Support -- as an option

spec/options_spec.lua

@@ -136,6 +136,16 @@ describe("tests related to options", function()
          assert.same({input = {"bar", "-f", "--foo" , "bar"}}, args)
       end)
 
+      it("allows using -- as an option", function()
+         local parser = Parser()
+         parser:flag "--unrelated"
+         parser:option "--"
+            :args "*"
+            :target "tail"
+         local args = parser:parse{"--", "foo", "--unrelated", "bar"}
+         assert.same({tail = {"foo", "--unrelated", "bar"}}, args)
+      end)
+
       describe("Special chars set", function()
          it("handles windows-style options", function()
             local parser = Parser()

src/argparse.lua

@@ -1169,7 +1169,13 @@ function ParseState:parse(args)
 
                if arg:sub(2, 2) == first then
                   if #arg == 2 then
+                     if self.options[arg] then
+                        local option = self:get_option(arg)
+                        self:invoke(option, arg)
+                     else
                         self:close()
+                     end
+
                      self.handle_options = false
                   else
                      local equals = arg:find "="