TypeScript offers special syntax for turning a constructor parameter into a class property with the same name and value. These are called parameter properties

Because std::unique_ptr is designed with move semantics in mind, copy initialization and copy assignment are disabled. If you want to transfer the contents managed by std::unique_ptr, you must use move semantics.

the goal of the move constructor and move assignment is to move ownership of the resources from one object to another (which is typically much less expensive than making a copy).

By default, C++ will provide a copy constructor and copy assignment operator if one is not explicitly provided. These compiler-provided functions do shallow copies, which may cause problems for classes that allocate dynamic memory. So classes that deal with dynamic memory should override these functions to do deep copies.

One of the best things about classes is that they contain destructors that automatically get executed when an object of the class goes out of scope. So if you allocate (or acquire) memory in your constructor, you can deallocate it in your destructor, and be guaranteed that the memory will be deallocated when the class object is destroyed (regardless of whether it goes out of scope, gets explicitly deleted, etc…).

Same feature in TypeScript¶ It's worth mentioning that other languages have a shortcut for assignment var assignment directly from constructor parameters. So it seems especially painful that Ruby, despite being so beautifully elegant and succinct in other areas, still has no such shortcut for this. One of those other languages (CoffeeScript) is dead now, but TypeScript remains very much alive and allows you to write this (REPL): class Foo { constructor(public a:number, public b:number, private c:number) { } } instead of this boilerplate: class Foo { constructor(a, b, c) { this.a = a; this.b = b; this.c = c; } } (The public/private access modifiers actually disappear in the transpiled JavaScript code because it's only the TypeScript compiler that enforces those access modifiers, and it does so at compile time rather than at run time.) Further reading: https://www.typescriptlang.org/docs/handbook/2/classes.html#parameter-properties https://basarat.gitbook.io/typescript/future-javascript/classes#define-using-constructor https://kendaleiv.com/typescript-constructor-assignment-public-and-private-keywords/ I actually wouldn't mind being able to use public/private modifiers on instance var parameters in Ruby, too, but if we did, I would suggest making that be an additional optional shortcut (for defining accessor methods for those instance vars) that builds on top of the instance var assignment parameter syntax described here. (See more detailed proposal in #__.) Accessors are more of a secondary concern to me: we can already define accessors pretty succinctly with attr_accessor and friends. The bigger pain point that I'm much more interested in having a succinct shortcut for is instance var assignment in constructors. initialize(@a, @b, @c) syntax¶ jsc (Justin Collins) wrote in #note-12: jjyr (Jinyang Jiang) wrote: I am surprised this syntax has been repeatedly requested and rejected since 7 years ago. ... As someone who has been writing Ruby for over 10 years, this syntax is exactly that I would like. I grow really tired of writing def initialize(a, b, c) @a = a @b = b @c = c end This would be perfect: def initialize(@a, @b, @c) end I'm a little bit sad Matz is against this syntax, as it seems so natural to me. Me too!! I've been writing Ruby for over 15 years, and this syntax seems like the most obvious, simple, natural, clear, unsurprising, and Ruby-like. I believe it would be readily understood by any Rubyist without any explanation required. Even if you saw it for the first time, I can't think of any way you could miss or misinterpret its meaning: since @a is in the same position as a local variable a would normally be, it seems abundantly clear that instead of assigning to a local variable, we're just assigning to the variable @a instead and of course you can reference the @a variable in the constructor body, too, exactly the same as you could with a local variable a passed as an argument. A workaround pattern¶ In the meantime, I've taken to defining my constructor and list of public accessors (if any) like this: attr_reader \ :a, :b def new( a, b) @a, @b = a, b end ... which is still horrendously boilerplatey and ugly, and probably most of you will hate — but by lining up the duplicated symbols into a table of columns, I like that I can at least more easily see the ugly duplication and cross-check that I've spelled them all correctly and handled them all consistently. :shrug: Please??¶ Almost every time I write a new class in Ruby, I wish for this feature and wonder if we'll ever get it. Can we please?

Having a member in a class and initializing it like below:class Foo { x: number; constructor(x:number) { this.x = x; }}is such a common pattern that TypeScript provides a shorthand where you can prefix the member with an access modifier and it is automatically declared on the class and copied from the constructor. So the previous example can be re-written as (notice public x:number):class Foo { constructor(public x:number) { }}

The answer is no, we use a pattern where we do this, and have a `static` method for manufacturing the constructor.e.g.static from({prop1, prop2}) => new this(public prop1, public prop2)

TypeScript includes a concise way to create and assign a class instance property from a constructor parameter.