CPP Any

A Nim wrapper for C++'s std::any.

Example

import cppany

var a: Any = 1
echo castAny[int](a) # 1
a = 2.5
echo castAny[float](a) # 2.5
a = 'A'
echo castAny[char](a) # 'A'

Note

• Do not get confused with the Any type from this module and that from std/typeinfo. (In this manual, Any refers to the former.) Those two types should not be used in the same module, even if it's possible.

• One can only cast Any to the type of which it stores (via castAny), otherwise a BadAnyCast is raised.

• Do not use Any to store GC'ed types (seq, string, ...), unless you fully understand the memory-managing strategy you choose.

• Due to some technical limitations, One cannot have a seq of Any, but can have an array of them.

• As std::any was defined in C++17 (Nim currently uses C++14), this module requires you to pass a flag to the backend C++ compiler (via --passC), telling it to use the new standard. However, if you're with GCC or Clang, it is automatically done by this module, so you don't have to worry about that.

• In a project that uses this module, the {.register.} pragma cannot be used, as it's incompatible with C++17.

References

• https://en.cppreference.com/w/cpp/utility/any

• https://en.cppreference.com/w/cpp/utility/in_place