Class: Keisan::AST::Plus

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

Methods inherited from Parent

#==, #deep_dup, #freeze, #is_constant?, #replace, #traverse, #unbound_functions, #unbound_variables

Methods inherited from Node

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

Constructor Details

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

Returns a new instance of Plus.



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

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

Class Method Details

.symbol ⇒ Object 



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

def self.symbol
  :+
end

Instance Method Details

#blank_value ⇒ Object 



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

def blank_value
  0
end

#differentiate(variable, context = nil) ⇒ Object 



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# File 'lib/keisan/ast/plus.rb', line 78

def differentiate(variable, context = nil)
  Plus.new(children.map {|child| child.differentiate(variable, context)}).simplify(context)
end

#evaluate(context = nil) ⇒ Object 



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# File 'lib/keisan/ast/plus.rb', line 34

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/plus.rb', line 38

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

  super(context)

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

  if children.all? {|child| child.is_a?(String)}
    return String.new(children.inject("") do |result, child|
      result + child.value
    end)
  elsif children.all? {|child| child.is_a?(List)}
    return List.new(children.inject([]) do |result, child|
      result + child.value
    end)
  end

  constants, non_constants = *children.partition {|child| child.is_a?(Number)}
  constant = constants.inject(Number.new(0), &:+).simplify(context)

  if non_constants.empty?
    constant
  else
    @children = constant.value(context) == 0 ? [] : [constant]
    @children += non_constants

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

    self
  end
end

#value(context = nil) ⇒ Object 



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

def value(context = nil)
  children_values = children.map {|child| child.value(context)}
  # Special case of string concatenation
  if children_values.all? {|child| child.is_a?(::String)}
    children_values.join
  # Special case of array concatenation
  elsif children_values.all? {|child| child.is_a?(::Array)}
    children_values.inject([], &:+)
  elsif children_values.one? {|child| child.is_a?(::Date)}
    date_time_plus(children_values, ::Date)
  elsif children_values.one? {|child| child.is_a?(::Time)}
    date_time_plus(children_values, ::Time)
  else
    children_values.inject(0, &:+)
  end.to_node.value(context)
end