add command line options

src/meson.build

@@ -1,3 +1,10 @@
+conf_data = configuration_data()
+conf_data.set('version', meson.project_version())
+configure_file(input : 'version.h.in',
+    output : 'version.h',
+    configuration : conf_data
+)
+
 obelisk_sources = files(
     'obelisk.cpp',
     'lexer.cpp',

src/obelisk.cpp

@@ -2,6 +2,7 @@
 #include "lexer.h"
 #include "obelisk.h"
 #include "parser.h"
+#include "version.h"
 
 #include <iomanip>
 #include <iostream>
@@ -73,38 +74,62 @@ static int obelisk::mainLoop()
     return EXIT_SUCCESS;
 }
 
+void obelisk::showUsage()
+{
+    std::cout << obelisk::usageMessage << std::endl;
+}
+
 int main(int argc, char** argv)
 {
-    for (int i = 1; i < argc; i++)
+    std::vector<std::string> sourceFiles;
+    std::string kbFile = "obelisk.kb";
+
+    while (true)
     {
-        std::cout << argv[i] << std::endl;
+        int option_index = 0;
+        switch (getopt_long(argc, argv, "k:hv", obelisk::long_options, &option_index))
+        {
+            case 'k' :
+                kbFile = std::string(optarg);
+                continue;
+            case 'h' :
+                obelisk::showUsage();
+                return EXIT_SUCCESS;
+                break;
+            case 'v' :
+                std::cout << "obelisk " << obelisk::version << std::endl;
+                return EXIT_SUCCESS;
+                break;
+            default :
+                obelisk::showUsage();
+                return EXIT_FAILURE;
+                break;
+
+            case -1 :
+                break;
+        }
+
+        break;
     }
 
-    // This can be used to store a double as 2 floats in the database, then restore it back to a double.
-    // Inspired by Godot's double precision on the GPU to render large worlds.
-    /*try
+    if (optind < argc)
     {
-        float first;
-        float second;
-        double var = 0.123456789012345;
-
-        obelisk::KnowledgeBase* kb = new obelisk::KnowledgeBase("cromer.kb");
-        kb->getFloat(first, second, var);
-        std::cout << std::setprecision(std::numeric_limits<double>::digits10)
-                  << "Double: " << var << std::endl
-                  << "First: " << first << std::endl
-                  << "Second: " << second << std::endl;
-        var = 0.0;
-        kb->getDouble(var, first, second);
-        std::cout << std::setprecision(std::numeric_limits<double>::digits10)
-                  << "Double: " << var << std::endl
-                  << "First: " << first << std::endl
-                  << "Second: " << second << std::endl;
+        while (optind < argc)
+        {
+            sourceFiles.push_back(argv[optind++]);
+        }
     }
-    catch (obelisk::KnowledgeBaseException& exception)
+
+    if (sourceFiles.size() == 0)
     {
+        obelisk::showUsage();
         return EXIT_FAILURE;
-    }*/
+    }
+
+    std::cout << sourceFiles[0] << std::endl;
+    std::cout << kbFile << std::endl;
+
+    return 0;
 
     return obelisk::mainLoop();
 }

src/obelisk.h

@@ -1,10 +1,41 @@
+#include <getopt.h>
+
 /**
- * @brief The obelisk namespace contains everything needed to compile obelisk
+ * @brief The obelisk namespace contains everything needed to compile obelisk.
  * code.
  *
  */
 namespace obelisk
 {
+    /**
+     * @brief The usage messsage displayed during help or incorrect usage.
+     *
+     */
+    std::string usageMessage = R"(Usage: obelisk [OPTION]... [FILE]...
+Compile the obelisk source FILE(s) into knoweldge base and library.
+
+Options:
+  -h, --help            shows this help/usage message
+  -k, --kb=FILENAME     output knowldege base filename
+  -v, --version         shows the version of obelisk)";
+
+    /**
+     * @brief The command line arguments that obelisk accepts.
+     *
+     */
+    static struct option long_options[] = {
+        {"help",    no_argument,       0, 'h'},
+        {"kb",      required_argument, 0, 'k'},
+        {"version", no_argument,       0, 'v'},
+        {0,         0,                 0, 0  }
+    };
+
+    /**
+     * @brief Prints out the usage of obelisk to the stdin.
+     *
+     */
+    static void showUsage();
+
     /**
      * @brief This is the main loop for obelisk.
      * This loop handles lexing and parsing of obelisk source code.

src/version.h.in

@@ -0,0 +1,8 @@
+namespace obelisk
+{
+    /**
+     * @brief The current version of obelisk.
+     *
+     */
+    std::string version = "@version@";
+} // namespace obelisk