Add --regexp and --input, add both as positional options.

src/main.cpp

@@ -24,6 +24,8 @@
 #include <exception>
 #include <iostream>
 #include <locale>
+#include <string>
+#include <vector>
 
 int main(int argc, char *argv[])
 {
@@ -58,4 +60,14 @@ int main(int argc, char *argv[])
     cout << "extended-regexp: " << vm.count("extended-regexp") << '\n';
     cout << "perl-regexp: " << vm.count("perl-regexp") << '\n';
     cout << "ignore-case: " << vm.count("ignore-case") << '\n';
+
+    if (vm.count("input") > 0)
+    {
+        cout << "\nINPUT FILES: ";
+        for (const auto &input : vm["input"].as<std::vector<std::string>>())
+        {
+            cout << input << " ";
+        }
+        cout << '\n';
+    }
 }

src/options.cpp

@@ -22,6 +22,8 @@
 #include <boost/locale/message.hpp>
 #include <boost/program_options/options_description.hpp>
 #include <boost/program_options/parsers.hpp>
+#include <boost/program_options/positional_options.hpp>
+#include <boost/program_options/value_semantic.hpp>
 #include <boost/program_options/variables_map.hpp>
 
 #include <cstdlib>
@@ -39,35 +41,48 @@ using std::cout;
 
 po::variables_map parse_options(int argc, char *argv[])
 {
-    po::options_description desc(translate("Available options"));
+    po::options_description cmdline_desc(translate("Available options"));
     // clang-format off
-    desc.add_options()
+    cmdline_desc.add_options()
         ("help",
-         translate("Display this help and exit").str().data())
+         translate("Display this help and exit.").str().data())
         ("version",
-         translate("Display version information and exit").str().data())
+         translate("Display version information and exit.").str().data())
         ("extended-regexp",
-         translate("PATTERNS are extended regular expressions").str().data())
+         translate("PATTERN is extended regular expression.").str().data())
         ("perl-regexp",
-         translate("PATTERNS are Perl regular expressions").str().data())
+         translate("PATTERN is Perl regular expression.").str().data())
         ("ignore-case",
-         translate("Ignore case distinctions in patterns and data")
+         translate("Ignore case distinctions in pattern and data.")
          .str().data())
+        ("regexp", po::value<std::string>()->value_name(translate("PATTERN")),
+         translate("Use PATTERN for matching.").str().data())
+        ("input", po::value<std::vector<std::string>>()
+         ->value_name(translate("FILE")),
+         translate("Input files. Can be repeated.").str().data())
     ;
     // clang-format on
+
+    po::positional_options_description positional_desc;
+    positional_desc.add("regexp", 1).add("input", -1);
+
     po::variables_map vm;
-    po::store(po::parse_command_line(argc, argv, desc), vm);
+    po::store(po::command_line_parser(argc, argv)
+                  .options(cmdline_desc)
+                  .positional(positional_desc)
+                  .run(),
+              vm);
 
     std::ifstream configfile(get_config_path());
-    po::store(po::parse_config_file(configfile, desc, true), vm);
+    po::store(po::parse_config_file(configfile, cmdline_desc, true), vm);
     configfile.close();
 
     po::notify(vm);
 
     if (vm.count("help") != 0)
     {
-        cout << translate("Usage: epubgrep [OPTION]… PATTERNS [FILE]…\n");
+        cout << translate("Usage: epubgrep [OPTION]… PATTERN [FILE]…\n");
-        cout << desc;
+        cout << cmdline_desc;
     }
     else if (vm.count("version") != 0)
     {