diff --git a/README.md b/README.md
index 4b9fb61..9ba3852 100644
--- a/README.md
+++ b/README.md
@@ -11,8 +11,6 @@ Almost everything is implemented, and a WIP version will be available soon.
 TODO till first release: 
 
 * Add `Content` section to this README. 
-* Add information about the parsing algorithm to the tutorial. 
-* Add information about the way arguments are stored in the result table to the tutorial. 
 * Add a small example to the beginning of this README. 
 * Check the grammar in this README. 
 * Generate .html file from the tutorial part of this README and put it into `doc` directory. 
@@ -785,7 +783,20 @@ Error: option '-o' must be used at most 1 time
 
 #### Generating usage and help messages
 
-`get_help` and `get_usage` methods of Parser and Command classes can be used to generate their help and usage messages. 
+`:get_help()` and `get_usage:()` methods of Parser and Command classes can be used to generate their help and usage messages. 
+
+#### Parsing algorithm
+
+argparse interprets command-line arguments in the following way: 
+
+Argument | Interpretation
+--- | ---
+`foo` | An argument of an option or a positional argument. 
+`--foo` | An option. 
+`--foo=bar` | An option and its argument. The option must be able to take arguments. 
+`-f` | An option. 
+`-abcdef` | Letters are interpreted as options. If one of them can take an argument, the rest of the string is passed to it. 
+`--` | The rest of the command-line arguments will be interpreted as positional arguments. 
 
 ## Documentation
 
diff --git a/spec/options_spec.lua b/spec/options_spec.lua
index 2a624af..ab2d300 100644
--- a/spec/options_spec.lua
+++ b/spec/options_spec.lua
@@ -88,6 +88,35 @@ describe("tests related to options", function()
          assert.same({quiet = true, server = "foo"}, args)
       end)
 
+      it("interprets extra option arguments as positional arguments", function()
+         local parser = Parser()
+         parser:argument "input"
+            :args "2+"
+         parser:option "-s" "--server"
+         local args = parser:parse{"foo", "-sFROM", "bar"}
+         assert.same({input = {"foo", "bar"}, server = "FROM"}, args)
+      end)
+
+      it("does not interpret extra option arguments as other option's arguments", function()
+         local parser = Parser()
+         parser:argument "output"
+         parser:option "--input"
+            :args "+"
+         parser:option "-s" "--server"
+         local args = parser:parse{"--input", "foo", "-sFROM", "bar"}
+         assert.same({input = {"foo"}, server = "FROM", output = "bar"}, args)
+      end)
+
+      it("does not pass arguments to options after double hyphen", function()
+         local parser = Parser()
+         parser:argument "input"
+            :args "?"
+         parser:option "--exclude"
+            :args "*"
+         local args = parser:parse{"--exclude", "--", "foo"}
+         assert.same({input = "foo", exclude = {}}, args)
+      end)
+
       describe("Special chars set", function()
          it("handles windows-style options", function()
             local parser = Parser()
@@ -106,8 +135,8 @@ describe("tests related to options", function()
                :count "*"
             parser:command "deep"
                :add_help(false)
-               :option "\\s"
-            local args = parser:parse{"-v", "deep", "\\s", "foo", "-vv"}
+               :option "/s"
+            local args = parser:parse{"-v", "deep", "/s", "foo", "-vv"}
             assert.same({verbose = 3, deep = true, s = "foo"}, args)
          end)
       end)
diff --git a/src/argparse.lua b/src/argparse.lua
index 540caaa..d9125ef 100644
--- a/src/argparse.lua
+++ b/src/argparse.lua
@@ -790,6 +790,10 @@ function Parser:_parse(args, errhandler)
                   plain = false
                   if data:sub(2, 2) == first then
                      if #data == 2 then
+                        if cur_option then
+                           close(cur_option)
+                        end
+
                         handle_options = false
                      else
                         local equal = data:find "="