Pros of Folly

• Designed for modern C++ (C++14 and later), offering more up-to-date features and optimizations
• Focuses on high-performance components, particularly useful for large-scale applications
• Includes unique utilities like FBString and Futures, which are not available in Boost

Cons of Folly

• Smaller community and ecosystem compared to Boost's long-established presence
• Less comprehensive documentation and fewer learning resources available
• More specialized focus, potentially less suitable for general-purpose C++ development

Code Comparison

Boost example (using shared_ptr):

#include <boost/shared_ptr.hpp>

boost::shared_ptr<int> ptr(new int(42));

Folly example (using fbstring):

#include <folly/FBString.h>

folly::fbstring str = "Hello, Folly!";

Both libraries offer powerful utilities, but Folly tends to focus on performance-critical scenarios, while Boost provides a broader range of general-purpose components. Folly's modern C++ approach may appeal to developers working on cutting-edge projects, while Boost's extensive history and wide adoption make it a reliable choice for many C++ developers across various domains.

Pros of Abseil

• Designed for modern C++ (C++11 and later), offering more up-to-date features and practices
• Lightweight and modular, allowing for easier integration into existing projects
• Maintained by Google, ensuring regular updates and support

Cons of Abseil

• Smaller community and ecosystem compared to Boost
• Less comprehensive in terms of overall functionality and library breadth
• Relatively newer, with potentially fewer resources and third-party integrations

Code Comparison

Abseil (string manipulation):

#include "absl/strings/str_cat.h"
std::string result = absl::StrCat("Hello, ", name, "!");

Boost (string manipulation):

#include <boost/algorithm/string.hpp>
std::string result = boost::algorithm::join({"Hello, ", name, "!"}, "");

Both libraries offer powerful utilities, but Abseil's syntax is often more concise and modern. Boost provides a wider range of functionalities, while Abseil focuses on core components with a more streamlined approach. The choice between them depends on project requirements, C++ version compatibility, and personal preferences.

Pros of GSL

• Lightweight and focused on core guidelines, making it easier to integrate into projects
• Modern C++ design with a strong emphasis on safety and correctness
• Faster compilation times due to its smaller codebase

Cons of GSL

• Limited scope compared to Boost's extensive library collection
• Less mature and battle-tested than Boost
• Smaller community and ecosystem support

Code Comparison

GSL:

#include <gsl/gsl>

void example(gsl::span<int> arr) {
    for (int& i : arr) {
        i *= 2;
    }
}

Boost:

#include <boost/range/adaptor/transformed.hpp>

void example(std::vector<int>& vec) {
    auto doubled = vec | boost::adaptors::transformed([](int i) { return i * 2; });
    vec.assign(doubled.begin(), doubled.end());
}

Summary

GSL focuses on implementing C++ Core Guidelines, providing a lightweight alternative to Boost for specific use cases. It offers modern C++ design and faster compilation but lacks the extensive feature set and maturity of Boost. GSL is ideal for projects prioritizing safety and correctness, while Boost remains the go-to choice for comprehensive C++ library needs.

Pros of fmt

• Lightweight and focused solely on formatting, making it easier to integrate and use
• Modern C++ design with a clean, intuitive API
• Faster compilation times due to its smaller codebase

Cons of fmt

• Limited scope compared to Boost's extensive feature set
• Less widespread adoption and community support
• Fewer platform-specific optimizations

Code Comparison

fmt:

#include <fmt/core.h>

std::string s = fmt::format("Hello, {}!", "world");
fmt::print("The answer is {}.", 42);

Boost:

#include <boost/format.hpp>

std::string s = boost::str(boost::format("Hello, %1%!") % "world");
std::cout << boost::format("The answer is %1%.") % 42;

Both libraries provide formatting capabilities, but fmt offers a more streamlined and modern syntax. Boost's Format library is part of a larger ecosystem, which can be beneficial for projects already using other Boost components. fmt focuses solely on formatting, making it a lighter alternative for projects that don't require Boost's full feature set.

Pros of GoogleTest

• Focused specifically on unit testing, making it more lightweight and easier to integrate
• Extensive documentation and examples, simplifying the learning curve
• Built-in support for parameterized tests and test fixtures

Cons of GoogleTest

• Limited to C++ testing, while Boost offers a broader range of utilities
• Less comprehensive than Boost's test framework, which includes additional features like runtime monitoring

Code Comparison

GoogleTest:

TEST(FactorialTest, HandlesZeroInput) {
  EXPECT_EQ(Factorial(0), 1);
}

Boost:

BOOST_AUTO_TEST_CASE(factorial_test) {
  BOOST_CHECK_EQUAL(factorial(0), 1);
}

Both libraries provide similar syntax for writing unit tests, but GoogleTest's approach is slightly more readable and intuitive for beginners. Boost's test framework, however, offers more advanced features and is part of a larger ecosystem of C++ utilities.

While GoogleTest excels in its focused approach to unit testing, Boost provides a more comprehensive suite of tools for C++ development. The choice between the two depends on project requirements and whether additional Boost libraries are needed.

Pros of json

• Lightweight and focused solely on JSON handling
• Header-only library, easy to integrate into projects
• Modern C++ design with intuitive API

Cons of json

• Limited scope compared to Boost's extensive feature set
• Lacks the broad community support and long-standing reputation of Boost
• May not be as performant for large-scale JSON operations

Code Comparison

json:

#include <nlohmann/json.hpp>
using json = nlohmann::json;

json j = {
  {"name", "John"},
  {"age", 30},
  {"city", "New York"}
};
std::string s = j.dump();

Boost (using property_tree for JSON):

#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
namespace pt = boost::property_tree;

pt::ptree root;
root.put("name", "John");
root.put("age", 30);
root.put("city", "New York");
std::stringstream ss;
pt::write_json(ss, root);

The json library offers a more straightforward and modern approach to JSON handling, while Boost provides a more general-purpose solution within its extensive ecosystem of C++ libraries.