implement :boolean option flag

lib/yawpa.rb

@@ -73,12 +73,22 @@ module Yawpa
       param = params[i]
       if param =~ /^--([^=]+)(?:=(.+))?$/
         param_name, val = $1, $2
+        bool_val = true
         if options[param_name].nil?
-          raise ArgumentParsingException.new("Unknown option '#{param_name}'")
+          if param_name =~ /^no(.*)$/
+            test_param_name = $1
+            if options[test_param_name]
+              param_name = test_param_name
+              bool_val = false
+            end
+          end
         end
         opt_config = options[param_name]
+        raise ArgumentParsingException.new("Unknown option '#{param_name}'") unless opt_config
         param_key = opt_config[:key]
-        if opt_config[:nargs].last == 0
+        if opt_config[:boolean]
+          opts[param_key] = bool_val
+        elsif opt_config[:nargs].last == 0
           opts[param_key] = true
         else
           opts[param_key] = []
@@ -155,6 +165,7 @@ module Yawpa
         nargs = (nargs..nargs) if nargs.is_a?(Fixnum)
         newopts[newkey][:nargs] = nargs
         newopts[newkey][:short] = v[:short] || ''
+        newopts[newkey][:boolean] = v[:boolean]
       end
     end
   end

spec/yawpa_spec.rb

@@ -1,7 +1,7 @@
 require 'spec_helper'
 
 describe Yawpa do
-  describe 'parse' do
+  describe ".parse" do
     it "returns everything as arguments when no options present" do
       options = { }
       params = ['one', 'two', 'three', 'four']
@@ -213,5 +213,23 @@ describe Yawpa do
       expect(opts[:two]).to be_falsey
       expect(args).to eq(['arg', '--two'])
     end
+
+    it "supports :boolean option flag" do
+      options = {
+        push: {boolean: true},
+      }
+
+      opts, args = Yawpa.parse(%w[hi], options)
+      expect(opts).to eq({})
+      expect(args).to eq(%w[hi])
+
+      opts, args = Yawpa.parse(%w[--push one two], options)
+      expect(opts).to eq(push: true)
+      expect(args).to eq(%w[one two])
+
+      opts, args = Yawpa.parse(%w[arg --nopush], options)
+      expect(opts).to eq(push: false)
+      expect(args).to eq(%w[arg])
+    end
   end
 end