How advanced C++ developers wrote modern code before the rise of modern standards.

Before the advent of C++11 and subsequent standards, advanced C++ developers had to innovate to write modern, maintainable, and efficient code. Here are some examples of how they proceeded with features that were later standardized:

1- shared_ptr

Smart pointers in C++ have been used for a long time, often through custom implementations or libraries like Boost. For many C++ developers, the introduction of shared_ptr and other smart pointers in the standard library was simply a way to standardize the tools they had already been using.

2- Range based loop:

BOOST_FOREACH is a macro provided by the Boost library in C++ to simplify iterating over containers. It predates the range-based for loop introduced in C++11 and offers a way to write cleaner and more readable code.

3- C++ Concepts

Before concepts, enable_if from <type_traits> was used to conditionally enable function templates and class specializations based on traits. It is more verbose and harder to read, often leading to complex syntax.

4- Lambda Expressions:

The Boost Lambda library allows the creation of small unnamed function objects (lambdas) in C++ that can be used inline where a function object or functor is required. This is particularly useful for short operations and makes code more concise and readable.

This code prints each element of the vector multiplied by 2.

5- constexpr

Before constexpr was introduced in C++11, developers often relied on Boost to achieve similar compile-time constant evaluation. The Boost library offers several utilities and techniques that can help mimic the behavior of constexpr.

Although not a direct replacement, BOOST_STATIC_ASSERT can be used to enforce compile-time assertions, ensuring that certain conditions are met during compilation.

Example:

Boost.MPL provides also tools for compile-time computations, which can be used to achieve behavior similar to constexpr for template metaprogramming.

Example:

And finally Boost.Hana is a modern metaprogramming library that provides more powerful and flexible compile-time capabilities, similar to constexpr.

Example:

6- Type Traits

C++11: std::is_same, std::enable_if, etc.
Boost: boost::is_same, boost::enable_if, etc.

  • Boost provided type traits and SFINAE utilities for template metaprogramming.

Example:

7- Static Assertions

C++11: static_assert
Boost: BOOST_STATIC_ASSERT

  • Boost allowed compile-time assertions to catch errors early.

Example:

8- Regular Expressions

C++11: std::regex
Boost: boost::regex

  • Boost provided a powerful regular expression library.

Example:

9- Tuples

C++11: std::tuple
Boost: boost::tuple

  • Boost provided a way to return multiple values from a function.

Example:

10- Chrono

C++11: std::chrono
Boost: boost::chrono

  • Boost provided utilities for time duration and clocks.

Example:

11- Threading

C++11: std::thread
Boost: boost::thread

  • Boost provided threading capabilities before it was standardized.

Example:

Certainly! Here are some additional examples of how Boost provided functionality before they were standardized in C++11 and later versions:

12- Function Objects

C++11: std::function
Boost: boost::function

  • Boost offered boost::function to store callable objects.

Example:

13- Bind

C++11: std::bind
Boost: boost::bind

  • Boost allowed binding function arguments to create partial function applications.

Example:

14- Optional

C++17: std::optional
Boost: boost::optional

  • Boost provided boost::optional for optional values, useful for functions that might not return a value.

Example:

15- Any

C++17: std::any
Boost: boost::any

  • Boost provided a type-safe container for single values of any type.

Example:

16- Variant

C++17: std::variant
Boost: boost::variant

  • Boost provided a type-safe union that can hold one of several types.

Example:

17- Filesystem

C++17: std::filesystem
Boost: boost::filesystem

  • Boost offered functionality for filesystem operations.

Example:

Conclusion

Boost has historically filled many gaps in the C++ standard library, providing advanced features and utilities that were later adopted by the C++ standard. These examples show how Boost helped C++ developers write more expressive and efficient code before the features were officially standardized in C++11 and later versions.