Move parse_cmdline() to libbuild2

1 files changed, 1710 insertions, 0 deletions

diff --git a/libbuild2/b-options.cxx b/libbuild2/b-options.cxx
new file mode 100644
index 0000000..86f5bfe
--- /dev/null
+++ b/libbuild2/b-options.cxx
@@ -0,0 +1,1710 @@
+// -*- C++ -*-
+//
+// This file was generated by CLI, a command line interface
+// compiler for C++.
+//
+
+// Begin prologue.
+//
+#include <libbuild2/types-parsers.hxx>
+//
+// End prologue.
+
+#include <libbuild2/b-options.hxx>
+
+#include <map>
+#include <set>
+#include <string>
+#include <vector>
+#include <utility>
+#include <ostream>
+#include <sstream>
+#include <cstring>
+#include <fstream>
+
+namespace build2
+{
+  namespace build
+  {
+    namespace cli
+    {
+      // unknown_option
+      //
+      unknown_option::
+      ~unknown_option () throw ()
+      {
+      }
+
+      void unknown_option::
+      print (::std::ostream& os) const
+      {
+        os << "unknown option '" << option ().c_str () << "'";
+      }
+
+      const char* unknown_option::
+      what () const throw ()
+      {
+        return "unknown option";
+      }
+
+      // unknown_argument
+      //
+      unknown_argument::
+      ~unknown_argument () throw ()
+      {
+      }
+
+      void unknown_argument::
+      print (::std::ostream& os) const
+      {
+        os << "unknown argument '" << argument ().c_str () << "'";
+      }
+
+      const char* unknown_argument::
+      what () const throw ()
+      {
+        return "unknown argument";
+      }
+
+      // missing_value
+      //
+      missing_value::
+      ~missing_value () throw ()
+      {
+      }
+
+      void missing_value::
+      print (::std::ostream& os) const
+      {
+        os << "missing value for option '" << option ().c_str () << "'";
+      }
+
+      const char* missing_value::
+      what () const throw ()
+      {
+        return "missing option value";
+      }
+
+      // invalid_value
+      //
+      invalid_value::
+      ~invalid_value () throw ()
+      {
+      }
+
+      void invalid_value::
+      print (::std::ostream& os) const
+      {
+        os << "invalid value '" << value ().c_str () << "' for option '"
+           << option ().c_str () << "'";
+
+        if (!message ().empty ())
+          os << ": " << message ().c_str ();
+      }
+
+      const char* invalid_value::
+      what () const throw ()
+      {
+        return "invalid option value";
+      }
+
+      // eos_reached
+      //
+      void eos_reached::
+      print (::std::ostream& os) const
+      {
+        os << what ();
+      }
+
+      const char* eos_reached::
+      what () const throw ()
+      {
+        return "end of argument stream reached";
+      }
+
+      // file_io_failure
+      //
+      file_io_failure::
+      ~file_io_failure () throw ()
+      {
+      }
+
+      void file_io_failure::
+      print (::std::ostream& os) const
+      {
+        os << "unable to open file '" << file ().c_str () << "' or read failure";
+      }
+
+      const char* file_io_failure::
+      what () const throw ()
+      {
+        return "unable to open file or read failure";
+      }
+
+      // unmatched_quote
+      //
+      unmatched_quote::
+      ~unmatched_quote () throw ()
+      {
+      }
+
+      void unmatched_quote::
+      print (::std::ostream& os) const
+      {
+        os << "unmatched quote in argument '" << argument ().c_str () << "'";
+      }
+
+      const char* unmatched_quote::
+      what () const throw ()
+      {
+        return "unmatched quote";
+      }
+
+      // scanner
+      //
+      scanner::
+      ~scanner ()
+      {
+      }
+
+      // argv_scanner
+      //
+      bool argv_scanner::
+      more ()
+      {
+        return i_ < argc_;
+      }
+
+      const char* argv_scanner::
+      peek ()
+      {
+        if (i_ < argc_)
+          return argv_[i_];
+        else
+          throw eos_reached ();
+      }
+
+      const char* argv_scanner::
+      next ()
+      {
+        if (i_ < argc_)
+        {
+          const char* r (argv_[i_]);
+
+          if (erase_)
+          {
+            for (int i (i_ + 1); i < argc_; ++i)
+              argv_[i - 1] = argv_[i];
+
+            --argc_;
+            argv_[argc_] = 0;
+          }
+          else
+            ++i_;
+
+          ++start_position_;
+          return r;
+        }
+        else
+          throw eos_reached ();
+      }
+
+      void argv_scanner::
+      skip ()
+      {
+        if (i_ < argc_)
+        {
+          ++i_;
+          ++start_position_;
+        }
+        else
+          throw eos_reached ();
+      }
+
+      std::size_t argv_scanner::
+      position ()
+      {
+        return start_position_;
+      }
+
+      // argv_file_scanner
+      //
+      int argv_file_scanner::zero_argc_ = 0;
+      std::string argv_file_scanner::empty_string_;
+
+      bool argv_file_scanner::
+      more ()
+      {
+        if (!args_.empty ())
+          return true;
+
+        while (base::more ())
+        {
+          // See if the next argument is the file option.
+          //
+          const char* a (base::peek ());
+          const option_info* oi = 0;
+          const char* ov = 0;
+
+          if (!skip_)
+          {
+            if ((oi = find (a)) != 0)
+            {
+              base::next ();
+
+              if (!base::more ())
+                throw missing_value (a);
+
+              ov = base::next ();
+            }
+            else if (std::strncmp (a, "-", 1) == 0)
+            {
+              if ((ov = std::strchr (a, '=')) != 0)
+              {
+                std::string o (a, 0, ov - a);
+                if ((oi = find (o.c_str ())) != 0)
+                {
+                  base::next ();
+                  ++ov;
+                }
+              }
+            }
+          }
+
+          if (oi != 0)
+          {
+            if (oi->search_func != 0)
+            {
+              std::string f (oi->search_func (ov, oi->arg));
+
+              if (!f.empty ())
+                load (f);
+            }
+            else
+              load (ov);
+
+            if (!args_.empty ())
+              return true;
+          }
+          else
+          {
+            if (!skip_)
+              skip_ = (std::strcmp (a, "--") == 0);
+
+            return true;
+          }
+        }
+
+        return false;
+      }
+
+      const char* argv_file_scanner::
+      peek ()
+      {
+        if (!more ())
+          throw eos_reached ();
+
+        return args_.empty () ? base::peek () : args_.front ().value.c_str ();
+      }
+
+      const std::string& argv_file_scanner::
+      peek_file ()
+      {
+        if (!more ())
+          throw eos_reached ();
+
+        return args_.empty () ? empty_string_ : *args_.front ().file;
+      }
+
+      std::size_t argv_file_scanner::
+      peek_line ()
+      {
+        if (!more ())
+          throw eos_reached ();
+
+        return args_.empty () ? 0 : args_.front ().line;
+      }
+
+      const char* argv_file_scanner::
+      next ()
+      {
+        if (!more ())
+          throw eos_reached ();
+
+        if (args_.empty ())
+          return base::next ();
+        else
+        {
+          hold_[i_ == 0 ? ++i_ : --i_].swap (args_.front ().value);
+          args_.pop_front ();
+          ++start_position_;
+          return hold_[i_].c_str ();
+        }
+      }
+
+      void argv_file_scanner::
+      skip ()
+      {
+        if (!more ())
+          throw eos_reached ();
+
+        if (args_.empty ())
+          return base::skip ();
+        else
+        {
+          args_.pop_front ();
+          ++start_position_;
+        }
+      }
+
+      const argv_file_scanner::option_info* argv_file_scanner::
+      find (const char* a) const
+      {
+        for (std::size_t i (0); i < options_count_; ++i)
+          if (std::strcmp (a, options_[i].option) == 0)
+            return &options_[i];
+
+        return 0;
+      }
+
+      std::size_t argv_file_scanner::
+      position ()
+      {
+        return start_position_;
+      }
+
+      void argv_file_scanner::
+      load (const std::string& file)
+      {
+        using namespace std;
+
+        ifstream is (file.c_str ());
+
+        if (!is.is_open ())
+          throw file_io_failure (file);
+
+        files_.push_back (file);
+
+        arg a;
+        a.file = &*files_.rbegin ();
+
+        for (a.line = 1; !is.eof (); ++a.line)
+        {
+          string line;
+          getline (is, line);
+
+          if (is.fail () && !is.eof ())
+            throw file_io_failure (file);
+
+          string::size_type n (line.size ());
+
+          // Trim the line from leading and trailing whitespaces.
+          //
+          if (n != 0)
+          {
+            const char* f (line.c_str ());
+            const char* l (f + n);
+
+            const char* of (f);
+            while (f < l && (*f == ' ' || *f == '\t' || *f == '\r'))
+              ++f;
+
+            --l;
+
+            const char* ol (l);
+            while (l > f && (*l == ' ' || *l == '\t' || *l == '\r'))
+              --l;
+
+            if (f != of || l != ol)
+              line = f <= l ? string (f, l - f + 1) : string ();
+          }
+
+          // Ignore empty lines, those that start with #.
+          //
+          if (line.empty () || line[0] == '#')
+            continue;
+
+          string::size_type p (string::npos);
+          if (line.compare (0, 1, "-") == 0)
+          {
+            p = line.find (' ');
+
+            string::size_type q (line.find ('='));
+            if (q != string::npos && q < p)
+              p = q;
+          }
+
+          string s1;
+          if (p != string::npos)
+          {
+            s1.assign (line, 0, p);
+
+            // Skip leading whitespaces in the argument.
+            //
+            if (line[p] == '=')
+              ++p;
+            else
+            {
+              n = line.size ();
+              for (++p; p < n; ++p)
+              {
+                char c (line[p]);
+                if (c != ' ' && c != '\t' && c != '\r')
+                  break;
+              }
+            }
+          }
+          else if (!skip_)
+            skip_ = (line == "--");
+
+          string s2 (line, p != string::npos ? p : 0);
+
+          // If the string (which is an option value or argument) is
+          // wrapped in quotes, remove them.
+          //
+          n = s2.size ();
+          char cf (s2[0]), cl (s2[n - 1]);
+
+          if (cf == '"' || cf == '\'' || cl == '"' || cl == '\'')
+          {
+            if (n == 1 || cf != cl)
+              throw unmatched_quote (s2);
+
+            s2 = string (s2, 1, n - 2);
+          }
+
+          if (!s1.empty ())
+          {
+            // See if this is another file option.
+            //
+            const option_info* oi;
+            if (!skip_ && (oi = find (s1.c_str ())))
+            {
+              if (s2.empty ())
+                throw missing_value (oi->option);
+
+              if (oi->search_func != 0)
+              {
+                string f (oi->search_func (s2.c_str (), oi->arg));
+                if (!f.empty ())
+                  load (f);
+              }
+              else
+              {
+                // If the path of the file being parsed is not simple and the
+                // path of the file that needs to be loaded is relative, then
+                // complete the latter using the former as a base.
+                //
+#ifndef _WIN32
+                string::size_type p (file.find_last_of ('/'));
+                bool c (p != string::npos && s2[0] != '/');
+#else
+                string::size_type p (file.find_last_of ("/\\"));
+                bool c (p != string::npos && s2[1] != ':');
+#endif
+                if (c)
+                  s2.insert (0, file, 0, p + 1);
+
+                load (s2);
+              }
+
+              continue;
+            }
+
+            a.value = s1;
+            args_.push_back (a);
+          }
+
+          a.value = s2;
+          args_.push_back (a);
+        }
+      }
+
+      template <typename X>
+      struct parser
+      {
+        static void
+        parse (X& x, bool& xs, scanner& s)
+        {
+          using namespace std;
+
+          const char* o (s.next ());
+          if (s.more ())
+          {
+            string v (s.next ());
+            istringstream is (v);
+            if (!(is >> x && is.peek () == istringstream::traits_type::eof ()))
+              throw invalid_value (o, v);
+          }
+          else
+            throw missing_value (o);
+
+          xs = true;
+        }
+
+        static void
+        merge (X& b, const X& a)
+        {
+          b = a;
+        }
+      };
+
+      template <>
+      struct parser<bool>
+      {
+        static void
+        parse (bool& x, scanner& s)
+        {
+          s.next ();
+          x = true;
+        }
+
+        static void
+        merge (bool& b, const bool&)
+        {
+          b = true;
+        }
+      };
+
+      template <>
+      struct parser<std::string>
+      {
+        static void
+        parse (std::string& x, bool& xs, scanner& s)
+        {
+          const char* o (s.next ());
+
+          if (s.more ())
+            x = s.next ();
+          else
+            throw missing_value (o);
+
+          xs = true;
+        }
+
+        static void
+        merge (std::string& b, const std::string& a)
+        {
+          b = a;
+        }
+      };
+
+      template <typename X>
+      struct parser<std::pair<X, std::size_t> >
+      {
+        static void
+        parse (std::pair<X, std::size_t>& x, bool& xs, scanner& s)
+        {
+          x.second = s.position ();
+          parser<X>::parse (x.first, xs, s);
+        }
+
+        static void
+        merge (std::pair<X, std::size_t>& b, const std::pair<X, std::size_t>& a)
+        {
+          b = a;
+        }
+      };
+
+      template <typename X>
+      struct parser<std::vector<X> >
+      {
+        static void
+        parse (std::vector<X>& c, bool& xs, scanner& s)
+        {
+          X x;
+          bool dummy;
+          parser<X>::parse (x, dummy, s);
+          c.push_back (x);
+          xs = true;
+        }
+
+        static void
+        merge (std::vector<X>& b, const std::vector<X>& a)
+        {
+          b.insert (b.end (), a.begin (), a.end ());
+        }
+      };
+
+      template <typename X, typename C>
+      struct parser<std::set<X, C> >
+      {
+        static void
+        parse (std::set<X, C>& c, bool& xs, scanner& s)
+        {
+          X x;
+          bool dummy;
+          parser<X>::parse (x, dummy, s);
+          c.insert (x);
+          xs = true;
+        }
+
+        static void
+        merge (std::set<X, C>& b, const std::set<X, C>& a)
+        {
+          b.insert (a.begin (), a.end ());
+        }
+      };
+
+      template <typename K, typename V, typename C>
+      struct parser<std::map<K, V, C> >
+      {
+        static void
+        parse (std::map<K, V, C>& m, bool& xs, scanner& s)
+        {
+          const char* o (s.next ());
+
+          if (s.more ())
+          {
+            std::size_t pos (s.position ());
+            std::string ov (s.next ());
+            std::string::size_type p = ov.find ('=');
+
+            K k = K ();
+            V v = V ();
+            std::string kstr (ov, 0, p);
+            std::string vstr (ov, (p != std::string::npos ? p + 1 : ov.size ()));
+
+            int ac (2);
+            char* av[] =
+            {
+              const_cast<char*> (o),
+              0
+            };
+
+            bool dummy;
+            if (!kstr.empty ())
+            {
+              av[1] = const_cast<char*> (kstr.c_str ());
+              argv_scanner s (0, ac, av, false, pos);
+              parser<K>::parse (k, dummy, s);
+            }
+
+            if (!vstr.empty ())
+            {
+              av[1] = const_cast<char*> (vstr.c_str ());
+              argv_scanner s (0, ac, av, false, pos);
+              parser<V>::parse (v, dummy, s);
+            }
+
+            m[k] = v;
+          }
+          else
+            throw missing_value (o);
+
+          xs = true;
+        }
+
+        static void
+        merge (std::map<K, V, C>& b, const std::map<K, V, C>& a)
+        {
+          for (typename std::map<K, V, C>::const_iterator i (a.begin ()); 
+               i != a.end (); 
+               ++i)
+            b[i->first] = i->second;
+        }
+      };
+
+      template <typename X, typename T, T X::*M>
+      void
+      thunk (X& x, scanner& s)
+      {
+        parser<T>::parse (x.*M, s);
+      }
+
+      template <typename X, typename T, T X::*M, bool X::*S>
+      void
+      thunk (X& x, scanner& s)
+      {
+        parser<T>::parse (x.*M, x.*S, s);
+      }
+    }
+  }
+}
+
+#include <map>
+#include <cstring>
+
+namespace build2
+{
+  // options
+  //
+
+  options::
+  options ()
+  : build2_metadata_ (),
+    build2_metadata_specified_ (false),
+    v_ (),
+    V_ (),
+    quiet_ (),
+    silent_ (),
+    verbose_ (1),
+    verbose_specified_ (false),
+    stat_ (),
+    dump_ (),
+    dump_specified_ (false),
+    progress_ (),
+    no_progress_ (),
+    jobs_ (),
+    jobs_specified_ (false),
+    max_jobs_ (),
+    max_jobs_specified_ (false),
+    queue_depth_ (4),
+    queue_depth_specified_ (false),
+    file_cache_ (),
+    file_cache_specified_ (false),
+    max_stack_ (),
+    max_stack_specified_ (false),
+    serial_stop_ (),
+    dry_run_ (),
+    match_only_ (),
+    no_external_modules_ (),
+    structured_result_ (),
+    mtime_check_ (),
+    no_mtime_check_ (),
+    no_column_ (),
+    no_line_ (),
+    buildfile_ (),
+    buildfile_specified_ (false),
+    config_guess_ (),
+    config_guess_specified_ (false),
+    config_sub_ (),
+    config_sub_specified_ (false),
+    pager_ (),
+    pager_specified_ (false),
+    pager_option_ (),
+    pager_option_specified_ (false),
+    options_file_ (),
+    options_file_specified_ (false),
+    default_options_ (),
+    default_options_specified_ (false),
+    no_default_options_ (),
+    help_ (),
+    version_ ()
+  {
+  }
+
+  bool options::
+  parse (int& argc,
+         char** argv,
+         bool erase,
+         ::build2::build::cli::unknown_mode opt,
+         ::build2::build::cli::unknown_mode arg)
+  {
+    ::build2::build::cli::argv_scanner s (argc, argv, erase);
+    bool r = _parse (s, opt, arg);
+    return r;
+  }
+
+  bool options::
+  parse (int start,
+         int& argc,
+         char** argv,
+         bool erase,
+         ::build2::build::cli::unknown_mode opt,
+         ::build2::build::cli::unknown_mode arg)
+  {
+    ::build2::build::cli::argv_scanner s (start, argc, argv, erase);
+    bool r = _parse (s, opt, arg);
+    return r;
+  }
+
+  bool options::
+  parse (int& argc,
+         char** argv,
+         int& end,
+         bool erase,
+         ::build2::build::cli::unknown_mode opt,
+         ::build2::build::cli::unknown_mode arg)
+  {
+    ::build2::build::cli::argv_scanner s (argc, argv, erase);
+    bool r = _parse (s, opt, arg);
+    end = s.end ();
+    return r;
+  }
+
+  bool options::
+  parse (int start,
+         int& argc,
+         char** argv,
+         int& end,
+         bool erase,
+         ::build2::build::cli::unknown_mode opt,
+         ::build2::build::cli::unknown_mode arg)
+  {
+    ::build2::build::cli::argv_scanner s (start, argc, argv, erase);
+    bool r = _parse (s, opt, arg);
+    end = s.end ();
+    return r;
+  }
+
+  bool options::
+  parse (::build2::build::cli::scanner& s,
+         ::build2::build::cli::unknown_mode opt,
+         ::build2::build::cli::unknown_mode arg)
+  {
+    bool r = _parse (s, opt, arg);
+    return r;
+  }
+
+  void options::
+  merge (const options& a)
+  {
+    CLI_POTENTIALLY_UNUSED (a);
+
+    if (a.build2_metadata_specified_)
+    {
+      ::build2::build::cli::parser< uint64_t>::merge (
+        this->build2_metadata_, a.build2_metadata_);
+      this->build2_metadata_specified_ = true;
+    }
+
+    if (a.v_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->v_, a.v_);
+    }
+
+    if (a.V_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->V_, a.V_);
+    }
+
+    if (a.quiet_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->quiet_, a.quiet_);
+    }
+
+    if (a.silent_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->silent_, a.silent_);
+    }
+
+    if (a.verbose_specified_)
+    {
+      ::build2::build::cli::parser< uint16_t>::merge (
+        this->verbose_, a.verbose_);
+      this->verbose_specified_ = true;
+    }
+
+    if (a.stat_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->stat_, a.stat_);
+    }
+
+    if (a.dump_specified_)
+    {
+      ::build2::build::cli::parser< std::set<string>>::merge (
+        this->dump_, a.dump_);
+      this->dump_specified_ = true;
+    }
+
+    if (a.progress_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->progress_, a.progress_);
+    }
+
+    if (a.no_progress_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->no_progress_, a.no_progress_);
+    }
+
+    if (a.jobs_specified_)
+    {
+      ::build2::build::cli::parser< size_t>::merge (
+        this->jobs_, a.jobs_);
+      this->jobs_specified_ = true;
+    }
+
+    if (a.max_jobs_specified_)
+    {
+      ::build2::build::cli::parser< size_t>::merge (
+        this->max_jobs_, a.max_jobs_);
+      this->max_jobs_specified_ = true;
+    }
+
+    if (a.queue_depth_specified_)
+    {
+      ::build2::build::cli::parser< size_t>::merge (
+        this->queue_depth_, a.queue_depth_);
+      this->queue_depth_specified_ = true;
+    }
+
+    if (a.file_cache_specified_)
+    {
+      ::build2::build::cli::parser< string>::merge (
+        this->file_cache_, a.file_cache_);
+      this->file_cache_specified_ = true;
+    }
+
+    if (a.max_stack_specified_)
+    {
+      ::build2::build::cli::parser< size_t>::merge (
+        this->max_stack_, a.max_stack_);
+      this->max_stack_specified_ = true;
+    }
+
+    if (a.serial_stop_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->serial_stop_, a.serial_stop_);
+    }
+
+    if (a.dry_run_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->dry_run_, a.dry_run_);
+    }
+
+    if (a.match_only_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->match_only_, a.match_only_);
+    }
+
+    if (a.no_external_modules_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->no_external_modules_, a.no_external_modules_);
+    }
+
+    if (a.structured_result_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->structured_result_, a.structured_result_);
+    }
+
+    if (a.mtime_check_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->mtime_check_, a.mtime_check_);
+    }
+
+    if (a.no_mtime_check_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->no_mtime_check_, a.no_mtime_check_);
+    }
+
+    if (a.no_column_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->no_column_, a.no_column_);
+    }
+
+    if (a.no_line_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->no_line_, a.no_line_);
+    }
+
+    if (a.buildfile_specified_)
+    {
+      ::build2::build::cli::parser< path>::merge (
+        this->buildfile_, a.buildfile_);
+      this->buildfile_specified_ = true;
+    }
+
+    if (a.config_guess_specified_)
+    {
+      ::build2::build::cli::parser< path>::merge (
+        this->config_guess_, a.config_guess_);
+      this->config_guess_specified_ = true;
+    }
+
+    if (a.config_sub_specified_)
+    {
+      ::build2::build::cli::parser< path>::merge (
+        this->config_sub_, a.config_sub_);
+      this->config_sub_specified_ = true;
+    }
+
+    if (a.pager_specified_)
+    {
+      ::build2::build::cli::parser< string>::merge (
+        this->pager_, a.pager_);
+      this->pager_specified_ = true;
+    }
+
+    if (a.pager_option_specified_)
+    {
+      ::build2::build::cli::parser< strings>::merge (
+        this->pager_option_, a.pager_option_);
+      this->pager_option_specified_ = true;
+    }
+
+    if (a.options_file_specified_)
+    {
+      ::build2::build::cli::parser< string>::merge (
+        this->options_file_, a.options_file_);
+      this->options_file_specified_ = true;
+    }
+
+    if (a.default_options_specified_)
+    {
+      ::build2::build::cli::parser< dir_path>::merge (
+        this->default_options_, a.default_options_);
+      this->default_options_specified_ = true;
+    }
+
+    if (a.no_default_options_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->no_default_options_, a.no_default_options_);
+    }
+
+    if (a.help_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->help_, a.help_);
+    }
+
+    if (a.version_)
+    {
+      ::build2::build::cli::parser< bool>::merge (
+        this->version_, a.version_);
+    }
+  }
+
+  ::build2::build::cli::usage_para options::
+  print_usage (::std::ostream& os, ::build2::build::cli::usage_para p)
+  {
+    CLI_POTENTIALLY_UNUSED (os);
+
+    if (p != ::build2::build::cli::usage_para::none)
+      os << ::std::endl;
+
+    os << "\033[1mOPTIONS\033[0m" << ::std::endl;
+
+    os << std::endl
+       << "\033[1m-v\033[0m                    Print actual commands being executed. This options is" << ::std::endl
+       << "                      equivalent to \033[1m--verbose 2\033[0m." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m-V\033[0m                    Print all underlying commands being executed. This" << ::std::endl
+       << "                      options is equivalent to \033[1m--verbose 3\033[0m." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--quiet\033[0m|\033[1m-q\033[0m            Run quietly, only printing error messages in most" << ::std::endl
+       << "                      contexts. In certain contexts (for example, while" << ::std::endl
+       << "                      updating build system modules) this verbosity level may" << ::std::endl
+       << "                      be ignored. Use \033[1m--silent\033[0m to run quietly in all contexts." << ::std::endl
+       << "                      This option is equivalent to \033[1m--verbose 0\033[0m." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--silent\033[0m              Run quietly, only printing error messages in all" << ::std::endl
+       << "                      contexts." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--verbose\033[0m \033[4mlevel\033[0m       Set the diagnostics verbosity to \033[4mlevel\033[0m between 0 and 6." << ::std::endl
+       << "                      Level 0 disables any non-error messages (but see the" << ::std::endl
+       << "                      difference between \033[1m--quiet\033[0m and \033[1m--silent\033[0m) while level 6" << ::std::endl
+       << "                      produces lots of information, with level 1 being the" << ::std::endl
+       << "                      default. The following additional types of diagnostics" << ::std::endl
+       << "                      are produced at each level:" << ::std::endl
+       << ::std::endl
+       << "                      1. High-level information messages." << ::std::endl
+       << "                      2. Essential underlying commands being executed." << ::std::endl
+       << "                      3. All underlying commands being executed." << ::std::endl
+       << "                      4. Information that could be helpful to the user." << ::std::endl
+       << "                      5. Information that could be helpful to the developer." << ::std::endl
+       << "                      6. Even more detailed information." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--stat\033[0m                Display build statistics." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--dump\033[0m \033[4mphase\033[0m          Dump the build system state after the specified phase." << ::std::endl
+       << "                      Valid \033[4mphase\033[0m values are \033[1mload\033[0m (after loading \033[1mbuildfiles\033[0m)" << ::std::endl
+       << "                      and \033[1mmatch\033[0m (after matching rules to targets). Repeat this" << ::std::endl
+       << "                      option to dump the state after multiple phases." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--progress\033[0m            Display build progress. If printing to a terminal the" << ::std::endl
+       << "                      progress is displayed by default for low verbosity" << ::std::endl
+       << "                      levels. Use \033[1m--no-progress\033[0m to suppress." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--no-progress\033[0m         Don't display build progress." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--jobs\033[0m|\033[1m-j\033[0m \033[4mnum\033[0m         Number of active jobs to perform in parallel. This" << ::std::endl
+       << "                      includes both the number of active threads inside the" << ::std::endl
+       << "                      build system as well as the number of external commands" << ::std::endl
+       << "                      (compilers, linkers, etc) started but not yet finished." << ::std::endl
+       << "                      If this option is not specified or specified with the \033[1m0\033[0m" << ::std::endl
+       << "                      value, then the number of available hardware threads is" << ::std::endl
+       << "                      used." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--max-jobs\033[0m|\033[1m-J\033[0m \033[4mnum\033[0m     Maximum number of jobs (threads) to create. The default" << ::std::endl
+       << "                      is 8x the number of active jobs (\033[1m--jobs|j\033[0m) on 32-bit" << ::std::endl
+       << "                      architectures and 32x on 64-bit. See the build system" << ::std::endl
+       << "                      scheduler implementation for details." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--queue-depth\033[0m|\033[1m-Q\033[0m \033[4mnum\033[0m  The queue depth as a multiplier over the number of active" << ::std::endl
+       << "                      jobs. Normally we want a deeper queue if the jobs take" << ::std::endl
+       << "                      long (for example, compilation) and shorter if they are" << ::std::endl
+       << "                      quick (for example, simple tests). The default is 4. See" << ::std::endl
+       << "                      the build system scheduler implementation for details." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--file-cache\033[0m \033[4mimpl\033[0m     File cache implementation to use for intermediate build" << ::std::endl
+       << "                      results. Valid values are \033[1mnoop\033[0m (no caching or" << ::std::endl
+       << "                      compression) and \033[1msync-lz4\033[0m (no caching with synchronous" << ::std::endl
+       << "                      LZ4 on-disk compression). If this option is not" << ::std::endl
+       << "                      specified, then a suitable default implementation is used" << ::std::endl
+       << "                      (currently \033[1msync-lz4\033[0m)." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--max-stack\033[0m \033[4mnum\033[0m       The maximum stack size in KBytes to allow for newly" << ::std::endl
+       << "                      created threads. For \033[4mpthreads\033[0m-based systems the driver" << ::std::endl
+       << "                      queries the stack size of the main thread and uses the" << ::std::endl
+       << "                      same size for creating additional threads. This allows" << ::std::endl
+       << "                      adjusting the stack size using familiar mechanisms, such" << ::std::endl
+       << "                      as \033[1mulimit\033[0m. Sometimes, however, the stack size of the main" << ::std::endl
+       << "                      thread is excessively large. As a result, the driver" << ::std::endl
+       << "                      checks if it is greater than a predefined limit (64MB on" << ::std::endl
+       << "                      64-bit systems and 32MB on 32-bit ones) and caps it to a" << ::std::endl
+       << "                      more sensible value (8MB) if that's the case. This option" << ::std::endl
+       << "                      allows you to override this check with the special zero" << ::std::endl
+       << "                      value indicating that the main thread stack size should" << ::std::endl
+       << "                      be used as is." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--serial-stop\033[0m|\033[1m-s\033[0m      Run serially and stop at the first error. This mode is" << ::std::endl
+       << "                      useful to investigate build failures that are caused by" << ::std::endl
+       << "                      build system errors rather than compilation errors. Note" << ::std::endl
+       << "                      that if you don't want to keep going but still want" << ::std::endl
+       << "                      parallel execution, add \033[1m--jobs|-j\033[0m (for example \033[1m-j 0\033[0m for" << ::std::endl
+       << "                      default concurrency)." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--dry-run\033[0m|\033[1m-n\033[0m          Print commands without actually executing them. Note that" << ::std::endl
+       << "                      commands that are required to create an accurate build" << ::std::endl
+       << "                      state will still be executed and the extracted auxiliary" << ::std::endl
+       << "                      dependency information saved. In other words, this is not" << ::std::endl
+       << "                      the \033[4m\"don't touch the filesystem\"\033[0m mode but rather \033[4m\"do" << ::std::endl
+       << "                      minimum amount of work to show what needs to be done\"\033[0m." << ::std::endl
+       << "                      Note also that only the \033[1mperform\033[0m meta-operation supports" << ::std::endl
+       << "                      this mode." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--match-only\033[0m          Match the rules but do not execute the operation. This" << ::std::endl
+       << "                      mode is primarily useful for profiling." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--no-external-modules\033[0m Don't load external modules during project bootstrap." << ::std::endl
+       << "                      Note that this option can only be used with" << ::std::endl
+       << "                      meta-operations that do not load the project's" << ::std::endl
+       << "                      \033[1mbuildfiles\033[0m, such as \033[1minfo\033[0m." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--structured-result\033[0m   Write the result of execution in a structured form. In" << ::std::endl
+       << "                      this mode, instead of printing to \033[1mSTDERR\033[0m diagnostics" << ::std::endl
+       << "                      messages about the outcome of executing actions on" << ::std::endl
+       << "                      targets, the driver writes to \033[1mSTDOUT\033[0m a structured result" << ::std::endl
+       << "                      description one line per the buildspec action/target" << ::std::endl
+       << "                      pair. Each line has the following format:" << ::std::endl
+       << ::std::endl
+       << "                      \033[4mstate\033[0m \033[4mmeta-operation\033[0m \033[4moperation\033[0m \033[4mtarget\033[0m\033[0m" << ::std::endl
+       << ::std::endl
+       << "                      Where \033[4mstate\033[0m can be one of \033[1munchanged\033[0m, \033[1mchanged\033[0m, or \033[1mfailed\033[0m." << ::std::endl
+       << "                      If the action is a pre or post operation, then the outer" << ::std::endl
+       << "                      operation is specified in parenthesis. For example:" << ::std::endl
+       << ::std::endl
+       << "                      unchanged perform update(test) /tmp/dir{hello/}" << ::std::endl
+       << "                      changed perform test /tmp/dir{hello/}" << ::std::endl
+       << ::std::endl
+       << "                      Note that only the \033[1mperform\033[0m meta-operation supports the" << ::std::endl
+       << "                      structured result output." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--mtime-check\033[0m         Perform file modification time sanity checks. These" << ::std::endl
+       << "                      checks can be helpful in diagnosing spurious rebuilds and" << ::std::endl
+       << "                      are enabled by default on Windows (which is known not to" << ::std::endl
+       << "                      guarantee monotonically increasing mtimes) and for the" << ::std::endl
+       << "                      staged version of the build system on other platforms." << ::std::endl
+       << "                      Use \033[1m--no-mtime-check\033[0m to disable." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--no-mtime-check\033[0m      Don't perform file modification time sanity checks. See" << ::std::endl
+       << "                      \033[1m--mtime-check\033[0m for details." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--no-column\033[0m           Don't print column numbers in diagnostics." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--no-line\033[0m             Don't print line and column numbers in diagnostics." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--buildfile\033[0m \033[4mpath\033[0m      The alternative file to read build information from. The" << ::std::endl
+       << "                      default is \033[1mbuildfile\033[0m or \033[1mbuild2file\033[0m, depending on the" << ::std::endl
+       << "                      project's build file/directory naming scheme. If \033[4mpath\033[0m is" << ::std::endl
+       << "                      '\033[1m-\033[0m', then read from \033[1mSTDIN\033[0m. Note that this option only" << ::std::endl
+       << "                      affects the files read as part of the buildspec" << ::std::endl
+       << "                      processing. Specifically, it has no effect on the \033[1msource\033[0m" << ::std::endl
+       << "                      and \033[1minclude\033[0m directives. As a result, this option is" << ::std::endl
+       << "                      primarily intended for testing rather than changing the" << ::std::endl
+       << "                      build file names in real projects." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--config-guess\033[0m \033[4mpath\033[0m   The path to the \033[1mconfig.guess(1)\033[0m script that should be" << ::std::endl
+       << "                      used to guess the host machine triplet. If this option is" << ::std::endl
+       << "                      not specified, then \033[1mb\033[0m will fall back on to using the" << ::std::endl
+       << "                      target it was built for as host." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--config-sub\033[0m \033[4mpath\033[0m     The path to the \033[1mconfig.sub(1)\033[0m script that should be used" << ::std::endl
+       << "                      to canonicalize machine triplets. If this option is not" << ::std::endl
+       << "                      specified, then \033[1mb\033[0m will use its built-in canonicalization" << ::std::endl
+       << "                      support which should be sufficient for commonly-used" << ::std::endl
+       << "                      platforms." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--pager\033[0m \033[4mpath\033[0m          The pager program to be used to show long text. Commonly" << ::std::endl
+       << "                      used pager programs are \033[1mless\033[0m and \033[1mmore\033[0m. You can also" << ::std::endl
+       << "                      specify additional options that should be passed to the" << ::std::endl
+       << "                      pager program with \033[1m--pager-option\033[0m. If an empty string is" << ::std::endl
+       << "                      specified as the pager program, then no pager will be" << ::std::endl
+       << "                      used. If the pager program is not explicitly specified," << ::std::endl
+       << "                      then \033[1mb\033[0m will try to use \033[1mless\033[0m. If it is not available, then" << ::std::endl
+       << "                      no pager will be used." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--pager-option\033[0m \033[4mopt\033[0m    Additional option to be passed to the pager program. See" << ::std::endl
+       << "                      \033[1m--pager\033[0m for more information on the pager program. Repeat" << ::std::endl
+       << "                      this option to specify multiple pager options." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--options-file\033[0m \033[4mfile\033[0m   Read additional options from \033[4mfile\033[0m. Each option should" << ::std::endl
+       << "                      appear on a separate line optionally followed by space or" << ::std::endl
+       << "                      equal sign (\033[1m=\033[0m) and an option value. Empty lines and lines" << ::std::endl
+       << "                      starting with \033[1m#\033[0m are ignored. Option values can be" << ::std::endl
+       << "                      enclosed in double (\033[1m\"\033[0m) or single (\033[1m'\033[0m) quotes to preserve" << ::std::endl
+       << "                      leading and trailing whitespaces as well as to specify" << ::std::endl
+       << "                      empty values. If the value itself contains trailing or" << ::std::endl
+       << "                      leading quotes, enclose it with an extra pair of quotes," << ::std::endl
+       << "                      for example \033[1m'\"x\"'\033[0m. Non-leading and non-trailing quotes" << ::std::endl
+       << "                      are interpreted as being part of the option value." << ::std::endl
+       << ::std::endl
+       << "                      The semantics of providing options in a file is" << ::std::endl
+       << "                      equivalent to providing the same set of options in the" << ::std::endl
+       << "                      same order on the command line at the point where the" << ::std::endl
+       << "                      \033[1m--options-file\033[0m option is specified except that the shell" << ::std::endl
+       << "                      escaping and quoting is not required. Repeat this option" << ::std::endl
+       << "                      to specify more than one options file." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--default-options\033[0m \033[4mdir\033[0m The directory to load additional default options files" << ::std::endl
+       << "                      from." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--no-default-options\033[0m  Don't load default options files." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--help\033[0m                Print usage information and exit." << ::std::endl;
+
+    os << std::endl
+       << "\033[1m--version\033[0m             Print version and exit." << ::std::endl;
+
+    p = ::build2::build::cli::usage_para::option;
+
+    return p;
+  }
+
+  typedef
+  std::map<std::string, void (*) (options&, ::build2::build::cli::scanner&)>
+  _cli_options_map;
+
+  static _cli_options_map _cli_options_map_;
+
+  struct _cli_options_map_init
+  {
+    _cli_options_map_init ()
+    {
+      _cli_options_map_["--build2-metadata"] =
+      &::build2::build::cli::thunk< options, uint64_t, &options::build2_metadata_,
+        &options::build2_metadata_specified_ >;
+      _cli_options_map_["-v"] =
+      &::build2::build::cli::thunk< options, bool, &options::v_ >;
+      _cli_options_map_["-V"] =
+      &::build2::build::cli::thunk< options, bool, &options::V_ >;
+      _cli_options_map_["--quiet"] =
+      &::build2::build::cli::thunk< options, bool, &options::quiet_ >;
+      _cli_options_map_["-q"] =
+      &::build2::build::cli::thunk< options, bool, &options::quiet_ >;
+      _cli_options_map_["--silent"] =
+      &::build2::build::cli::thunk< options, bool, &options::silent_ >;
+      _cli_options_map_["--verbose"] =
+      &::build2::build::cli::thunk< options, uint16_t, &options::verbose_,
+        &options::verbose_specified_ >;
+      _cli_options_map_["--stat"] =
+      &::build2::build::cli::thunk< options, bool, &options::stat_ >;
+      _cli_options_map_["--dump"] =
+      &::build2::build::cli::thunk< options, std::set<string>, &options::dump_,
+        &options::dump_specified_ >;
+      _cli_options_map_["--progress"] =
+      &::build2::build::cli::thunk< options, bool, &options::progress_ >;
+      _cli_options_map_["--no-progress"] =
+      &::build2::build::cli::thunk< options, bool, &options::no_progress_ >;
+      _cli_options_map_["--jobs"] =
+      &::build2::build::cli::thunk< options, size_t, &options::jobs_,
+        &options::jobs_specified_ >;
+      _cli_options_map_["-j"] =
+      &::build2::build::cli::thunk< options, size_t, &options::jobs_,
+        &options::jobs_specified_ >;
+      _cli_options_map_["--max-jobs"] =
+      &::build2::build::cli::thunk< options, size_t, &options::max_jobs_,
+        &options::max_jobs_specified_ >;
+      _cli_options_map_["-J"] =
+      &::build2::build::cli::thunk< options, size_t, &options::max_jobs_,
+        &options::max_jobs_specified_ >;
+      _cli_options_map_["--queue-depth"] =
+      &::build2::build::cli::thunk< options, size_t, &options::queue_depth_,
+        &options::queue_depth_specified_ >;
+      _cli_options_map_["-Q"] =
+      &::build2::build::cli::thunk< options, size_t, &options::queue_depth_,
+        &options::queue_depth_specified_ >;
+      _cli_options_map_["--file-cache"] =
+      &::build2::build::cli::thunk< options, string, &options::file_cache_,
+        &options::file_cache_specified_ >;
+      _cli_options_map_["--max-stack"] =
+      &::build2::build::cli::thunk< options, size_t, &options::max_stack_,
+        &options::max_stack_specified_ >;
+      _cli_options_map_["--serial-stop"] =
+      &::build2::build::cli::thunk< options, bool, &options::serial_stop_ >;
+      _cli_options_map_["-s"] =
+      &::build2::build::cli::thunk< options, bool, &options::serial_stop_ >;
+      _cli_options_map_["--dry-run"] =
+      &::build2::build::cli::thunk< options, bool, &options::dry_run_ >;
+      _cli_options_map_["-n"] =
+      &::build2::build::cli::thunk< options, bool, &options::dry_run_ >;
+      _cli_options_map_["--match-only"] =
+      &::build2::build::cli::thunk< options, bool, &options::match_only_ >;
+      _cli_options_map_["--no-external-modules"] =
+      &::build2::build::cli::thunk< options, bool, &options::no_external_modules_ >;
+      _cli_options_map_["--structured-result"] =
+      &::build2::build::cli::thunk< options, bool, &options::structured_result_ >;
+      _cli_options_map_["--mtime-check"] =
+      &::build2::build::cli::thunk< options, bool, &options::mtime_check_ >;
+      _cli_options_map_["--no-mtime-check"] =
+      &::build2::build::cli::thunk< options, bool, &options::no_mtime_check_ >;
+      _cli_options_map_["--no-column"] =
+      &::build2::build::cli::thunk< options, bool, &options::no_column_ >;
+      _cli_options_map_["--no-line"] =
+      &::build2::build::cli::thunk< options, bool, &options::no_line_ >;
+      _cli_options_map_["--buildfile"] =
+      &::build2::build::cli::thunk< options, path, &options::buildfile_,
+        &options::buildfile_specified_ >;
+      _cli_options_map_["--config-guess"] =
+      &::build2::build::cli::thunk< options, path, &options::config_guess_,
+        &options::config_guess_specified_ >;
+      _cli_options_map_["--config-sub"] =
+      &::build2::build::cli::thunk< options, path, &options::config_sub_,
+        &options::config_sub_specified_ >;
+      _cli_options_map_["--pager"] =
+      &::build2::build::cli::thunk< options, string, &options::pager_,
+        &options::pager_specified_ >;
+      _cli_options_map_["--pager-option"] =
+      &::build2::build::cli::thunk< options, strings, &options::pager_option_,
+        &options::pager_option_specified_ >;
+      _cli_options_map_["--options-file"] =
+      &::build2::build::cli::thunk< options, string, &options::options_file_,
+        &options::options_file_specified_ >;
+      _cli_options_map_["--default-options"] =
+      &::build2::build::cli::thunk< options, dir_path, &options::default_options_,
+        &options::default_options_specified_ >;
+      _cli_options_map_["--no-default-options"] =
+      &::build2::build::cli::thunk< options, bool, &options::no_default_options_ >;
+      _cli_options_map_["--help"] =
+      &::build2::build::cli::thunk< options, bool, &options::help_ >;
+      _cli_options_map_["--version"] =
+      &::build2::build::cli::thunk< options, bool, &options::version_ >;
+    }
+  };
+
+  static _cli_options_map_init _cli_options_map_init_;
+
+  bool options::
+  _parse (const char* o, ::build2::build::cli::scanner& s)
+  {
+    _cli_options_map::const_iterator i (_cli_options_map_.find (o));
+
+    if (i != _cli_options_map_.end ())
+    {
+      (*(i->second)) (*this, s);
+      return true;
+    }
+
+    return false;
+  }
+
+  bool options::
+  _parse (::build2::build::cli::scanner& s,
+          ::build2::build::cli::unknown_mode opt_mode,
+          ::build2::build::cli::unknown_mode arg_mode)
+  {
+    // Can't skip combined flags (--no-combined-flags).
+    //
+    assert (opt_mode != ::build2::build::cli::unknown_mode::skip);
+
+    bool r = false;
+    bool opt = true;
+
+    while (s.more ())
+    {
+      const char* o = s.peek ();
+
+      if (std::strcmp (o, "--") == 0)
+      {
+        opt = false;
+      }
+
+      if (opt)
+      {
+        if (_parse (o, s))
+        {
+          r = true;
+          continue;
+        }
+
+        if (std::strncmp (o, "-", 1) == 0 && o[1] != '\0')
+        {
+          // Handle combined option values.
+          //
+          std::string co;
+          if (const char* v = std::strchr (o, '='))
+          {
+            co.assign (o, 0, v - o);
+            ++v;
+
+            int ac (2);
+            char* av[] =
+            {
+              const_cast<char*> (co.c_str ()),
+              const_cast<char*> (v)
+            };
+
+            ::build2::build::cli::argv_scanner ns (0, ac, av);
+
+            if (_parse (co.c_str (), ns))
+            {
+              // Parsed the option but not its value?
+              //
+              if (ns.end () != 2)
+                throw ::build2::build::cli::invalid_value (co, v);
+
+              s.next ();
+              r = true;
+              continue;
+            }
+            else
+            {
+              // Set the unknown option and fall through.
+              //
+              o = co.c_str ();
+            }
+          }
+
+          // Handle combined flags.
+          //
+          char cf[3];
+          {
+            const char* p = o + 1;
+            for (; *p != '\0'; ++p)
+            {
+              if (!((*p >= 'a' && *p <= 'z') ||
+                    (*p >= 'A' && *p <= 'Z') ||
+                    (*p >= '0' && *p <= '9')))
+                break;
+            }
+
+            if (*p == '\0')
+            {
+              for (p = o + 1; *p != '\0'; ++p)
+              {
+                std::strcpy (cf, "-");
+                cf[1] = *p;
+                cf[2] = '\0';
+
+                int ac (1);
+                char* av[] =
+                {
+                  cf
+                };
+
+                ::build2::build::cli::argv_scanner ns (0, ac, av);
+
+                if (!_parse (cf, ns))
+                  break;
+              }
+
+              if (*p == '\0')
+              {
+                // All handled.
+                //
+                s.next ();
+                r = true;
+                continue;
+              }
+              else
+              {
+                // Set the unknown option and fall through.
+                //
+                o = cf;
+              }
+            }
+          }
+
+          switch (opt_mode)
+          {
+            case ::build2::build::cli::unknown_mode::skip:
+            {
+              s.skip ();
+              r = true;
+              continue;
+            }
+            case ::build2::build::cli::unknown_mode::stop:
+            {
+              break;
+            }
+            case ::build2::build::cli::unknown_mode::fail:
+            {
+              throw ::build2::build::cli::unknown_option (o);
+            }
+          }
+
+          break;
+        }
+      }
+
+      switch (arg_mode)
+      {
+        case ::build2::build::cli::unknown_mode::skip:
+        {
+          s.skip ();
+          r = true;
+          continue;
+        }
+        case ::build2::build::cli::unknown_mode::stop:
+        {
+          break;
+        }
+        case ::build2::build::cli::unknown_mode::fail:
+        {
+          throw ::build2::build::cli::unknown_argument (o);
+        }
+      }
+
+      break;
+    }
+
+    return r;
+  }
+}
+
+namespace build2
+{
+  ::build2::build::cli::usage_para
+  print_b_usage (::std::ostream& os, ::build2::build::cli::usage_para p)
+  {
+    CLI_POTENTIALLY_UNUSED (os);
+
+    if (p != ::build2::build::cli::usage_para::none)
+      os << ::std::endl;
+
+    os << "\033[1mSYNOPSIS\033[0m" << ::std::endl
+       << ::std::endl
+       << "\033[1mb --help\033[0m" << ::std::endl
+       << "\033[1mb --version\033[0m" << ::std::endl
+       << "\033[1mb\033[0m [\033[4moptions\033[0m] [\033[4mvariables\033[0m] [\033[4mbuildspec\033[0m]\033[0m" << ::std::endl
+       << ::std::endl
+       << "\033[4mbuildspec\033[0m = \033[4mmeta-operation\033[0m\033[1m(\033[0m\033[4moperation\033[0m\033[1m(\033[0m\033[4mtarget\033[0m...[\033[1m,\033[0m\033[4mparameters\033[0m]\033[1m)\033[0m...\033[1m)\033[0m...\033[0m" << ::std::endl
+       << ::std::endl
+       << "\033[1mDESCRIPTION\033[0m" << ::std::endl
+       << ::std::endl
+       << "The \033[1mbuild2\033[0m build system driver executes a set of meta-operations on operations" << ::std::endl
+       << "on targets according to the build specification, or \033[4mbuildspec\033[0m for short.  This" << ::std::endl
+       << "process can be controlled by specifying driver \033[4moptions\033[0m and build system" << ::std::endl
+       << "\033[4mvariables\033[0m." << ::std::endl
+       << ::std::endl
+       << "Note that \033[4moptions\033[0m, \033[4mvariables\033[0m, and \033[4mbuildspec\033[0m fragments can be specified in any" << ::std::endl
+       << "order. To avoid treating an argument that starts with \033[1m'-'\033[0m as an option, add the" << ::std::endl
+       << "\033[1m'--'\033[0m separator. To avoid treating an argument that contains \033[1m'='\033[0m as a variable," << ::std::endl
+       << "add the second \033[1m'--'\033[0m separator." << ::std::endl;
+
+    p = ::build2::options::print_usage (os, ::build2::build::cli::usage_para::text);
+
+    if (p != ::build2::build::cli::usage_para::none)
+      os << ::std::endl;
+
+    os << "\033[1mDEFAULT OPTIONS FILES\033[0m" << ::std::endl
+       << ::std::endl
+       << "Instead of having a separate config file format for tool configuration, the" << ::std::endl
+       << "\033[1mbuild2\033[0m toolchain uses \033[4mdefault options files\033[0m which contain the same options as" << ::std::endl
+       << "what can be specified on the command line. The default options files are like" << ::std::endl
+       << "options files that one can specify with \033[1m--options-file\033[0m except that they are" << ::std::endl
+       << "loaded by default." << ::std::endl
+       << ::std::endl
+       << "The default options files for the build system driver are called \033[1mb.options\033[0m and" << ::std::endl
+       << "are searched for in the \033[1m.build2/\033[0m subdirectory of the home directory and in the" << ::std::endl
+       << "system directory (for example, \033[1m/etc/build2/\033[0m) if configured. Note that besides" << ::std::endl
+       << "options these files can also contain global variable overrides." << ::std::endl
+       << ::std::endl
+       << "Once the search is complete, the files are loaded in the reverse order, that" << ::std::endl
+       << "is, beginning from the system directory (if any), followed by the home" << ::std::endl
+       << "directory, and finishing off with the options specified on the command line. In" << ::std::endl
+       << "other words, the files are loaded from the more generic to the more specific" << ::std::endl
+       << "with the command line options having the ability to override any values" << ::std::endl
+       << "specified in the default options files." << ::std::endl
+       << ::std::endl
+       << "If a default options file contains \033[1m--no-default-options\033[0m, then the search is" << ::std::endl
+       << "stopped at the directory containing this file and no outer files are loaded. If" << ::std::endl
+       << "this option is specified on the command line, then none of the default options" << ::std::endl
+       << "files are searched for or loaded." << ::std::endl
+       << ::std::endl
+       << "An additional directory containing default options files can be specified with" << ::std::endl
+       << "\033[1m--default-options\033[0m. Its configuration files are loaded after the home directory." << ::std::endl
+       << ::std::endl
+       << "The order in which default options files are loaded is traced at the verbosity" << ::std::endl
+       << "level 3 (\033[1m-V\033[0m option) or higher." << ::std::endl
+       << ::std::endl
+       << "\033[1mEXIT STATUS\033[0m" << ::std::endl
+       << ::std::endl
+       << "Non-zero exit status is returned in case of an error." << ::std::endl;
+
+    os << std::endl
+       << "\033[1mENVIRONMENT\033[0m" << ::std::endl
+       << ::std::endl
+       << "The \033[1mHOME\033[0m environment variable is used to determine the user's home directory." << ::std::endl
+       << "If it is not set, then \033[1mgetpwuid(3)\033[0m is used instead. This value is used to" << ::std::endl
+       << "shorten paths printed in diagnostics by replacing the home directory with \033[1m~/\033[0m." << ::std::endl
+       << "It is also made available to \033[1mbuildfile\033[0m's as the \033[1mbuild.home\033[0m variable." << ::std::endl
+       << ::std::endl
+       << "The \033[1mBUILD2_VAR_OVR\033[0m environment variable is used to propagate global variable" << ::std::endl
+       << "overrides to nested build system driver invocations. Its value is a list of" << ::std::endl
+       << "global variable assignments separated with newlines." << ::std::endl
+       << ::std::endl
+       << "The \033[1mBUILD2_DEF_OPT\033[0m environment variable is used to suppress loading of default" << ::std::endl
+       << "options files in nested build system driver invocations. Its values are \033[1mfalse\033[0m" << ::std::endl
+       << "or \033[1m0\033[0m to suppress and \033[1mtrue\033[0m or \033[1m1\033[0m to load." << ::std::endl;
+
+    p = ::build2::build::cli::usage_para::text;
+
+    return p;
+  }
+}
+
+// Begin epilogue.
+//
+//
+// End epilogue.
+