Add the skeleton of the new client app.

lib/flags.h

@@ -0,0 +1,103 @@
+#ifndef FLAGS_H
+#define FLAGS_H
+
+class Flag
+{
+public:
+    static void parseFlags(int argc, const char* argv[]);
+
+    Flag(const std::vector<std::string>& names, const std::string helptext);
+    virtual ~Flag() {};
+
+    const std::string& name() const { return _names[0]; }
+    const std::vector<std::string> names() const { return _names; }
+    const std::string& helptext() const { return _helptext; }
+
+    virtual bool hasArgument() const = 0;
+    virtual const std::string defaultValue() const = 0;
+    virtual void set(const std::string value) = 0;
+
+private:
+    const std::vector<std::string> _names;
+    const std::string _helptext;
+};
+
+class ActionFlag : Flag
+{
+public:
+    ActionFlag(const std::vector<std::string>& names, const std::string helptext,
+            std::function<void(void)> callback):
+        Flag(names, helptext),
+        _callback(callback)
+    {}
+
+    bool hasArgument() const { return false; }
+    const std::string defaultValue() const { return ""; }
+    void set(const std::string value) { _callback(); }
+
+private:
+    const std::function<void(void)> _callback;
+};
+
+class SettableFlag : public Flag
+{
+public:
+    SettableFlag(const std::vector<std::string>& names, const std::string helptext):
+        Flag(names, helptext)
+    {}
+
+    operator bool() const { return _value; }
+
+    bool hasArgument() const { return false; }
+    const std::string defaultValue() const { return "false"; }
+    void set(const std::string value) { _value = true; }
+
+private:
+    bool _value = false;
+};
+
+template <typename T>
+class ValueFlag : public Flag
+{
+public:
+    ValueFlag(const std::vector<std::string>& names, const std::string helptext,
+            const T defaultValue):
+        Flag(names, helptext),
+        _defaultValue(defaultValue),
+        _value(defaultValue)
+    {}
+
+    operator T() const { return _value; }
+
+    bool hasArgument() const { return true; }
+
+protected:
+    T _defaultValue;
+    T _value;
+};
+
+class StringFlag : public ValueFlag<std::string>
+{
+public:
+    StringFlag(const std::vector<std::string>& names, const std::string helptext,
+            const std::string defaultValue = ""):
+        ValueFlag(names, helptext, defaultValue)
+    {}
+
+    const std::string defaultValue() const { return _defaultValue; }
+    void set(const std::string value) { _value = value; }
+};
+
+class IntFlag : public ValueFlag<int>
+{
+public:
+    IntFlag(const std::vector<std::string>& names, const std::string helptext,
+            int defaultValue = 0):
+        ValueFlag(names, helptext, defaultValue)
+    {}
+
+    const std::string defaultValue() const { return std::to_string(_defaultValue); }
+    void set(const std::string value) { _value = std::stoi(value); }
+};
+
+#endif