From fc98bf23c16baf836d2c841792d4e0b35dd82727 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sat, 24 Mar 2018 13:27:35 +0200
Subject: Return bool from parse() indicating whether anything has been parsed

---
 cli/header.cxx  | 15 +++++++++++----
 cli/options.cxx | 13 ++++++++++---
 cli/options.hxx |  2 +-
 cli/source.cxx  | 41 +++++++++++++++++++++++++++++------------
 4 files changed, 51 insertions(+), 20 deletions(-)

diff --git a/cli/header.cxx b/cli/header.cxx
index de20334..64b31d2 100644
--- a/cli/header.cxx
+++ b/cli/header.cxx
@@ -136,9 +136,16 @@ namespace
 
         // Are we generating parsing constructors or parse() functions?
         //
-        string n (options.generate_parse ()
-                  ? string ("void\n") + (name != "parse" ? "parse" : "parse_")
-                  : name);
+        string n;
+        if (options.generate_parse ())
+        {
+          os << "// Return true if anything has been parsed." << endl
+             << "//" << endl;
+
+          n = string ("bool\n") + (name != "parse" ? "parse" : "parse_");
+        }
+        else
+          n = name;
 
         os << n << " (int& argc," << endl
            << "char** argv," << endl
@@ -247,7 +254,7 @@ namespace
       //
       if (!abst)
         os << "private:" << endl
-           << "void" << endl
+           << "bool" << endl
            << "_parse (" << cli << "::scanner&," << endl
            << um << " option," << endl
            << um << " argument);"
diff --git a/cli/options.cxx b/cli/options.cxx
index 0a9c0e4..149cc50 100644
--- a/cli/options.cxx
+++ b/cli/options.cxx
@@ -1866,11 +1866,12 @@ _parse (const char* o, ::cli::scanner& s)
   return false;
 }
 
-void options::
+bool options::
 _parse (::cli::scanner& s,
         ::cli::unknown_mode opt_mode,
         ::cli::unknown_mode arg_mode)
 {
+  bool r = false;
   bool opt = true;
 
   while (s.more ())
@@ -1879,12 +1880,14 @@ _parse (::cli::scanner& s,
 
     if (std::strcmp (o, "--") == 0)
     {
-      s.skip ();
       opt = false;
+      s.skip ();
+      r = true;
       continue;
     }
 
-    if (opt && _parse (o, s));
+    if (opt && _parse (o, s))
+      r = true;
     else if (opt && std::strncmp (o, "-", 1) == 0 && o[1] != '\0')
     {
       switch (opt_mode)
@@ -1892,6 +1895,7 @@ _parse (::cli::scanner& s,
         case ::cli::unknown_mode::skip:
         {
           s.skip ();
+          r = true;
           continue;
         }
         case ::cli::unknown_mode::stop:
@@ -1913,6 +1917,7 @@ _parse (::cli::scanner& s,
         case ::cli::unknown_mode::skip:
         {
           s.skip ();
+          r = true;
           continue;
         }
         case ::cli::unknown_mode::stop:
@@ -1928,6 +1933,8 @@ _parse (::cli::scanner& s,
       break;
     }
   }
+
+  return r;
 }
 
 // Begin epilogue.
diff --git a/cli/options.hxx b/cli/options.hxx
index a4242bc..8a93b43 100644
--- a/cli/options.hxx
+++ b/cli/options.hxx
@@ -1410,7 +1410,7 @@ class options
   _parse (const char*, ::cli::scanner&);
 
   private:
-  void
+  bool
   _parse (::cli::scanner&,
           ::cli::unknown_mode option,
           ::cli::unknown_mode argument);
diff --git a/cli/source.cxx b/cli/source.cxx
index 9c88014..37f0ef5 100644
--- a/cli/source.cxx
+++ b/cli/source.cxx
@@ -584,10 +584,16 @@ namespace
       if (!abst)
       {
         bool p (options.generate_parse ());
-        string n (
-          p
-          ? "void " + name + "::\n" + (name != "parse" ? "parse" : "parse_")
-          : name + "::\n" + name);
+
+        string n, res, ret;
+        if (p)
+        {
+          n = "bool " + name + "::\n" + (name != "parse" ? "parse" : "parse_");
+          res = "bool r = ";
+          ret = "return r;";
+        }
+        else
+          n = name + "::\n" + name;
 
         os << n << " (int& argc," << endl
            << "char** argv," << endl
@@ -602,7 +608,8 @@ namespace
         }
         os << "{"
            << cli << "::argv_scanner s (argc, argv, erase);"
-           << "_parse (s, opt, arg);"
+           << res << "_parse (s, opt, arg);"
+           << ret
            << "}";
 
         os << n << " (int start," << endl
@@ -619,7 +626,8 @@ namespace
         }
         os << "{"
            << cli << "::argv_scanner s (start, argc, argv, erase);"
-           << "_parse (s, opt, arg);"
+           << res << "_parse (s, opt, arg);"
+           << ret
            << "}";
 
         os << n << " (int& argc," << endl
@@ -636,8 +644,9 @@ namespace
         }
         os << "{"
            << cli << "::argv_scanner s (argc, argv, erase);"
-           << "_parse (s, opt, arg);"
+           << res << "_parse (s, opt, arg);"
            << "end = s.end ();"
+           << ret
            << "}";
 
         os << n << " (int start," << endl
@@ -655,8 +664,9 @@ namespace
         }
         os << "{"
            << cli << "::argv_scanner s (start, argc, argv, erase);"
-           << "_parse (s, opt, arg);"
+           << res << "_parse (s, opt, arg);"
            << "end = s.end ();"
+           << ret
            << "}";
 
         os << n << " (" << cli << "::scanner& s," << endl
@@ -669,7 +679,8 @@ namespace
           names (c, names_init);
         }
         os << "{"
-           << "_parse (s, opt, arg);"
+           << res << "_parse (s, opt, arg);"
+           << ret
            << "}";
       }
 
@@ -923,11 +934,12 @@ namespace
         bool pfx (!opt_prefix.empty ());
         bool sep (!opt_sep.empty ());
 
-        os << "void " << name << "::" << endl
+        os << "bool " << name << "::" << endl
            << "_parse (" << cli << "::scanner& s," << endl
            << um << (pfx ? " opt_mode" : "") << "," << endl
            << um << " arg_mode)"
-           << "{";
+           << "{"
+           << "bool r = false;";
 
         if (sep)
           os << "bool opt = true;" // Still recognizing options.
@@ -946,12 +958,14 @@ namespace
           if (!options.keep_separator ())
           {
             os << "s.skip ();" // We don't want to erase the separator.
+               << "r = true;"
                << "continue;";
           }
           os << "}";
         }
 
-        os << "if (" << (sep ? "opt && " : "") << "_parse (o, s));";
+        os << "if (" << (sep ? "opt && " : "") << "_parse (o, s))" << endl
+           << "r = true;";
 
         // Unknown option.
         //
@@ -972,6 +986,7 @@ namespace
              << "case " << cli << "::unknown_mode::skip:" << endl
              << "{"
              << "s.skip ();"
+             << "r = true;"
              << "continue;"
              << "}"
              << "case " << cli << "::unknown_mode::stop:" << endl
@@ -996,6 +1011,7 @@ namespace
            << "case " << cli << "::unknown_mode::skip:" << endl
            << "{"
            << "s.skip ();"
+           << "r = true;"
            << "continue;"
            << "}"
            << "case " << cli << "::unknown_mode::stop:" << endl
@@ -1011,6 +1027,7 @@ namespace
            << "}"
 
            << "}" // for
+           << "return r;"
            << "}";
       }
     }
-- 
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