.empty?
    constant
  else
    @children = constant.value(context) == 1 ? [] : [constant]
    @children += non_constants

    return @children.first.simplify(context) if @children.size == 1

    self
  end
end