I want to understand the Standard Template Library (STL) in excruciating detail and the best way is to implement it. I'm starting off with std::vector as it is relatively simple algorithmically but a fundamental container.

This is not intended for production use. It is targeting C++-23 . There's no attempt to be portable or backward compatible beyond following good practices. There's no obfuscating names with __ to avoid conflicts with other code.

Ideally, no std code is used (see exceptions below).

The namespace is pw and include files are pw/<name>. Most of the actual implementations are in pw/impl/<file.h>. In fact, most of the STL include files consist primarily of including various implementation files.

The namespace pw::internal is for private details and are in pw/internal/<file.h>. These should not be used by other code.

Unit tests are in tests/unit/<file.t.cpp> and use the catch2 framework.

• <limits> and <stdexcept> are used from std because it seems like a lot of work for not much gain.
• std::initializer_list is inherently a compiler builtin struct
• is_class used builtin __is_class(Type). Because I couldn't implement a working version.
• is_union used builtin __is_union(Type). ditto.
• is_nothrow_constructible used builtin __is_nothrow_constructible(Type, Args...). ditto

Need the following unit tests to be written:

• vector::vector((vector&& other, const Allocator& alloc)
• vector::shrink_to_fit()
• vector::reserve()
• vector::::operator=(vector&& other) noexcept when different