Add simple CLI skeleton implementation

Signed-off-by: Cristian Le <cristian.le@mpsd.mpg.de>

src/CMakeLists.txt

@@ -6,13 +6,17 @@ target_sources(nlohmann_json_schema_validator PRIVATE
         json-patch.cpp
         string-format-check.cpp
         )
+target_sources(nlohmann_json_schema_validator_cli PRIVATE
+        cli.cpp)
+
 target_include_directories(nlohmann_json_schema_validator PUBLIC
         $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
         $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
         )
-
 set_target_properties(nlohmann_json_schema_validator PROPERTIES
         PUBLIC_HEADER nlohmann/json-schema.hpp)
+target_link_libraries(nlohmann_json_schema_validator_cli PRIVATE
+        nlohmann_json_schema_validator CLI11::CLI11)
 
 # TODO: Why would this need to be if guarded?
 if (JSON_VALIDATOR_SHARED_LIBS)

src/cli.cpp

@@ -0,0 +1,17 @@
+#include <CLI/App.hpp>
+#include <CLI/Config.hpp>
+#include <CLI/Formatter.hpp>
+
+int main(int argc, char *argv[])
+{
+	CLI::App app{"Json schema validator", "json-validator"};
+	// TODO: Move to a generated header file
+	app.set_version_flag("--version", "2.2.0");
+
+	try {
+		app.parse(argc, argv);
+	} catch (const CLI::ParseError &e) {
+		return app.exit(e);
+	}
+	return 0;
+}