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Курс във Факултета по Математика и Информатика към СУ

Решение на Трета задача от Емил Гоцев

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Към профила на Емил Гоцев

Резултати

  • 6 точки от тестове
  • 0 бонус точки
  • 6 точки общо
  • 13 успешни тест(а)
  • 0 неуспешни тест(а)

Код

class Expr
def self.build(expression)
case expression[0]
when :number then Number.new(expression[1])
when :variable then Variable.new(expression[1])
when :+ then Addition.new(build(expression[1]), build(expression[2]))
when :* then Multiplication.new(build(expression[1]), build(expression[2]))
when :- then Negation.new(build(expression[1]))
when :sin then Sine.new(build(expression[1]))
when :cos then Cosine.new(build(expression[1]))
end
end
def *(other)
if self == Number::ZERO || other == Number::ZERO
Number.new(0)
elsif self == Number::ONE
other
elsif other == Number::ONE
self
else
Multiplication.new(self, other)
end
end
def +(other)
if self == Number::ZERO
other
elsif other == Number::ZERO
self
else
Addition.new(self, other)
end
end
def -@
if self == Number::ZERO
@parameter
else
Negation.new(self)
end
end
end
class Unary < Expr
attr_accessor :parameter
def initialize(parameter)
@parameter = parameter
end
def ==(other)
if other.class == self.class
@parameter == other.parameter
end
end
def exact?
@parameter.exact?
end
end
class Binary < Expr
attr_accessor :parameter1, :parameter2
def initialize(parameter1, parameter2)
@parameter1, @parameter2 = parameter1, parameter2
end
def ==(other)
if other.class == self.class
@parameter1 == other.parameter1 && @parameter2 == other.parameter2
end
end
def exact?
@parameter1.exact? & @parameter2.exact?
end
end
class Number < Unary
ZERO = Number.new(0)
ONE = Number.new(1)
def evaluate(environment = {})
@parameter
end
def simplify
self
end
def exact?
true
end
def derive(variable)
Number.new(0)
end
def to_s
@parameter.to_s
end
end
class Addition < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) + @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify + @parameter2.simplify
end
end
def derive(variable)
(@parameter1.derive(variable) + @parameter2.derive(variable)).simplify
end
def to_s
"(#{@parameter1} + #{@parameter2})"
end
end
class Negation < Unary
def evaluate(environment = {})
-@parameter.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
-@parameter.simplify
end
end
def derive(variable)
(-@parameter.derive(variable)).simplify
end
def to_s
"-#{@parameter}"
end
end
class Multiplication < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) * @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify * @parameter2.simplify
end
end
def derive(variable)
result = @parameter1.derive(variable) * @parameter2 + @parameter1 * @parameter2.derive(variable)
result.simplify
end
def to_s
"(#{@parameter1} * #{@parameter2})"
end
end
class Variable < Unary
def evaluate(environment = {})
environment.values_at(@parameter)[0]
end
def simplify
self
end
def exact?
false
end
def derive(variable)
if variable == @parameter
Number.new(1)
else
Number.new(0)
end
end
def to_s
@parameter.to_s
end
end
class Sine < Unary
def evaluate(environment = {})
Math.sin @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Sine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * Cosine.new(@parameter)).simplify
end
def to_s
"sin(#{@parameter})"
end
end
class Cosine < Unary
def evaluate(environment = {})
Math.cos @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Cosine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * (- Sine.new(@parameter))).simplify
end
def to_s
"cos(#{@parameter})"
end
end

Лог от изпълнението

.............

Finished in 0.05002 seconds
13 examples, 0 failures

История (6 версии и 1 коментар)

Емил обнови решението на 13.11.2012 00:05 (преди почти 13 години)

+class Expr
+ def self.build(expression)
+ case expression[0]
+ when :number then Number.new(expression[1])
+ when :variable then Variable.new(expression[1])
+ when :+ then Addition.new(build(expression[1]), build(expression[2]))
+ when :* then Multiplication.new(build(expression[1]), build(expression[2]))
+ when :- then Negation.new(build(expression[1]))
+ when :sin then Sine.new(build(expression[1]))
+ when :cos then Cosine.new(build(expression[1]))
+ end
+ end
+
+ def *(other)
+ if self == Zero || other == Zero
+ Number.new(0)
+ elsif self == One
+ other
+ elsif other == One
+ self
+ else
+ Multiplication.new(self, other)
+ end
+ end
+
+ def +(other)
+ if self == Zero
+ other
+ elsif other == Zero
+ self
+ else
+ Addition.new(self, other)
+ end
+ end
+
+ def -@
+ if self == Zero
+ @parameter
+ else
+ Negation.new(self)
+ end
+ end
+end
+
+class Unary < Expr
+ attr_accessor :parameter
+
+ def initialize(parameter)
+ @parameter = parameter
+ end
+
+ def ==(other)
+ @parameter == other.parameter
+ end
+
+ def exact?
+ @parameter.exact?
+ end
+end
+
+class Binary < Expr
+ attr_accessor :parameter1, :parameter2
+
+ def initialize(parameter1, parameter2)
+ @parameter1, @parameter2 = parameter1, parameter2
+ end
+
+ def ==(other)
+ @parameter1 == other.parameter1 && @parameter2 == other.parameter2
+ end
+
+ def exact?
+ @parameter1.exact? & @parameter2.exact?
+ end
+end
+
+class Number < Unary
+ def evaluate(environment = {})
+ @parameter
+ end
+
+ def simplify
+ self
+ end
+
+ def exact?
+ true
+ end
+
+ def derive(variable)
+ Number.new(0)
+ end
+end
+
+class Addition < Binary
+ def evaluate(environment = {})
+ @parameter1.evaluate(environment) + @parameter2.evaluate(environment)
+ end
+
+ def simplify
+ if exact?
+ Number.new(evaluate)
+ else
+ @parameter1.simplify + @parameter2.simplify
+ end
+ end
+
+ def derive(variable)
+ (@parameter1.derive(variable) + @parameter2.derive(variable)).simplify
+ end
+end
+
+class Negation < Unary
+ def evaluate(environment = {})
+ -@parameter.evaluate(environment)
+ end
+
+ def simplify
+ if exact?
+ Number.new(evaluate)
+ else
+ -@parameter.simplify
+ end
+ end
+
+ def derive(variable)
+ (-@parameter.derive(variable)).simplify
+ end
+end
+
+class Multiplication < Binary
+ def evaluate(environment = {})
+ @parameter1.evaluate(environment) * @parameter2.evaluate(environment)
+ end
+
+ def simplify
+ if exact?
+ Number.new(evaluate)
+ else
+ @parameter1.simplify * @parameter2.simplify
+ end
+ end
+
+ def derive(variable)
+ result = @parameter1.derive(variable) * @parameter2 + @parameter1 * @parameter2.derive(variable)
+ result.simplify
+ end
+end
+
+class Variable < Unary
+ def evaluate(environment = {})
+ environment.values_at(@parameter)[0]
+ end
+
+ def simplify
+ self
+ end
+
+ def exact?
+ false
+ end
+
+ def derive(variable)
+ if variable == @parameter
+ Number.new(1)
+ else
+ Number.new(0)
+ end
+ end
+end
+
+class Sine < Unary
+ def evaluate(environment = {})
+ Math.sin @parameter.evaluate(environment)
+ end
+
+ def simplify
+ if @parameter.exact?
+ Number.new(evaluate)
+ else
+ Sine.new(@parameter.simplify)
+ end
+ end
+
+ def derive(variable)
+ (@parameter.derive(variable) * Cosine.new(@parameter)).simplify
+ end
+end
+
+class Cosine < Unary
+ def evaluate(environment = {})
+ Math.cos @parameter.evaluate(environment)
+ end
+
+ def simplify
+ if @parameter.exact?
+ Number.new(evaluate)
+ else
+ Cosine.new(@parameter.simplify)
+ end
+ end
+
+ def derive(variable)
+ (@parameter.derive(variable) * (- Sine.new(@parameter))).simplify
+ end
+end
+
+Zero = Number.new(0)
+One = Number.new(1)
+
+p Expr.build([:cos, [:variable, :x]]).derive(:x)

Емил обнови решението на 13.11.2012 00:06 (преди почти 13 години)

class Expr
def self.build(expression)
case expression[0]
when :number then Number.new(expression[1])
when :variable then Variable.new(expression[1])
when :+ then Addition.new(build(expression[1]), build(expression[2]))
when :* then Multiplication.new(build(expression[1]), build(expression[2]))
when :- then Negation.new(build(expression[1]))
when :sin then Sine.new(build(expression[1]))
when :cos then Cosine.new(build(expression[1]))
end
end
def *(other)
if self == Zero || other == Zero
Number.new(0)
elsif self == One
other
elsif other == One
self
else
Multiplication.new(self, other)
end
end
def +(other)
if self == Zero
other
elsif other == Zero
self
else
Addition.new(self, other)
end
end
def -@
if self == Zero
@parameter
else
Negation.new(self)
end
end
end
class Unary < Expr
attr_accessor :parameter
def initialize(parameter)
@parameter = parameter
end
def ==(other)
@parameter == other.parameter
end
def exact?
@parameter.exact?
end
end
class Binary < Expr
attr_accessor :parameter1, :parameter2
def initialize(parameter1, parameter2)
@parameter1, @parameter2 = parameter1, parameter2
end
def ==(other)
@parameter1 == other.parameter1 && @parameter2 == other.parameter2
end
def exact?
@parameter1.exact? & @parameter2.exact?
end
end
class Number < Unary
def evaluate(environment = {})
@parameter
end
def simplify
self
end
def exact?
true
end
def derive(variable)
Number.new(0)
end
end
class Addition < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) + @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify + @parameter2.simplify
end
end
def derive(variable)
(@parameter1.derive(variable) + @parameter2.derive(variable)).simplify
end
end
class Negation < Unary
def evaluate(environment = {})
-@parameter.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
-@parameter.simplify
end
end
def derive(variable)
(-@parameter.derive(variable)).simplify
end
end
class Multiplication < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) * @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify * @parameter2.simplify
end
end
def derive(variable)
result = @parameter1.derive(variable) * @parameter2 + @parameter1 * @parameter2.derive(variable)
result.simplify
end
end
class Variable < Unary
def evaluate(environment = {})
environment.values_at(@parameter)[0]
end
def simplify
self
end
def exact?
false
end
def derive(variable)
if variable == @parameter
Number.new(1)
else
Number.new(0)
end
end
end
class Sine < Unary
def evaluate(environment = {})
Math.sin @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Sine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * Cosine.new(@parameter)).simplify
end
end
class Cosine < Unary
def evaluate(environment = {})
Math.cos @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Cosine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * (- Sine.new(@parameter))).simplify
end
end
Zero = Number.new(0)
-One = Number.new(1)
-
+One = Number.new(1)
-p Expr.build([:cos, [:variable, :x]]).derive(:x)

Емил обнови решението на 13.11.2012 00:25 (преди почти 13 години)

class Expr
def self.build(expression)
case expression[0]
when :number then Number.new(expression[1])
when :variable then Variable.new(expression[1])
when :+ then Addition.new(build(expression[1]), build(expression[2]))
when :* then Multiplication.new(build(expression[1]), build(expression[2]))
when :- then Negation.new(build(expression[1]))
when :sin then Sine.new(build(expression[1]))
when :cos then Cosine.new(build(expression[1]))
end
end
def *(other)
if self == Zero || other == Zero
Number.new(0)
elsif self == One
other
elsif other == One
self
else
Multiplication.new(self, other)
end
end
def +(other)
if self == Zero
other
elsif other == Zero
self
else
Addition.new(self, other)
end
end
def -@
if self == Zero
@parameter
else
Negation.new(self)
end
end
end
class Unary < Expr
attr_accessor :parameter
def initialize(parameter)
@parameter = parameter
end
def ==(other)
- @parameter == other.parameter
+ if other.respond_to? :parameter
+ @parameter == other.parameter
+ end
end
def exact?
@parameter.exact?
end
end
class Binary < Expr
attr_accessor :parameter1, :parameter2
def initialize(parameter1, parameter2)
@parameter1, @parameter2 = parameter1, parameter2
end
def ==(other)
- @parameter1 == other.parameter1 && @parameter2 == other.parameter2
+ if other.respond_to?(:parameter1) && other.respond_to?(:parameter2)
+ @parameter1 == other.parameter1 && @parameter2 == other.parameter2
+ end
end
def exact?
@parameter1.exact? & @parameter2.exact?
end
end
class Number < Unary
def evaluate(environment = {})
@parameter
end
def simplify
self
end
def exact?
true
end
def derive(variable)
Number.new(0)
end
end
class Addition < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) + @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify + @parameter2.simplify
end
end
def derive(variable)
(@parameter1.derive(variable) + @parameter2.derive(variable)).simplify
end
end
class Negation < Unary
def evaluate(environment = {})
-@parameter.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
-@parameter.simplify
end
end
def derive(variable)
(-@parameter.derive(variable)).simplify
end
end
class Multiplication < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) * @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify * @parameter2.simplify
end
end
def derive(variable)
result = @parameter1.derive(variable) * @parameter2 + @parameter1 * @parameter2.derive(variable)
result.simplify
end
end
class Variable < Unary
def evaluate(environment = {})
environment.values_at(@parameter)[0]
end
def simplify
self
end
def exact?
false
end
def derive(variable)
if variable == @parameter
Number.new(1)
else
Number.new(0)
end
end
end
class Sine < Unary
def evaluate(environment = {})
Math.sin @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Sine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * Cosine.new(@parameter)).simplify
end
end
class Cosine < Unary
def evaluate(environment = {})
Math.cos @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Cosine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * (- Sine.new(@parameter))).simplify
end
end
Zero = Number.new(0)
-One = Number.new(1)
+One = Number.new(1)
+
+p Expr.build([:cos, [:variable, :x]]).derive(:x)

Емил обнови решението на 13.11.2012 00:25 (преди почти 13 години)

class Expr
def self.build(expression)
case expression[0]
when :number then Number.new(expression[1])
when :variable then Variable.new(expression[1])
when :+ then Addition.new(build(expression[1]), build(expression[2]))
when :* then Multiplication.new(build(expression[1]), build(expression[2]))
when :- then Negation.new(build(expression[1]))
when :sin then Sine.new(build(expression[1]))
when :cos then Cosine.new(build(expression[1]))
end
end
def *(other)
if self == Zero || other == Zero
Number.new(0)
elsif self == One
other
elsif other == One
self
else
Multiplication.new(self, other)
end
end
def +(other)
if self == Zero
other
elsif other == Zero
self
else
Addition.new(self, other)
end
end
def -@
if self == Zero
@parameter
else
Negation.new(self)
end
end
end
class Unary < Expr
attr_accessor :parameter
def initialize(parameter)
@parameter = parameter
end
def ==(other)
if other.respond_to? :parameter
@parameter == other.parameter
end
end
def exact?
@parameter.exact?
end
end
class Binary < Expr
attr_accessor :parameter1, :parameter2
def initialize(parameter1, parameter2)
@parameter1, @parameter2 = parameter1, parameter2
end
def ==(other)
if other.respond_to?(:parameter1) && other.respond_to?(:parameter2)
@parameter1 == other.parameter1 && @parameter2 == other.parameter2
end
end
def exact?
@parameter1.exact? & @parameter2.exact?
end
end
class Number < Unary
def evaluate(environment = {})
@parameter
end
def simplify
self
end
def exact?
true
end
def derive(variable)
Number.new(0)
end
end
class Addition < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) + @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify + @parameter2.simplify
end
end
def derive(variable)
(@parameter1.derive(variable) + @parameter2.derive(variable)).simplify
end
end
class Negation < Unary
def evaluate(environment = {})
-@parameter.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
-@parameter.simplify
end
end
def derive(variable)
(-@parameter.derive(variable)).simplify
end
end
class Multiplication < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) * @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify * @parameter2.simplify
end
end
def derive(variable)
result = @parameter1.derive(variable) * @parameter2 + @parameter1 * @parameter2.derive(variable)
result.simplify
end
end
class Variable < Unary
def evaluate(environment = {})
environment.values_at(@parameter)[0]
end
def simplify
self
end
def exact?
false
end
def derive(variable)
if variable == @parameter
Number.new(1)
else
Number.new(0)
end
end
end
class Sine < Unary
def evaluate(environment = {})
Math.sin @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Sine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * Cosine.new(@parameter)).simplify
end
end
class Cosine < Unary
def evaluate(environment = {})
Math.cos @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Cosine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * (- Sine.new(@parameter))).simplify
end
end
Zero = Number.new(0)
-One = Number.new(1)
-
+One = Number.new(1)
-p Expr.build([:cos, [:variable, :x]]).derive(:x)

Емил обнови решението на 14.11.2012 13:27 (преди почти 13 години)

class Expr
def self.build(expression)
case expression[0]
when :number then Number.new(expression[1])
when :variable then Variable.new(expression[1])
when :+ then Addition.new(build(expression[1]), build(expression[2]))
when :* then Multiplication.new(build(expression[1]), build(expression[2]))
when :- then Negation.new(build(expression[1]))
when :sin then Sine.new(build(expression[1]))
when :cos then Cosine.new(build(expression[1]))
end
end
def *(other)
- if self == Zero || other == Zero
+ if self == Number::ZERO || other == Number::ZERO
Number.new(0)
- elsif self == One
+ elsif self == Number::ONE
other
- elsif other == One
+ elsif other == Number::ONE
self
else
Multiplication.new(self, other)
end
end
def +(other)
- if self == Zero
+ if self == Number::ZERO
other
- elsif other == Zero
+ elsif other == Number::ZERO
self
else
Addition.new(self, other)
end
end
def -@
- if self == Zero
+ if self == Number::ZERO
@parameter
else
Negation.new(self)
end
end
end
class Unary < Expr
attr_accessor :parameter
def initialize(parameter)
@parameter = parameter
end
def ==(other)
- if other.respond_to? :parameter
+ if other.class == self.class
@parameter == other.parameter
end
end
def exact?
@parameter.exact?
end
end
class Binary < Expr
attr_accessor :parameter1, :parameter2
def initialize(parameter1, parameter2)
@parameter1, @parameter2 = parameter1, parameter2
end
def ==(other)
- if other.respond_to?(:parameter1) && other.respond_to?(:parameter2)
+ if other.class == self.class
@parameter1 == other.parameter1 && @parameter2 == other.parameter2
end
end
def exact?
@parameter1.exact? & @parameter2.exact?
end
end
class Number < Unary
+ ZERO = Number.new(0)
+ ONE = Number.new(1)
+
def evaluate(environment = {})
@parameter
end
def simplify
self
end
def exact?
true
end
def derive(variable)
Number.new(0)
end
end
class Addition < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) + @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify + @parameter2.simplify
end
end
def derive(variable)
(@parameter1.derive(variable) + @parameter2.derive(variable)).simplify
end
end
class Negation < Unary
def evaluate(environment = {})
-@parameter.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
-@parameter.simplify
end
end
def derive(variable)
(-@parameter.derive(variable)).simplify
end
end
class Multiplication < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) * @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify * @parameter2.simplify
end
end
def derive(variable)
result = @parameter1.derive(variable) * @parameter2 + @parameter1 * @parameter2.derive(variable)
result.simplify
end
end
class Variable < Unary
def evaluate(environment = {})
environment.values_at(@parameter)[0]
end
def simplify
self
end
def exact?
false
end
def derive(variable)
if variable == @parameter
Number.new(1)
else
Number.new(0)
end
end
end
class Sine < Unary
def evaluate(environment = {})
Math.sin @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Sine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * Cosine.new(@parameter)).simplify
end
end
class Cosine < Unary
def evaluate(environment = {})
Math.cos @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Cosine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * (- Sine.new(@parameter))).simplify
end
-end
-
+end
-Zero = Number.new(0)
-One = Number.new(1)

Емил обнови решението на 14.11.2012 14:01 (преди почти 13 години)

class Expr
def self.build(expression)
case expression[0]
when :number then Number.new(expression[1])
when :variable then Variable.new(expression[1])
when :+ then Addition.new(build(expression[1]), build(expression[2]))
when :* then Multiplication.new(build(expression[1]), build(expression[2]))
when :- then Negation.new(build(expression[1]))
when :sin then Sine.new(build(expression[1]))
when :cos then Cosine.new(build(expression[1]))
end
end
def *(other)
if self == Number::ZERO || other == Number::ZERO
Number.new(0)
elsif self == Number::ONE
other
elsif other == Number::ONE
self
else
Multiplication.new(self, other)
end
end
def +(other)
if self == Number::ZERO
other
elsif other == Number::ZERO
self
else
Addition.new(self, other)
end
end
def -@
if self == Number::ZERO
@parameter
else
Negation.new(self)
end
end
end
class Unary < Expr
attr_accessor :parameter
def initialize(parameter)
@parameter = parameter
end
def ==(other)
if other.class == self.class
@parameter == other.parameter
end
end
def exact?
@parameter.exact?
end
end
class Binary < Expr
attr_accessor :parameter1, :parameter2
def initialize(parameter1, parameter2)
@parameter1, @parameter2 = parameter1, parameter2
end
def ==(other)
if other.class == self.class
@parameter1 == other.parameter1 && @parameter2 == other.parameter2
end
end
def exact?
@parameter1.exact? & @parameter2.exact?
end
end
class Number < Unary
ZERO = Number.new(0)
ONE = Number.new(1)
def evaluate(environment = {})
@parameter
end
def simplify
self
end
def exact?
true
end
def derive(variable)
Number.new(0)
end
+
+ def to_s
+ @parameter.to_s
+ end
end
class Addition < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) + @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify + @parameter2.simplify
end
end
def derive(variable)
(@parameter1.derive(variable) + @parameter2.derive(variable)).simplify
end
+
+ def to_s
+ "(#{@parameter1} + #{@parameter2})"
+ end
end
class Negation < Unary
def evaluate(environment = {})
-@parameter.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
-@parameter.simplify
end
end
def derive(variable)
(-@parameter.derive(variable)).simplify
end
+
+ def to_s
+ "-#{@parameter}"
+ end
end
class Multiplication < Binary
def evaluate(environment = {})
@parameter1.evaluate(environment) * @parameter2.evaluate(environment)
end
def simplify
if exact?
Number.new(evaluate)
else
@parameter1.simplify * @parameter2.simplify
end
end
def derive(variable)
result = @parameter1.derive(variable) * @parameter2 + @parameter1 * @parameter2.derive(variable)
result.simplify
end
+
+ def to_s
+ "(#{@parameter1} * #{@parameter2})"
+ end
end
class Variable < Unary
def evaluate(environment = {})
environment.values_at(@parameter)[0]
end
def simplify
self
end
def exact?
false
end
def derive(variable)
if variable == @parameter
Number.new(1)
else
Number.new(0)
end
end
+
+ def to_s
+ @parameter.to_s
+ end
end
class Sine < Unary
def evaluate(environment = {})
Math.sin @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Sine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * Cosine.new(@parameter)).simplify
end
+
+ def to_s
+ "sin(#{@parameter})"
+ end
end
class Cosine < Unary
def evaluate(environment = {})
Math.cos @parameter.evaluate(environment)
end
def simplify
if @parameter.exact?
Number.new(evaluate)
else
Cosine.new(@parameter.simplify)
end
end
def derive(variable)
(@parameter.derive(variable) * (- Sine.new(@parameter))).simplify
+ end
+
+ def to_s
+ "cos(#{@parameter})"
end
end