Added optional method chained interface

contrib/chained/README.md

+# Method Chained libconfig #
+
+**Exception free + header only + method chained + config files**
+
+Provides reading the configuration and defining the configuration specification at once.
+
+### Features ###
+
+ * default values
+ * limits (min/max)
+ * mandatory/optional values
+ * help text output for expected config format on specification violation
+ * capturing and outputting expected configuration specification/defaults
+
+While it is possible to write a config file with this extension using the configuration specification capturing feature, it is not intended to be used as a full fledged config writer.
+
+### Example ###
+
+```C++
+#include <libconfig_chained.h>
+
+using namespace std;
+using namespace libconfig;
+
+int main(int argc, char **argv)
+{
+    Config cfg;
+    cfg.readFile("example.cfg");
+    ChainedSetting cs(cfg.getRoot());
+
+    string name = cs["name"].defaultValue("<name>").isMandatory();
+    string abstract = cs["abstract"].defaultValue("<unknown>");
+    double longitude = cs["longitude"].min(-180.0).max(180.0).isMandatory();
+    double latitude = cs["latitude"].min(-90.0).max(90.0).isMandatory();
+
+    if (cs.isAnyMandatorySettingMissing())
+    {
+        cerr << "Cannot proceed until all mandatory settings are set." << endl;
+    }
+}
+```
+
+Console Output:
+```sh
+'longitude' setting is out of valid bounds (max: 180). Value was: 1200.35
+Missing 'latitude' setting in configuration file.
+Cannot proceed until all mandatory settings are set.
+```
+
+---
+
+### How to integrate into your project ###
+
+ 1. Link the libconfig++.[lib/la/a] library as usual (see standard use of libconfig++).
+ * Replace any includes of libconfig.h++ by libconfig_chained.h.
+ * Use method chained candy as displayed above.
+
+---
+
+Create an issue for any questions or suggestions. Alternatively email me at github [at) hemofektik.de
\ No newline at end of file

contrib/chained/examples/CMakeLists.txt

+cmake_minimum_required(VERSION 2.8)
+
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY  "${CMAKE_SOURCE_DIR}/")
+
+project (ChainedLibconfigExample)
+file(GLOB SOURCES *.cpp *.h ../*.h ../*.md)
+
+if(MSVC)
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MP")
+else()
+	find_package(libconfig)
+endif()
+
+if(CMAKE_COMPILER_IS_GNUCXX)
+	#set(CMAKE_BUILD_TYPE Debug)
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+endif()
+
+include_directories(
+	${CMAKE_SOURCE_DIR}/../../../lib/
+)
+
+if(MSVC)
+ link_libraries (
+    ${CMAKE_SOURCE_DIR}/../../../Debug/libconfig++.lib
+ )
+else()
+link_libraries (
+	${LIBCONFIG_LIBRARY}
+)
+endif()
+
+
+add_executable (
+   ChainedLibconfigExample
+#   WIN32 # Only if you don't want the DOS prompt to appear in the background in Windows
+#   MACOSX_BUNDLE
+   ${SOURCES} # We could've listed the source files here directly instead of using a variable to store them
+   #${INCLUDES}
+)

contrib/chained/examples/CreateProjectFiles.bat

+@echo off
+rmdir sln /S/Q
+mkdir sln
+cd sln
+cmake -G "Visual Studio 15 2017" ..
+
+pause
\ No newline at end of file

contrib/chained/examples/README.md

+
+### Running the examples ###
+
+Expected Console Output:
+
+```C++
+<<< Example 1 >>>
+
+'longitude' setting is out of valid bounds (max: 180). Value was: 1200.35
+Missing 'latitude' setting in configuration file.
+Cannot proceed until all mandatory settings are set.
+
+
+<<< Example 2 >>>
+
+TITLE                           AUTHOR                           PRICE   QTY
+Treasure Island                 Robert Louis Stevenson          $ 29.99  5
+Snow Crash                      Neal Stephenson                 $  9.99  8
+
+
+<<< Example 3 >>>
+
+'longitude' setting is out of valid bounds (max: 180). Value was: 1200.35
+Missing 'latitude' setting in configuration file.
+Cannot proceed until all mandatory settings are set.
+
+Expected Config Layout:
+
+// -- begin --
+name = "<name>";
+abstract = "<unknown>";
+longitude = 0.0;
+latitude = 0.0;
+inventory =
+{
+   movies = ( );
+   books = (
+      {
+         title = "bookXYZ";
+      } );
+};
+// --- end ---
+```
\ No newline at end of file

contrib/chained/examples/example.cfg

+// An example configuration file that stores information about a store.
+
+// Basic store information:
+name = "Books, Movies & More";
+longitude = 1200.345678;
+
+// Store inventory:
+inventory =
+{
+  books = ( { title  = "Treasure Island";
+              author = "Robert Louis Stevenson";
+              price  = 29.99;
+              qty    = 5; },
+            { title  = "Snow Crash";
+              author = "Neal Stephenson";
+              price  = 9.99;
+              qty    = 8; },
+            { title  = "Das Kapital";
+              price  = 0.0;
+              qty    = 100000; }
+          );
+
+  movies = ( { title = "Brazil";
+               media = "DVD";
+               price = 19.99;
+               qty = 11; },
+             { title = "The City of Lost Children";
+               media = "DVD";
+               price = 18.99;
+               qty = 5; },
+             { title = "Memento";
+               media = "Blu-Ray";
+               price = 24.99;
+               qty = 20;
+             },
+             { title = "Howard the Duck"; }
+           );
+};
+
+// Store hours:
+hours =
+{
+  mon = { open =  9; close = 18; };
+  tue = { open =  9; close = 18; };
+  wed = { open =  9; close = 18; };
+  thu = { open =  9; close = 18; };
+  fri = { open =  9; close = 20; };
+  sat = { open =  9; close = 20; };
+  sun = { open = 11; close = 16; };
+};
+
+lost_bag = ( 1234.5678, "Napkin", [1, 2, 3] );

contrib/chained/examples/example1.cpp

+/* ----------------------------------------------------------------------------
+   libconfig - A library for processing structured configuration files
+   libconfig chained - Extension for reading the configuration and defining 
+                       the configuration specification at once.
+   Copyright (C) 2016 Richard Schubert
+
+   This file is part of libconfig contributions.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License
+   as published by the Free Software Foundation; either version 2.1 of
+   the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, see
+   <http://www.gnu.org/licenses/>.
+   ----------------------------------------------------------------------------
+*/
+
+#include <iostream>
+#include <iomanip>
+#include <cstdlib>
+#include "../libconfig_chained.h"
+
+using namespace std;
+using namespace libconfig;
+
+// This example reads basic information from config file 
+// and reacts on missing mandatory values.
+
+void example1(Config& cfg)
+{
+	ChainedSetting cs(cfg.getRoot());
+
+	string name = cs["name"].defaultValue("<name>").isMandatory();
+	string abstract = cs["abstract"].defaultValue("<unknown>");
+	double longitude = cs["longitude"].min(-180.0).max(180.0).isMandatory();
+	double latitude = cs["latitude"].min(-90.0).max(90.0).isMandatory();
+
+	if (cs.isAnyMandatorySettingMissing())
+	{
+		cerr << "Cannot proceed until all mandatory settings are set." << endl;
+		return;
+	}
+
+	// from here on all read config values are valid
+}

contrib/chained/examples/example2.cpp

+/* ----------------------------------------------------------------------------
+   libconfig - A library for processing structured configuration files
+   libconfig chained - Extension for reading the configuration and defining 
+                       the configuration specification at once.
+   Copyright (C) 2016 Richard Schubert
+
+   This file is part of libconfig contributions.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License
+   as published by the Free Software Foundation; either version 2.1 of
+   the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, see
+   <http://www.gnu.org/licenses/>.
+   ----------------------------------------------------------------------------
+*/
+
+#include <iostream>
+#include <iomanip>
+#include <cstdlib>
+#include "../libconfig_chained.h"
+
+using namespace std;
+using namespace libconfig;
+
+// This example reads complex types from config file using method chains.
+
+void example2(Config& cfg)
+{
+	ChainedSetting cs(cfg.getRoot());
+
+	auto books = cs["inventory"]["books"];
+	if (!books.exists())
+	{
+		cerr << "No book section available." << endl;
+		return;
+	}
+
+	cout << setw(30) << left << "TITLE" << "  "
+			<< setw(30) << left << "AUTHOR" << "   "
+			<< setw(6) << left << "PRICE" << "  "
+			<< "QTY"
+			<< endl;
+
+	const int count = books.getLength();
+	for(int i = 0; i < count; ++i)
+	{
+		auto book = books[i];
+
+		string title = book["title"];
+		string author = book["author"];
+		double price = book["price"].min(0.0);
+		int qty = book["qty"].min(0);
+
+		// Only output the record if all of the expected fields are present.
+		if(book.isAnySettingMissing()) continue;
+
+		cout << setw(30) << left << title << "  "
+			<< setw(30) << left << author << "  "
+			<< '$' << setw(6) << right << price << "  "
+			<< qty
+			<< endl;
+	}
+}

contrib/chained/examples/example3.cpp

+/* ----------------------------------------------------------------------------
+   libconfig - A library for processing structured configuration files
+   libconfig chained - Extension for reading the configuration and defining 
+                       the configuration specification at once.
+   Copyright (C) 2016 Richard Schubert
+
+   This file is part of libconfig contributions.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License
+   as published by the Free Software Foundation; either version 2.1 of
+   the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, see
+   <http://www.gnu.org/licenses/>.
+   ----------------------------------------------------------------------------
+*/
+
+#include <iostream>
+#include <iomanip>
+#include <cstdlib>
+#include "../libconfig_chained.h"
+
+using namespace std;
+using namespace libconfig;
+
+// This example reads basic information from config file 
+// and prints out the expected configuration specification.
+
+void example3(Config& cfg)
+{
+	ChainedSetting cs(cfg.getRoot());
+
+	Config tmpCfgSpec;
+	tmpCfgSpec.setOptions(Config::OptionOpenBraceOnSeparateLine | Config::OptionSemicolonSeparators);
+	tmpCfgSpec.setTabWidth(3);
+	cs.captureExpectedSpecification(&tmpCfgSpec);
+
+	string name = cs["name"].defaultValue("<name>").isMandatory();
+	string abstract = cs["abstract"].defaultValue("<unknown>");
+	double longitude = cs["longitude"].min(-180.0).max(180.0).isMandatory();
+	double latitude = cs["latitude"].min(-90.0).max(90.0).isMandatory();
+
+	ChainedSetting movie0 = cs["inventory"]["movies"][0];
+	string book0tile = cs["inventory"]["books"][0]["title"].defaultValue("bookXYZ");
+
+	if (cs.isAnyMandatorySettingMissing())
+	{
+		cerr << "Cannot proceed until all mandatory settings are set." << endl << endl;
+
+		auto cfgSpec = cs.getCapturedSpecification("tmpCfgSpec.cfg");
+		cerr << "Expected Config Layout: " << endl << endl;
+		cerr << "// -- begin --" << endl;
+		cerr << cfgSpec;
+		cerr << "// --- end ---" << endl << endl;
+		return;
+	}
+
+	// from here on all read config values are valid
+}

contrib/chained/examples/examples.cpp

+/* ----------------------------------------------------------------------------
+   libconfig - A library for processing structured configuration files
+   libconfig chained - Extension for reading the configuration and defining 
+                       the configuration specification at once.
+   Copyright (C) 2016 Richard Schubert
+
+   This file is part of libconfig contributions.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License
+   as published by the Free Software Foundation; either version 2.1 of
+   the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, see
+   <http://www.gnu.org/licenses/>.
+   ----------------------------------------------------------------------------
+*/
+
+#include <iostream>
+#include <iomanip>
+#include <cstdlib>
+#include <libconfig.h++>
+
+using namespace std;
+using namespace libconfig;
+
+// This is the main entry point for all examples.
+// The examples will be called consecutively. 
+
+void example1(Config& cfg);
+void example2(Config& cfg);
+void example3(Config& cfg);
+
+int main(int argc, char **argv)
+{
+  Config cfg;
+
+  // Read the file. If there is an error, report it and exit.
+  try
+  {
+    cfg.readFile("../example.cfg");
+  }
+  catch(const FileIOException&)
+  {
+    std::cerr << "I/O error while reading file. " << std::endl;
+    return(EXIT_FAILURE);
+  }
+  catch(const ParseException& pex)
+  {
+    std::cerr << "Parse error at " << pex.getFile() << ":" << pex.getLine()
+              << " - " << pex.getError() << std::endl;
+    return(EXIT_FAILURE);
+  }
+
+  cout << endl << endl << "<<< Example 1 >>>" << endl << endl;
+  example1(cfg);
+  cout << endl << endl << "<<< Example 2 >>>" << endl << endl;
+  example2(cfg);
+  cout << endl << endl << "<<< Example 3 >>>" << endl << endl;
+  example3(cfg);
+
+  return(EXIT_SUCCESS);
+}