Clean up the API a little

README.md

@@ -30,35 +30,44 @@ Usage
     require 'rubygems'
     require 'options_library'
 
-    call = Option::Call.new
-    call.underlying = 95.40  # spot price of the underlying
-    call.strike = 90.00  # strike price of option
-    call.time = 0.015 # time in years
-    call.interest = 0.01 # equates to 1% risk free interest
-    call.sigma = 0.4875  # equates to 48.75% volatility
-    call.dividend = 0.0  # no annual dividend yield
-
-    price = call.calc_price # theoretical value of the option
-    delta = call.calc_delta # option price sensitivity to a change in underlying price
-    gamma = call.calc_gamma # option delta sensitivity to a change in underlying price
-    vega  = call.calc_vega  # option price sensitivity to a change in sigma (volatility)
-
-    implied_vol = call.calc_implied_vol( 1.80 ) # implied volatility based on the target price 
+    # Build the option out with a block builder
+    call = Option::Call.new do
+      underlying 95.40  # spot price of the underlying
+      strike     90.5   # strike price of option
+      time       0.015  # time in years
+      interest   0.01   # equates to 1% risk free interest
+      sigma      0.4875 # equates to 48.75% volatility
+      dividend   0.05   # 5% annual dividend yield
+    end
+
+    # Values are calculated when requested
+    p call.price # theoretical value of the option
+    p call.delta # option price sensitivity to a change in underlying price
+    p call.gamma # option delta sensitivity to a change in underlying price
+    p call.vega  # option price sensitivity to a change in sigma (volatility)
+
+    # implied volatility based on a target price
+    p call.implied_vol_for_price( 1.80 )
 
     # Or go straight at the Calculator methods
     # Option::Calculator.price_call( underlying, strike, time, interest, sigma, dividend )
-    call_price = Option::Calculator.price_call( 94.5, 90.5, 0.015, 0.01, 0.4875, 0.0 ) 
-
-Testing
--------
-
-To run the tests:
-
-    $ rake
-
-To add tests see the `Commands` section earlier in this
-README.
+    call_price = Option::Calculator.price_call( 95.40, 90.5, 0.015, 0.01, 0.4875, 0.05 )
 
+    # Deprecated API
+    call = Option::Call.new
+    call.underlying = 95.40
+    call.strike = 90.00
+    call.time = 0.015
+    call.interest = 0.01
+    call.sigma = 0.4875
+    call.dividend = 0.0
+
+    price = call.calc_price
+    delta = call.calc_delta
+    gamma = call.calc_gamma
+    vega  = call.calc_vega
+
+    implied_vol = call.calc_implied_vol( 1.80 )
 
 Contributing
 ------------

lib/options_library/option_call.rb

@@ -5,8 +5,8 @@
 module Option
   class Call < Model
 
-    def initialize
-      super(:call)
+    def initialize(&blk)
+      super(:call, &blk)
     end
 
   end

lib/options_library/option_model.rb

@@ -14,42 +14,90 @@ class Model
     CALC_THETA_METHODS  = { :call=>Calculator.method('theta_call'),       :put=>Calculator.method('theta_put') }
     IMPLIED_VOL_METHODS = { :call=>Calculator.method('implied_vol_call'), :put=>Calculator.method('implied_vol_put') }
 
-    attr_accessor :underlying, :strike, :time, :interest, :sigma, :dividend, :option_type
+    attr_accessor :option_type
+
+    def initialize(option_type, &blk)
+      raise 'Unknown option_type' unless KNOWN_OPTION_TYPES.include?(option_type)
 
-    def initialize(option_type)
       self.option_type = option_type
       self.underlying = 0.0
       self.strike = 0.0
       self.time = 0.0
       self.interest = 0.0
       self.sigma = 0.0
       self.dividend = 0.0
-      raise 'Unknown option_type' unless KNOWN_OPTION_TYPES.include?(option_type) 
+
+      if block_given?
+        # http://graysoftinc.com/ruby-voodoo/dsl-block-styles
+        blk.arity == 1 ? blk.call(self) : instance_eval(&blk)
+      end
+    end
+
+    def underlying(value=nil)
+      @underlying = value if value
+      @underlying
+    end
+    alias_method :underlying=, :underlying
+
+    def strike(value=nil)
+      @strike = value if value
+      @strike
+    end
+    alias_method :strike=, :strike
+
+    def time(value=nil)
+      @time = value if value
+      @time
+    end
+    alias_method :time=, :time
+
+    def interest(value=nil)
+      @interest = value if value
+      @interest
+    end
+    alias_method :interest=, :interest
+
+    def sigma(value=nil)
+      @sigma = value if value
+      @sigma
+    end
+    alias_method :sigma=, :sigma
+
+    def dividend(value=nil)
+      @dividend = value if value
+      @dividend
     end
+    alias_method :dividend=, :dividend
 
     def calc_price
       CALC_PRICE_METHODS[option_type].call(underlying, strike, time, interest, sigma, dividend)
     end
+    alias_method :price, :calc_price
 
     def calc_delta
       CALC_DELTA_METHODS[option_type].call(underlying, strike, time, interest, sigma, dividend)
     end
+    alias_method :delta, :calc_delta
 
     def calc_gamma
       Calculator.gamma(underlying, strike, time, interest, sigma, dividend)
     end
+    alias_method :gamma, :calc_gamma
 
     def calc_theta
       CALC_THETA_METHODS[option_type].call(underlying, strike, time, interest, sigma, dividend)
     end
+    alias_method :theta, :calc_theta
 
     def calc_vega
       Calculator.vega(underlying, strike, time, interest, sigma, dividend)
     end
+    alias_method :vega, :calc_vega
 
     def calc_implied_vol(target_price)
       IMPLIED_VOL_METHODS[option_type].call(underlying, strike, time, interest, target_price, dividend)
     end
+    alias_method :implied_vol_for_price, :calc_implied_vol
 
   end
 end

lib/options_library/option_put.rb

@@ -5,8 +5,8 @@
 module Option
   class Put < Model
 
-    def initialize
-      super(:put)
+    def initialize(&blk)
+      super(:put, &blk)
     end
 
   end

options_library.gemspec

@@ -2,21 +2,37 @@
 
 Gem::Specification.new do |s|
   s.name = %q{options_library}
-  s.version = "1.0.3"
+  s.version = "1.0.4"
 
   s.required_rubygems_version = Gem::Requirement.new(">= 1.2") if s.respond_to? :required_rubygems_version=
   s.authors = ["Dan Tylenda-Emmons"]
-  s.date = %q{2011-02-17}
-  s.description = %q{A gem used to calc the price of an option.}
+  s.date = %q{2016-06-22}
+  s.description = %q{A gem used to calc the price of call and put options.}
   s.email = %q{jrubyist@gmail.com}
-  s.extra_rdoc_files = ["README.md", "lib/options_library.rb", "lib/options_library/option_calculator.rb", "lib/options_library/option_call.rb", "lib/options_library/option_model.rb", "lib/options_library/option_put.rb"]
-  s.files = ["Manifest", "README.md", "Rakefile", "lib/options_library.rb", "lib/options_library/option_calculator.rb", "lib/options_library/option_call.rb", "lib/options_library/option_model.rb", "lib/options_library/option_put.rb", "options_library.gemspec", "options_library/options_library.iml"]
+  s.extra_rdoc_files = [
+    "README.md",
+    "lib/options_library.rb",
+    "lib/options_library/option_calculator.rb",
+    "lib/options_library/option_call.rb",
+    "lib/options_library/option_model.rb",
+    "lib/options_library/option_put.rb"]
+  s.files = [
+    "Manifest",
+    "README.md",
+    "lib/options_library.rb",
+    "lib/options_library/option_calculator.rb",
+    "lib/options_library/option_call.rb",
+    "lib/options_library/option_model.rb",
+    "lib/options_library/option_put.rb",
+    "options_library.gemspec"]
   s.homepage = %q{http://github.com/codertrader/options_library}
   s.rdoc_options = ["--line-numbers", "--inline-source", "--title", "Options_library", "--main", "README.md"]
   s.require_paths = ["lib"]
   s.rubyforge_project = %q{options_library}
   s.rubygems_version = %q{1.5.2}
-  s.summary = %q{A gem used to calc the price of an option.}
+  s.summary = %q{A gem used to calc the price of call and put options. Can also produce all of the greeks and will compute
+  implied volatility given a target price.}
+  s.license = "0BSD"
 
   if s.respond_to? :specification_version then
     s.specification_version = 3