[C++][CppCon 2018] Concepts is NOW.

Why even though current day job aren't anything about C++ but still coding side projects with it?

Because, it's about logic, math, fundamental computer science and speed. [advanced 'C', close to hardware, abstract with mathematical proofs]

Reference:

https://en.cppreference.com/w/cpp/language/constraints

Type:

• Specifies the set of operations that can be applied to an object  
• implicitly and explicitly
• relies on function declaration and language rules
• Specifies how an object is laid out in memory

Concept:

• Specifies the set of  operations that can be applied to an object.
• implicitly and explicitly
• relies on use patterns
• Reflecting function declarations and language rules
• Says nothing about the layout of the object

The fundamental is function overloading.
The fundamental of the fundamental is: name mangling :-)

Concepts:
Pros:

• Better design
• Readability, maintainability
• Overloading
• Fewer traits (duh~ brain teasing~)

 
Cons:

•     I'll give it a try with examination.

 
Syntax Keywords:
requires (expression)

Concepts act as type for variable declaration:

Input_channel ch = foobar();

e.g

template<InputIterator Iter, typename Value>
    requires EqalityComparable<Value_type<Iter>, Value>
Iter find(Iter first, Iter last, Value val);

Golang doesn't support generic, thus we can see
in 'sort' package it uses 'interface' with member function
as contracts to sort data and Search takes a closure to capture
data structure that needs to be searched with a binary search.
Like python's bisect module, with strong type.