Improved command line parsing

The first character after control character is now not required to be a letter

spec/help_spec.lua

@@ -23,12 +23,12 @@ describe("tests related to help message generation", function()
 
    it("uses custom help option", function()
       local parser = Parser "foo"
-         :add_help {aliases = {"\\?"}}
+         :add_help {name = "/?"}
       assert.equal(table.concat({
-         "Usage: foo [\\?]",
+         "Usage: foo [/?]",
          "",
          "Options: ",
-         "   \\?                    Show this help message and exit. "
+         "   /?                    Show this help message and exit. "
       }, "\r\n"), parser:prepare():get_help())
    end)
 

spec/options_spec.lua

@@ -16,6 +16,14 @@ describe("tests related to options", function()
          assert.same({server = "foo"}, args)
       end)
 
+      it("handles non-standard charset", function()
+         local parser = Parser()
+         parser:option "/s"
+         parser:flag "/?"
+         local args = parser:parse{"/s", "foo", "/?"}
+         assert.same({s = "foo", ["?"] = true}, args)
+      end)
+
       it("handles GNU-style long options", function()
          local parser = Parser()
          parser:option("-s", "--server")